ugjohna@BUFFALO.CSNET (John Arrasjid) (01/04/86)
For those of you who read the article in net.micro.atari about upgrading to 1meg of memory on the ST, DON'T!!!! First of all, the references to the different gauge tinned bus wires and non-tinned bus wires are not clear as are the directions for adding the resisters to pins 6, 7 and 8 of the memory controller. Second of all, when you finally get all the wiring done and turn on the computer, the screen comes on for about 2 seconds and then goes blank without booting the drive. Trying to reboot again does the same thing. I suggest to all of you to wait for some kind of commercial memory upgrade before you fool with your ST. If anyone can tell me what chips I fried from my description, I'd appreciate it. I hope they were just the memory chips. (I tried the two TOS chips, the drive controller, and the graphics chip in another 520ST and they work fine, so that just leaves the MMU, GLUE, and the memory chips. John Arrasjid SUNY/Buffalo Computer Science UUCP: [decvax,dual,rocksanne,watmath,rocksvax]!sunybcs!ugjohna CSnet: ugjohna@buffalo ARPAnet: ugjohna%buffalo@CSNET-RELAY
tynor@gitpyr.UUCP (Steve Tynor) (01/04/86)
In article <8601040742.AA05555@ucbvax.berkeley.edu> ugjohna@BUFFALO.CSNET (John Arrasjid) writes: >For those of you who read the article in net.micro.atari about upgrading to >1meg of memory on the ST, DON'T!!!! I guess I was a lucky one. I've upgraded to 1Meg and everything worked right the first time. I have to disagree about the clarity of Gert's instructions. I found them very easy to follow, providing step-by-step guidance through the procedure. My guess is that you fried a DRAM (they're **very** intolerant of static electricity... Did you ground yourself to a local ground every time you handled them? =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= No problem is so formidable that you can't just walk away from it. Steve Tynor Georgia Instutute of Technology ...{akgua, allegra, amd, harpo, hplabs, ihnp4, masscomp, ut-ngp, rlgvax, sb1, uf-cgrl, unmvax, ut-sally} !gatech!gitpyr!tynor
franco@iuvax.UUCP (01/05/86)
The fact that your screen has raster for two seconds and then goes blank does not mean that you fried anything. My guess is that all chips are fine. Look for solder bridges (your new connections) in the following way: hold the board up to a strong light (light is on the underside of the board and you are looking from topside of board) and USING A 10X MAGNIFYING GLASS (important - use a GOOD magnifying glass) scan all new connections visible from topside for bridges. Then, turn the board over and inspect all new capacitor connections. If you bent the capacitor leads too much one or more may be making contact with some trace. Then, reseat the memory controller chip. Sometimes board flexing will unseat that chip. I suggest you do all this work on a table covered with sheets of aluminum foil and make sure you, the board and anything that contacts the board are at the same electrical potential by keeping everthing in contact with the foil (with the power off, of course) as often as possible. When you power up make sure the aluminum foil is somewhere else. This message is being brought to you by a fully functioning 1MEG 520ST. P.S. If the above fails I will buy the board from you (with everything on it) for, say $50.
info-atari@ucbvax.UUCP (01/06/86)
You probably got your wires on the bottom of u15 in the wrong places. The instructions are a bit wrong in that the chip counts clockwise from the bottom(wirng side). You probably haven't fried anything. You should, however, install the other three 68 ohm resistors in series with the RAS and CAS lines for the original memory chips. I just did 3 units this weekend and all work well. The symptom you describe can be duplicated by moving the wires on u15. Also, if you don't put the filter capacitors back in, the exact same symptom will occur, with NO damage if not left on for too long.
tlz@druxu.UUCP (ZrustTL) (01/06/86)
In reference to article from: ugjohna@BUFFALO.CSNET (John Arrasjid) The instructions for the 1 meg upgrade seemed fine to me and my machine worked just fine after installation. Sure is nice to have a 360K RAMdisk and memory to spare for $42. I'm not sure this task is for everyone, but if you've got the tools and skills, go for it! -- Terry Zrust AT&T-ISL Denver, CO (303) 538-4547
lbl@druhi.UUCP (LocklearLB) (01/06/86)
I have successfully upgraded my 520ST to 1MEG using the original instructions posted to the net. I have the following questions to ask: 1) has anyone successfully upgraded to 1MEG using the new, revised instructions? 2) has anyone who successfully upgraded using the old instructions gone back and successfully retro-fitted the resistors? 3) has anyone with the 1MEG upgrade installed ROMS (not EPROMS) successfully? (either with or without the extra resistors) Thanks in advance for the info. Barry Locklear AT&T Information Systems Labs Denver, CO ihnp4!druhi!lbl (303) 538-7245 >For those of you who read the article in net.micro.atari about upgrading to >1meg of memory on the ST, DON'T!!!! First of all, the references to the >different gauge tinned bus wires and non-tinned bus wires are not clear as >are the directions for adding the resisters to pins 6, 7 and 8 of the memory >controller. Second of all, when you finally get all the wiring done and turn >on the computer, the screen comes on for about 2 seconds and then goes blank >without booting the drive. Trying to reboot again does the same thing. I >suggest to all of you to wait for some kind of commercial memory upgrade >before you fool with your ST. If anyone can tell me what chips I fried from >my description, I'd appreciate it. I hope they were just the memory chips. (I >tried the two TOS chips, the drive controller, and the graphics chip in another >520ST and they work fine, so that just leaves the MMU, GLUE, and the memory >chips. >John Arrasjid SUNY/Buffalo Computer Science
