mitch@manta.NOSC.MIL (Ray Mitchell) (02/04/89)
Has anyone encountered any problems with repeated failures with the 6526A IC IC in the C64? I think they call the IC an ACI. The system has two of them but the one interfacing to the joystick ports and keyboard is the one giving me the problems. I have been through about four of them in the last 2 years and I am ending up investing more in them than I have in the computer. I even bought a different computer thinking it might be something in the system but the new one also blows one about every 6 months (The new C64 is using a different power supply than the old one). The problem usually manifests itself by the joysticks failing to respond to a certain direction or a key on the keyboard failing to operate properly. These ICs cost $17 each from Commodore and about twice that locally. Commodore has no one that I have been able to contact intelligent enough to discuss this problem but I'm sure they would deny a problem anyway. My only solution is to build a replacement from discrete TTL which technically is no problem but I don't beleive the part is explained sufficiently in the programmer's manual to premit this. Commodore is obviously no help on this either. I am using the the C64 strictly for games and it is connected only to a Commodore 1571 drive (no modems, printers, etc.). I get the feeling Commodore has probably just found a good way to make some extra money. Any suggestions will be appreciated. Ray Mitchell
jgreco@csd4.milw.wisc.edu (Joe Greco) (02/04/89)
In comp.sys.cbm article <435@manta.NOSC.MIL>, mitch@manta.NOSC.MIL (Ray Mitchell) wrote: ]Has anyone encountered any problems with repeated failures with the 6526A IC ]IC in the C64? I think they call the IC an ACI. The system has two of them ]but the one interfacing to the joystick ports and keyboard is the one giving ]me the problems. ] ]I have been through about four of them in the last 2 years and I am ending ]up investing more in them than I have in the computer. I even bought a ]different computer thinking it might be something in the system but the ]new one also blows one about every 6 months (The new C64 is using a different ]power supply than the old one). I would suggest that static electricity may be at fault. The CIA is an extremely static sensitive device, and the joystick ports are directly connected. A good way to zap a 64 is to discharge a little static electricity in a joyport.... ]The problem usually manifests itself by the joysticks failing to respond to ]a certain direction or a key on the keyboard failing to operate properly. ]These ICs cost $17 each from Commodore and about twice that locally. Of course.... try mail-order. ]Commodore has no one that I have been able to contact intelligent enough to ]discuss this problem but I'm sure they would deny a problem anyway. My only ]solution is to build a replacement from discrete TTL which technically is ]no problem but I don't beleive the part is explained sufficiently in the ]programmer's manual to premit this. Commodore is obviously no help on ]this either. Don't kid yourself.... Commodore knows that this is a problem. And building a complex device like a CIA from "discrete TTL" would be overkill (not to mention that it wouldn't be physically convenient). -- jgreco@csd4.milw.wisc.edu Joe Greco at FidoNet 1:154/200 USnail: 9905 W Montana Ave PunterNet Node 30 or 31 West Allis, WI 53227-3329 "These aren't anybody's opinions." Voice: 414/321-6184 Data: 414/321-9287 (Happy Hacker's BBS)
jbh@mibte.UUCP (James Harvey) (02/04/89)
In article <435@manta.NOSC.MIL>, mitch@manta.NOSC.MIL (Ray Mitchell) writes: > > Has anyone encountered any problems with repeated failures with the 6526A IC > IC in the C64? I think they call the IC an ACI. The system has two of them > but the one interfacing to the joystick ports and keyboard is the one giving > me the problems. > > I have been through about four of them in the last 2 years and I am ending > up investing more in them than I have in the computer. I even bought a > different computer thinking it might be something in the system but the > new one also blows one about every 6 months (The new C64 is using a different > power supply than the old one). > > The problem usually manifests itself by the joysticks failing to respond to > a certain direction or a key on the keyboard failing to operate properly. > These ICs cost $17 each from Commodore and about twice that locally. > > > Ray Mitchell This is usually caused by static electricity leaping from your finger to a pin on the joystick port when you reach down to turn the C64's on/off switch. I lost two 6526 chips this