info-atari@ucbvax.UUCP (01/07/86)
I missed the article about the 1 Meg upgrade. Could you please send a copy to me. Maybe I can figure out what is wrong. Thanks terry
info-atari@ucbvax.UUCP (01/07/86)
I missed the 1 Meg upgrade article. Would you send a copy to me. I may be able to correct the problem or have a better understanding of what is involved. Thanks in advance...... Terry McNeill 13941 Olive Mesa Ct. Poway, Ca. 92064 or Via Electronic Mail
info-atari@ucbvax.UUCP (01/08/86)
------------------------ The "original" article ------------------------ >From drutx!ihnp4!mhuxn!mhuxr!ulysses!burl!clyde!bonnie!akgua!whuxlm!harpo!decvax!genrad!panda!talcott!harvard!seismo!lll-crg!gymble!umcp-cs!eneevax!ravi Mon Sep 9 18:14:26 1985 Relay-Version: version B 2.10.1 (Denver Mods 7/26/84) 6/24/83; site druhi.UUCP Posting-Version: version B 2.10.1 6/24/83; site eneevax.UUCP Path: druhi!drutx!ihnp4!mhuxn!mhuxr!ulysses!burl!clyde!bonnie!akgua!whuxlm!harpo!decvax!genrad!panda!talcott!harvard!seismo!lll-crg!gymble!umcp-cs!eneevax!ravi From: ravi@eneevax.UUCP (Ravi Kulkarni) Newsgroups: net.micro.atari Subject: 1 Meg ST upgrade (long) Message-ID: <360@eneevax.UUCP> Date: Mon, 9-Sep-85 18:14:26 MDT Article-I.D.: eneevax.360 Posted: Mon Sep 9 18:14:26 1985 Date-Received: Wed, 11-Sep-85 23:00:50 EDT Distribution: net Organization: U of Maryland, EE Dept., College Park, MD Lines: 213 I am forwarding these instructions to the net as the original author does not have access to usenet. So far he and I as far as I know are the only ones who have upgraded to 1 meg. If you are brave enough to try this upgrade you might want to let us know if you succeeded or perish the thought failed. -ravi ================================================================ Date: Wed, 28 Aug 85 20:53:05 pdt From: Gert Slavenburg <gert@Pescadero> Subject: manual to 520ST 1 Meg upgrade To: info-st@eneevax Status: RO I had enough requests to justify sending this out to all of you at info-st. Good luck with the modification. Cheers will be appreciated, as well as examples of use of the full 1 Meg - it's lonely at the top. Directions for expanding the Atari 520ST memory to 1 MByte ========================================================== WARNING : This is a hardware modification that will void the warranty of your 520ST. If you do not have the appropriate tools or experience you have a substantial chance of ruining your 520ST. Proceed at your own risk ! This modification has been in my 520ST without any problems for 6 days now. However, I have (of course) not checked with knowledgable sources at Atari to verify if this modification endangers the long term machine reliability and/or software compatibility (I suspect it may endanger their software compatibility if enough of us do it !). tools/components needed : ========================= 16 256k * 1 RAM chips, 150 nSec. access time type, e.g. NEC 41256C-15. (available at e.g. Fry's Electronics, Sunnyvale, CA for $ 2.77 each) A good quality, preferrably temperature controlled soldering iron, with a miniature tip (tip should be narrow enough to avoid touching 2 I.C. pins at the same time). E.g. Weller type soldering station. Good quality resin core solder (thin). Approximately 4 foot of wire-wrap wire and a good stripper for it. (you will have to route 3 wire's over a sequence of I.C. pins. The easiest way to do this is to have a stripper allowing you to shift the isolation forward over the wire, solder the next point, measure new length, shift over insulation etc. until the endpoint). The "No Nik" .014" (dark green handle) wire wrap stripper is the best tool for this. Available e.g. at Jensen tools, Phoenix, AZ (602) 968-6231 catalog no H4B305. De-soldering wick and solder suction tool. Philips type screwdriver (for opening your ST), tweezers, pliers etc. A steady hand and self-confidence. explanation of the modification : ================================= (Please read the rest of this document before starting. It may save you time and a 520ST) The current memory inside the 520ST consists of 16 256k*1 RAM chips. Address (A0..A8) lines are common to all those chips. The WriteEnable line is also common to all chips. Data (in and out) lines are (of course) individual. The RAS (Row-Address Strobe) line is common to all chips. The 8 chips forming the high order byte group have one common CAS line, and the 8 forming the low order byte group have one common CAS line (CAS is used as enable for write operations, suchthat WriteEnable can be common to both groups). The high order group from MSB to LSB consists of U45,44,43,42,38,34,33,32. The low order group of U30,29,28,25,24,18,17,16. Note that all chips are adjacent, though the numbering has gaps. RAS0, CAS0H and CAS0L are supplied from U15 pin 8,6 and 7 respectively. (The 0 indicates bank 0) Bank 1 that you are going to build in will be "piggy-backed" on top of the current chips, where all pins of the new chips EXCEPT RAS (pin 4) and CAS (pin 15) are soldered to the old chips equivalent pin. Thus they will end up sharing addresses, data, WriteEnable and power and ground with the existing chips. All RAS pins of the new chips are wired together and will be supplied with the "RAS1" signal generated on pin 18 of U15 (the Memory Controller, marked 3H-2119CC or so). The CAS pins of the 8 new high order byte chips (on top of U45..U32) are wired together and supplied from the "CAS1H" signal generated on pin 22 of U15. Analogously, the CAS pins of the new U30 to U16 are wired together and supplied with "CAS1L" from pin 21 of U15. how to go about it : ==================== step 1 : Open up your 520ST, pull of the keyboard connector, and remove the main circuit card from its top and bottom shielding. Make sure to remember which screws go where and note the keyboard connector orientation. step 2 : Desolder all the capacitors adjacent to the existing RAM chips. (DO NOT SKIP THIS STEP. You'll loose time if you do, and worse, the modification will not be reliable since you can't solder the pins obstructed by the capacitors reliably (if at all)). To desolder them, I found it easiest to heat the island on the non component side, and bend the wires straight. After doing that for each capacitor, turn over to the component side and heat the islands while pulling the capacitor out with tweezers. step 3 : Open up the holes of all the desoldered capacitors, using a combination of de-soldering wick and suction tool. Do this from the non-component side. If certain holes are difficult to open up, you may want to use a wood splinter. (push it through while heating). Be carefull to remove all solder debris ! THE REASON for opening the holes NOW is that they will be less accessible once you've done the other steps ! Patience is a virtue. (NOTE : Step 2 and 3 are the only ones that may damage your ST PCboard. Be sure not to use excessive force while pulling out the capacitors. If you damage your PCboard anyway, cure the problem now and not later). step 4 : In this step we will piggyback the new RAM's on top of the old ones. Be sure to connect all pins except pin 4 (RAS) and 15 (CAS). The best way to go about this is to do chip by chip. First bend the pins of the new RAM's suchthat they are perpendicular to the package (instead of having slightly spread "cowboy legs"). Use pliers to bend pin 4 and 15 suchthat it comes out of the I.C. package horizontal, and cut of the excess length of pins 4 and 15 (I mean part of the pin, you still need to be able to solder to it!). Make sure that the new RAM fits snugly on top of the old one (in the same orientation !!!!), without intervening space and with the new pins touching the old ones. Now solder each pin (except the non-touching 4 and 15) to the other RAM's. The best way to do this with least chance of damage is to touch both the new RAM's pin and the old RAM's pin. Heat them both for a second and add A LITTLE solder then. Wait till the solder flows. After each IC, check all pins carefully to assure a good connection. (use a magnifying glass) NOTE : This step is crucial for the long term reliability of the memory extension. A badly soldered joint may show up later as sporadic memory errors. TAKE YOUR TIME. (NOTE : until step 6 is finished, do not in any way apply power to your ST. This intermediate state of affairs will damage your memory chips !) step 5 : Re- mount all the desoldered capacitors. Bend the pins like they were before re-soldering, suchthat they will not touch the lower shielding. Solder from the non-component side. step 6 : In this step you will route the 3 wires mentioned earlier. The first wire connects pin 4 (RAS) of all new RAM's to pin 18 of U15. The second wire connects pin 15(CAS) of the new U45 to U32 to pin 22 (CAS1H) of U15. The third wire connects pin 15 (CAS) of the new U30 to U16 to pin 21 of U15. The best way to do this is to use the stripper to remove 5 inches of isolation. Solder the first IC pin to the end of the blank wire, measure the distance to the next pin in sequence and shift over that amount of isolation. Continue in this fashion untill all pins in the sequence are done. Work from U45 to the left, soldering directly to the leftover pins on the new chips. Make sure that no wire or solder sticks out above the top plane of the new chips, since they will almost touch the top shielding ! Route the wires through the PC board hole below and to the left of U15 to connect to U15 on the non-component side. step 7 : Sit back. Use brain. Do you feel confident about the quality of your work ? No mistakes ? Check everything once again if you are but a little uncertain. Applying power with errors might make your ST into a decorative, non-functional piece of art. OK. Either rebuild your ST into its shielding and cabinet, or put it onto a surface clear of wires and solder-remains and connect it to monitor, disk and supply. Boot it. If it boots, you're probably there. Test if the new memory works by looking at the phystop variable ($42E) with SID if you have the developper stuff. It should read $100000 (1M hex). Also note that memcntlr ($424) now holds 5 instead of 4, and that v_bas_ad ($44E) now holds $F80000 (screen bitmap origin). If you don't have the developper stuff, try a single drive copy and check that you get the whole disk in one buffer instead of two. If the new memory does not seem to exist, use SID to deposit and retrieve words on locations $80000 and up (1/2 M hex). If bit errors occur, the ST bootROM did not detect the extension (it checks all bits of 512 locations by testing a pseudo random sequence, before accepting a memory bank). Try to pinpoint the faulty chip(s) and remove the error. If it doesn't boot, you're in trouble. I'm sorry. It is difficult to give hints on what to do here. So many possibilities. Desoldering the new chips probably won't work (if the old ones were functional, the ST would still boot). Check for hidden short-circuit on RAM pins. May also be that you have a flaky new pin connection. Good luck. I feel bad. Well, I might be able to help you a little, call me when you're really stuck ! Evenings at (415) 965-7696. Not after september - I'll be out of USA by then. PLEASE : ======== Let me know if you did the modification and failed or succeeded. I'd like to know how many people benefit from this and if it's safe enough for large scale application. Mail to arpanet address gert@su-pescadero. ==================================================================== -- ARPA: eneevax!ravi@maryland UUCP: [seismo,allegra]!umcp-cs!eneevax!ravi --------------------------- The "second" article -------------------- > ~~~~~~~~~~~~~~~~~~~pop goes the ST~~~~~~~~~~~~~~~~~~~ > > i just fried my ST and after talking to atari and my local dealer i > have tracked down the problem. It is related to the 1 Meg upgrade > and the new proms, it seems that the early postings of "how to > upgrade ...." left out 4 critical resisters (60 ohm 10% tol); 2 must > be placed on the CAS lines and 2 on the RAS lines, all 4 go on the > MMU (i know it isnt really an MMU) side. the upgrade will work fine > w/o the resistors until you put in the new proms, the difference in > the current drain will cost you all your memory chips and possibly > the MMU. > -- > god bless Lily St. Cyr > -Rocky Horror Picture Show > > Name: James Turner > Mail: Imagen Corp. 2650 San Tomas Expressway, P.O. Box 58101 > Santa Clara, CA 95052-9400 > AT&T: (408) 986-9400 > UUCP: ...{decvax,ucbvax}!decwrl!imagen!turner After reading the above article, I downloaded the revised procedure from Compu Serve. I have had the upgrade for about 3 months, and has worked without a flaw. I would have probably added the proms without the resistors. Thanks to Mr. Turner for the warning. Here is a copy of the revised procedure: NOTE: This is an REVISED,TESTED version of the original text downloaded from CompuServe. December 6, 1985 (This was REVISED AND TESTED by an annonymous engineer on Atari's developement staff. The addition of the resistors should provide a long life to your machine, but the warning below is STILL IN EFFECT. This is not an official sanction of the modification. USE WITH CARE!!!) Here's the 1 Meg upgrade directions: I have brought this over un-editted from the arpanet info-st mailing list. I TAKE NO RESPONSIBILITY FOR ITS CONTENT OR ACCURACY. I HAVE NOT TRIED THIS MODIFICATION ON MY OWN ST AS YET. I AM PASSING THIS ALONG TO THOSE WHO DO WISH TO TRY IT. FOLLOW THE DIRECTIONS AT YOUR OWN RISK. --Dwight McKay (75776,1521) From: gert@pescadero WARNING: This is a hardware modification that will void the warranty of your 520ST. If you do not have the appropriate tools or experience you have a substantial chance of ruining your 520ST. Proceed at your own risk! This modification has been in my 520ST without any problems for 6 days now. However, I have (of course) not checked with knowledgable sources at Atari to verify if this modification endangers the long term machine reliability and/or software compatibility (I suspect it may endanger their software compatibility if enough of us do it!) Tools & components needed : 16 256k * 1 RAM chips, 150 ns access time type, e. g. NEC 41256C-15 (avilable at e. g. Fry's Electronics, Sunnyvale, CA for $2.77 each) A good quality, preferrably temperature controlled soldering iron, with a minature tip (tip should be narrow enough to avoid touching 2 I. C. pins at the same time). E. g. Weller type soldering station. Good quality resin core solder (thin). Approximately 4 foot of #24 AWG insulated wire and a good stripper for it and 2 feet of #22 AWG solid tinned copper bus wire. You will have to route 3 wires over a sequence if I.C. pins. Desoldering wick and solder suction tool. Philips type screwdriver (for opening your ST), tweezers, pliers, etc. A steady hand and self-confidence. Explaination of the modification : (Please read the rest of this document before starting. It may save you time and an 520ST) The current memory inside the 530ST consists of 16 256K*1 RAM chips. Address (A0..A8) lines are common to all those chips. The WriteEnable line is also common to all chips. Data (in and out) lines are of course individual. The RAS (row-address strobe) line is common to all chips. The 8 chis foring the high order byte group have one common CAS line, and the 8 forming the low order byte group have one common CAS line (CAS is used as enable for write operations, such that WriteEnable can be common to both groups). The high order group from MSB to LSB consists of U45, 44, 43, 42, 38, 34, 33, 32. The low order group of U30, 29, 28, 25, 24, 28, 27, 26. Note that all chips are adjacent, though the numbering has gaps. RAS0, CAS0H, and CAS0L are supplied from U1 pin 8,6 and 7 respectively (The 0 indicates bank 0) Bank 1 that you are going to build in will be "piggy-backed" on top of the current chips, where all pins of the new chips EXCEPT RAS (pin 4) and CAS (pin 15) are soldered to the old chips equivalent pins. Thus they will end up sharing addresses, data, WriteEnable and power and ground with the existing chips. All RAS pis of the new chips are wired together and will be supplied with the "RAS1" signal generated on pin 18 of U15 (the memory controller, marked 3H-2119C or so). The CAS pins of the 8 new high order byte chips (on top of U45..U32) are wired together and supplied from the "CAS1H" signal generated on pin 22 of U15. Analogously, the CAS pins of the new U30 to U16 are wired together and supplied with "CAS1L" from pin 21 of U15. How to go about it: Step 1: Open up your 520ST, pull off the keyboard connector and remove the main circuit card from its top and bottom shielding. Make sure to remember which screws go where and note the keyboard connector orientation. Step 2: Desolder all of the capacitors adjacent to the existing RAM chips. (DO NOT SKIP THIS STEP. You'll lose time if you do, and worse, the modification will no be reliable since you can't solder pins obstructed by the capacitors reliably (if at all)). To desolder them, I found it easiest to heat the island on the non component side, and bend the wires straight. After doing that or each capacitor, turn over to the component side and heat the islands wile pulling the capacitor out with the tweezers. Step 3: Open up the holes of all the desoldered capacitors, using a combiation of de-soldering wick and suction tool. Do this from the non component side. If certain holes are difficult to open up, you may want to use a wood splinter. (push it through while heating). Be carefull to remove all solder debris!! THE REASON for opening the holes NOW is that they will be less accessible once you've done the other steps! Patience is a virtue. (NOTE: Step 2 & 3 are the only ones that may damage your ST PC board. Be sure not to use excessive force while pullling out the capacitors. If you damage your PC board anyway, cure the problem now and not later). Step 4: In this step we will piggyback the new RAM's on top of the old oes. Be sure to connect all pins except pin 4 (RAS) and 15 (CAS). The best way to go about this is to do chip by chip. First, bend the pins of the new RAM's suchthat hey are perpendicular to the package (instead of having slightly spread "cowboy legs"). Use pliers to bend pin 4 and 15 such that the legs are 180 degrees from their normal position, so they stick up in the air above the plane of the top surface of the chips. Don't make an absolute sharp 180 degree bend since some manufacturers' pins may snap off. Leave a little curve in the leg, but insure that is above the plane of the top surface of the chip. Using #22 AWG to #16 AWG tinned solid copper wire you will form three buses along the top surface of the new d-rams. Cut a #22 AWG solid copper wire the length of the 16 d-rams on the PCB. The RAS bus is formed by soldering all the pin 4's of the new d-rams to the solid copper wire. The bus wire must be seated against the top surface of the new d-rams without a gap. This insures clearance between the top shield and the pins of the d-rams. After soldering all 16 d-rams to the bus clip off any portion of the pins that extend above the top of the bus wire. Now cut a #22 AWG solid copper wire the length of the 16 d-rams. Place the bus wire along the top surface of the new d-rams in contact with all the pin 15's of the new d-rams. Solder every pin 15 to this bus and as above insure that the wire is seated solidly against the top surface of the new d-rams. Cut off all excess pin length sticking up above the top of the bus wire. Using diagonal cutters remove the section of the bus connecting the new U30 pin 15 to the new U32 pin 15. This divides the bus in half with the new U16, 17, 18, 24, 28, 29 having a common pin 15. The new U32, 33, 34, 38, 42, 43, 44, 45 now have a common pin 15, seperated from the other common bus. (NOTE: until step 6 is finished, do no in any way apply power to your ST. This intermediate state of affairs will damage your memory chips!!) Step 5: Remount all the desoldered capacitors. Bend the pins like they were before resoldering, suchthat they will not touch the lower shielding. Solder from the non component side. Step 6: Orient the 520ST PCB so that you are looking at the solder side of the PCB (non-component side), with the row of d-rams nearest you. Find the double square pattern of pads at the 68-pin socket of the memory controller, U15 (3H2119). The following is a guide to locating the six memory controller pins necessary to complete the wiring. The socket is numbered conterclockwise, starting with pin 1, the square pad (look closely) in the middle of the bottom outside row. The sequence, moving counterclockwise from pin 1, first on the outside square ONLY: (NOTE: the sequence ")(" means to make a 90-degree turn counterclockwise, i.e. around the corner) 1,3,5,7,9)(10,12,14,16,18,20,22,24,26)(27,29,31,33,35,37,39, 41,43)(44,46,48,50,52,54,56,58,60)(61,63,65,67 The sequence, moving counterclockwise along the inside square only, and starting with the left side of the bottom row: (62,64,66,68,2,4,6,8)(11,13,15,17,19,21,23,25)(28,30,32,34,3 6,38,40,42)(45,47,49,51,53,55,57,59) Six 68-ohm 1/4W plus/minus 10% carbon film resistors must be added when adding memory. These series terminating resistors minimize undershoot which may damage BOTH BANKS of d-rams if omitted. Solder a 68-ohm resistor to pin 18 of U15, RAS1. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to the pin 4 bus (RAS) of all the new d-rams. that is the new U16, 17, 18, 24, 25, 28, 29, 30, 32, 33, 34, 38, 42, 43, 44, and 45. Solder a 68-ohm resistor to pin 22 of U15, CASH1. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to pin 15 bus (CAS) of the new U45,44,43,42,38,34,33,32. Solder a 68-ohm resistor to pin 21 of U15, CASIL. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to pin 15 bus (CAS) of the new U30, 29,28,25,24,18,17,16. For best results in all three cases above solder the wires coming from the resistors to the middle of the three bus wires in a "T" fashion rather than at one end of the buses. Use a continuity tester to find the following three traces -- do not depend on visual inspection. Now install three 68-ohm series terminating resistors in the original 512K bank of ram. Be very careful while soldering to these narrow traces, since excessive heat can easily lift a trace from the board. Use an Exacto knife to gently remove solder mask from traces. Cut the trace leading from pin 8, RAS0, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Cut the trace leading from pin 6, CAS0H, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Cut the trace leading from pin 7, CAS0L, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Step 7: Sit back. Use Brain. Do you feel confident about the quality of your work? No mistakes? Check evrything once again if you are but a little uncertain. Applying power with errors might make your ST into a decorative, nonfunctional piece of art. OK. Either rebuild your ST into its shielding and cabinet, or put it onto a surface clear of wires and solder remians and connect it to monitor, disk and supply. Boot it. It it boots, you're probably there. Test if the new memory works by looking at the phystop variable ($42E) with SID if you have the developer stuff. It should read $100000 (1M hex). Also note that memcntlr ($424) now holds 5 instead of 4, and that v_bas_ad ($44E) now holds $F80000 (screen bitmap origin). If you don't have the developer stuff, try a single drive copy and check that you get the whole disk in one buffer instead of two. If the new memory does not seem to exist, use SID to deposit and retrieve words on locations $80000 and up (1/2 Meg hex). If bit errors occur, the ST bootROM did not detect the extension (it checks all bits of 512 locations by testing a psedo random sequence, before accepting a memory bank). Try to pin point the faulty chip(s) and remove the error. If it doesn't boot, you're in trouble. I'm sorry. It is difficult to give hints on what to do here. So many possibilities. Desoldering the new chips probably won't work (if the old ones were functional, the ST would still boot). Check for hidden short:circuit on the RAM pins. May also be that you have a flaky new pin connection. That's all there is... -- Jwahar R. Bammi Usenet: .....!decvax!cwruecmp!bammi CSnet: bammi@case Arpa: bammi%case@csnet-relay CompuServe: 71515,155 ------------------------- That's all folks! ------------------------
info-atari@ucbvax.UUCP (01/09/86)
Here is a copy of the article you requested: > ~~~~~~~~~~~~~~~~~~~pop goes the ST~~~~~~~~~~~~~~~~~~~ > > i just fried my ST and after talking to atari and my local dealer i > have tracked down the problem. It is related to the 1 Meg upgrade > and the new proms, it seems that the early postings of "how to > upgrade ...." left out 4 critical resisters (60 ohm 10% tol); 2 must > be placed on the CAS lines and 2 on the RAS lines, all 4 go on the > MMU (i know it isnt really an MMU) side. the upgrade will work fine > w/o the resistors until you put in the new proms, the difference in > the current drain will cost you all your memory chips and possibly > the MMU. > -- > god bless Lily St. Cyr > -Rocky Horror Picture Show > > Name: James Turner > Mail: Imagen Corp. 2650 San Tomas Expressway, P.O. Box 58101 > Santa Clara, CA 95052-9400 > AT&T: (408) 986-9400 > UUCP: ...{decvax,ucbvax}!decwrl!imagen!turner After reading the above article, I downloaded the revised procedure from Compu Serve. I have had the upgrade for about 3 months, and has worked without a flaw. I would have probably added the proms without the resistors. Thanks to Mr. Turner for the warning. Here is a copy of the revised procedure: NOTE: This is an REVISED,TESTED version of the original text downloaded from CompuServe. December 6, 1985 (This was REVISED AND TESTED by an annonymous engineer on Atari's developement staff. The addition of the resistors should provide a long life to your machine, but the warning below is STILL IN EFFECT. This is not an official sanction of the modification. USE WITH CARE!!!) Here's the 1 Meg upgrade directions: I have brought this over un-editted from the arpanet info-st mailing list. I TAKE NO RESPONSIBILITY FOR ITS CONTENT OR ACCURACY. I HAVE NOT TRIED THIS MODIFICATION ON MY OWN ST AS YET. I AM PASSING THIS ALONG TO THOSE WHO DO WISH TO TRY IT. FOLLOW THE DIRECTIONS AT YOUR OWN RISK. --Dwight McKay (75776,1521) From: gert@pescadero WARNING: This is a hardware modification that will void the warranty of your 520ST. If you do not have the appropriate tools or experience you have a substantial chance of ruining your 520ST. Proceed at your own risk! This modification has been in my 520ST without any problems for 6 days now. However, I have (of course) not checked with knowledgable sources at Atari to verify if this modification endangers the long term machine reliability and/or software compatibility (I suspect it may endanger their software compatibility if enough of us do it!) Tools & components needed : 16 256k * 1 RAM chips, 150 ns access time type, e. g. NEC 41256C-15 (avilable at e. g. Fry's Electronics, Sunnyvale, CA for $2.77 each) A good quality, preferrably temperature controlled soldering iron, with a minature tip (tip should be narrow enough to avoid touching 2 I. C. pins at the same time). E. g. Weller type soldering station. Good quality resin core solder (thin). Approximately 4 foot of #24 AWG insulated wire and a good stripper for it and 2 feet of #22 AWG solid tinned copper bus wire. You will have to route 3 wires over a sequence if I.C. pins. Desoldering wick and solder suction tool. Philips type screwdriver (for opening your ST), tweezers, pliers, etc. A steady hand and self-confidence. Explaination of the modification : (Please read the rest of this document before starting. It may save you time and an 520ST) The current memory inside the 530ST consists of 16 256K*1 RAM chips. Address (A0..A8) lines are common to all those chips. The WriteEnable line is also common to all chips. Data (in and out) lines are of course individual. The RAS (row-address strobe) line is common to all chips. The 8 chis foring the high order byte group have one common CAS line, and the 8 forming the low order byte group have one common CAS line (CAS is used as enable for write operations, such that WriteEnable can be common to both groups). The high order group from MSB to LSB consists of U45, 44, 43, 42, 38, 34, 33, 32. The low order group of U30, 29, 28, 25, 24, 28, 27, 26. Note that all chips are adjacent, though the numbering has gaps. RAS0, CAS0H, and CAS0L are supplied from U1 pin 8,6 and 7 respectively (The 0 indicates bank 0) Bank 1 that you are going to build in will be "piggy-backed" on top of the current chips, where all pins of the new chips EXCEPT RAS (pin 4) and CAS (pin 15) are soldered to the old chips equivalent pins. Thus they will end up sharing addresses, data, WriteEnable and power and ground with the existing chips. All RAS pis of the new chips are wired together and will be supplied with the "RAS1" signal generated on pin 18 of U15 (the memory controller, marked 3H-2119C or so). The CAS pins of the 8 new high order byte chips (on top of U45..U32) are wired together and supplied from the "CAS1H" signal generated on pin 22 of U15. Analogously, the CAS pins of the new U30 to U16 are wired together and supplied with "CAS1L" from pin 21 of U15. How to go about it: Step 1: Open up your 520ST, pull off the keyboard connector and remove the main circuit card from its top and bottom shielding. Make sure to remember which screws go where and note the keyboard connector orientation. Step 2: Desolder all of the capacitors adjacent to the existing RAM chips. (DO NOT SKIP THIS STEP. You'll lose time if you do, and worse, the modification will no be reliable since you can't solder pins obstructed by the capacitors reliably (if at all)). To desolder them, I found it easiest to heat the island on the non component side, and bend the wires straight. After doing that or each capacitor, turn over to the component side and heat the islands wile pulling the capacitor out with the tweezers. Step 3: Open up the holes of all the desoldered capacitors, using a combiation of de-soldering wick and suction tool. Do this from the non component side. If certain holes are difficult to open up, you may want to use a wood splinter. (push it through while heating). Be carefull to remove all solder debris!! THE REASON for opening the holes NOW is that they will be less accessible once you've done the other steps! Patience is a virtue. (NOTE: Step 2 & 3 are the only ones that may damage your ST PC board. Be sure not to use excessive force while pullling out the capacitors. If you damage your PC board anyway, cure the problem now and not later). Step 4: In this step we will piggyback the new RAM's on top of the old oes. Be sure to connect all pins except pin 4 (RAS) and 15 (CAS). The best way to go about this is to do chip by chip. First, bend the pins of the new RAM's suchthat hey are perpendicular to the package (instead of having slightly spread "cowboy legs"). Use pliers to bend pin 4 and 15 such that the legs are 180 degrees from their normal position, so they stick up in the air above the plane of the top surface of the chips. Don't make an absolute sharp 180 degree bend since some manufacturers' pins may snap off. Leave a little curve in the leg, but insure that is above the plane of the top surface of the chip. Using #22 AWG to #16 AWG tinned solid copper wire you will form three buses along the top surface of the new d-rams. Cut a #22 AWG solid copper wire the length of the 16 d-rams on the PCB. The RAS bus is formed by soldering all the pin 4's of the new d-rams to the solid copper wire. The bus wire must be seated against the top surface of the new d-rams without a gap. This insures clearance between the top shield and the pins of the d-rams. After soldering all 16 d-rams to the bus clip off any portion of the pins that extend above the top of the bus wire. Now cut a #22 AWG solid copper wire the length of the 16 d-rams. Place the bus wire along the top surface of the new d-rams in contact with all the pin 15's of the new d-rams. Solder every pin 15 to this bus and as above insure that the wire is seated solidly against the top surface of the new d-rams. Cut off all excess pin length sticking up above the top of the bus wire. Using diagonal cutters remove the section of the bus connecting the new U30 pin 15 to the new U32 pin 15. This divides the bus in half with the new U16, 17, 18, 24, 28, 29 having a common pin 15. The new U32, 33, 34, 38, 42, 43, 44, 45 now have a common pin 15, seperated from the other common bus. (NOTE: until step 6 is finished, do no in any way apply power to your ST. This intermediate state of affairs will damage your memory chips!!) Step 5: Remount all the desoldered capacitors. Bend the pins like they were before resoldering, suchthat they will not touch the lower shielding. Solder from the non component side. Step 6: Orient the 520ST PCB so that you are looking at the solder side of the PCB (non-component side), with the row of d-rams nearest you. Find the double square pattern of pads at the 68-pin socket of the memory controller, U15 (3H2119). The following is a guide to locating the six memory controller pins necessary to complete the wiring. The socket is numbered conterclockwise, starting with pin 1, the square pad (look closely) in the middle of the bottom outside row. The sequence, moving counterclockwise from pin 1, first on the outside square ONLY: (NOTE: the sequence ")(" means to make a 90-degree turn counterclockwise, i.e. around the corner) 1,3,5,7,9)(10,12,14,16,18,20,22,24,26)(27,29,31,33,35,37,39, 41,43)(44,46,48,50,52,54,56,58,60)(61,63,65,67 The sequence, moving counterclockwise along the inside square only, and starting with the left side of the bottom row: (62,64,66,68,2,4,6,8)(11,13,15,17,19,21,23,25)(28,30,32,34,3 6,38,40,42)(45,47,49,51,53,55,57,59) Six 68-ohm 1/4W plus/minus 10% carbon film resistors must be added when adding memory. These series terminating resistors minimize undershoot which may damage BOTH BANKS of d-rams if omitted. Solder a 68-ohm resistor to pin 18 of U15, RAS1. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to the pin 4 bus (RAS) of all the new d-rams. that is the new U16, 17, 18, 24, 25, 28, 29, 30, 32, 33, 34, 38, 42, 43, 44, and 45. Solder a 68-ohm resistor to pin 22 of U15, CASH1. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to pin 15 bus (CAS) of the new U45,44,43,42,38,34,33,32. Solder a 68-ohm resistor to pin 21 of U15, CASIL. Solder a #24 AWG stranded wire from the remaining end of the 68-ohm resistor to pin 15 bus (CAS) of the new U30, 29,28,25,24,18,17,16. For best results in all three cases above solder the wires coming from the resistors to the middle of the three bus wires in a "T" fashion rather than at one end of the buses. Use a continuity tester to find the following three traces -- do not depend on visual inspection. Now install three 68-ohm series terminating resistors in the original 512K bank of ram. Be very careful while soldering to these narrow traces, since excessive heat can easily lift a trace from the board. Use an Exacto knife to gently remove solder mask from traces. Cut the trace leading from pin 8, RAS0, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Cut the trace leading from pin 6, CAS0H, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Cut the trace leading from pin 7, CAS0L, of U15 near U15. Solder a 68-ohm resistor in series with the trace. Step 7: Sit back. Use Brain. Do you feel confident about the quality of your work? No mistakes? Check evrything once again if you are but a little uncertain. Applying power with errors might make your ST into a decorative, nonfunctional piece of art. OK. Either rebuild your ST into its shielding and cabinet, or put it onto a surface clear of wires and solder remians and connect it to monitor, disk and supply. Boot it. It it boots, you're probably there. Test if the new memory works by looking at the phystop variable ($42E) with SID if you have the developer stuff. It should read $100000 (1M hex). Also note that memcntlr ($424) now holds 5 instead of 4, and that v_bas_ad ($44E) now holds $F80000 (screen bitmap origin). If you don't have the developer stuff, try a single drive copy and check that you get the whole disk in one buffer instead of two. If the new memory does not seem to exist, use SID to deposit and retrieve words on locations $80000 and up (1/2 Meg hex). If bit errors occur, the ST bootROM did not detect the extension (it checks all bits of 512 locations by testing a psedo random sequence, before accepting a memory bank). Try to pin point the faulty chip(s) and remove the error. If it doesn't boot, you're in trouble. I'm sorry. It is difficult to give hints on what to do here. So many possibilities. Desoldering the new chips probably won't work (if the old ones were functional, the ST would still boot). Check for hidden short:circuit on the RAM pins. May also be that you have a flaky new pin connection. That's all there is... -- Richard E. Sansom {decvax,ucbvax,ihnp4}!trwrb!trwrba!sansom
turner@imagen.UUCP (D'arc Angel) (01/10/86)
> P.S. If the above fails I will buy the board from you (with everything > on it) for, say $50. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~\ lineater, \~~~~~~~~~~~~~~~~~~~~~~~~~~~~ you're TOO kind (-:) and i aint saying which two, $50 for a couple hundred worth of salvagable chips! com'on -- god bless Lily St. Cyr -Rocky Horror Picture Show Name: James Turner Mail: Imagen Corp. 2650 San Tomas Expressway, P.O. Box 58101 Santa Clara, CA 95052-9400 AT&T: (408) 986-9400 UUCP: ...{decvax,ucbvax}!decwrl!imagen!turner CompuServe: 76327,1575
ugjohna@BUFFALO.CSNET (John Arrasjid) (01/14/86)
Thanks. We finally got it working! John Arrasjid SUNY/Buffalo Computer Science UUCP: [decvax,dual,rocksanne,watmath,rocksvax]!sunybcs!ugjohna
franco@INDIANA.CSNET (John Franco) (01/18/86)
Good. What was wrong?