way (machine was in a room with a wool carpet and low humidity in the winter). My solution was to get some of the adhesive-backed foil tape that radio shack sells for burglar alarming windows. I ran a strip around the joystick port opening and grounded it. The idea is for any static to pick this grounded tape instead of the joystick port. I haven't had trouble since (but my machine is no longer in a carpeted room). JAMCO advertises the 6526 chips a lot cheaper that $17. Check the ads in Byte magazine or COmputer Shopper. -- Jim Harvey | "Ask not for whom the bell Michigan Bell Telephone | tolls and you will only pay 29777 Telegraph | Station-to-Station rates." Southfield, Mich. 48034 | ulysses!gamma!mibte!jbh
jdrew@uoregon.uoregon.edu (James Robert Drew) (02/05/89)
As mentioned, the problem is almost certainly static electricity. I suspect that the grounding foil may be your best bet. Alternatives include buying a 128, which is supposed to be less prone to the problem, and keeping a pair of joysticks plugged in at all times. This latter is what I do with my 128, and I've had no problems since I got it (I got it since my 64 blew the joystick post, got fixed, and blew a memory chip the next week). A note on this: I have heard of the problem arising when the computer is on and the joystick is dropped onto a hard surface. In addition, keeping the computer in a cool, dry (read: low humidity) place should help, too. *********************** Jim Drew (Crd. Xin) I was walking down Wall Street. It seemed jdrew@drizzle.cs.uoregon.edu strange for Wall Street to be so deserted at two o'clock on a Friday afternoon, but, considering what was following me, perhaps it was not so odd after all. I reached in my jacket for the .38 I had holstered that morning, and pulled out...a banana. Indeed, the eighty-foot tall fire hydrant chasing me was to be the least of my worries. - "Marc Lynx," detective ***********************
elg@killer.DALLAS.TX.US (Eric Green) (02/06/89)
in article <435@manta.NOSC.MIL>, mitch@manta.NOSC.MIL (Ray Mitchell) says: > Has anyone encountered any problems with repeated failures with the 6526A IC Static electricity. If you touch the joystick ports in cold weather, or after rubbing your feet against carpet, it will blow up the CIA. Typically, your hand brushes the joystick port on the way towards the power switch, i.e. you don't do it intentionally. This is the biggest cause of computer failures that my local repair center sees -- static-fried CIAs. The solution? Buy a humidifier for your computer room, or do like Jerry Pournelle and take up an aquarium hobby ;-). Or, if you're really technically proficient, put MOVs and decoupling diodes on your joystick ports. -- | // Eric Lee Green P.O. Box 92191, Lafayette, LA 70509 | | // ..!{ames,decwrl,mit-eddie,osu-cis}!killer!elg (318)989-9849 | | \X/ >> In Hell you need 4Mb to Multitask << |
dchen@wpi.wpi.edu (Daniel D.E. Chen) (02/08/89)
It's strange but I recently took a new C64c apart and found much to my dismay the whole circuit board is changed. The MPU, 6581 SID, and 3 ROM were replaced with a large 40 pin MPU, a 6582 SID and 2 ROMS. I also saw something really interesting about the design, there were little capacitor in series with each line of the joystick, probably there to prevent "electricution" of the CIA chips. The board itself got reduced from 5 inches to around 3 inches. Would anyone know what the new MPU is and what is differnt about it? It seems capatible with the 28 pin 6510. Does anyone know I can get the new schematic for it? Daniel Chen ----------------------------------------------------------------------------- Bitnet : DCHEN@WPI.bitnet Internet: DCHEN@WPI.wpi.edu IP : 128.215.32.1 -----------------------------------------------------------------------------
jgreco@csd4.milw.wisc.edu (Joe Greco) (02/09/89)
In comp.sys.cbm article <689@wpi.WPI.EDU>, dchen@wpi.wpi.edu (Daniel D.E. Chen) wrote: ]It's strange but I recently took a new C64c apart and found much to my ]dismay the whole circuit board is changed. The MPU, 6581 SID, and 3 ]ROM were replaced with a large 40 pin MPU, a 6582 SID and 2 ROMS. ] ]I also saw something really interesting about the design, there were ]little capacitor in series with each line of the joystick, probably ]there to prevent "electricution" of the CIA chips. ] ]The board itself got reduced from 5 inches to around 3 inches. ] ]Would anyone know what the new MPU is and what is differnt about it? ]It seems capatible with the 28 pin 6510. Does anyone know I can get ]the new schematic for it? I have NEVER seen a 28 pin 6510.... There are more components than those you listed. If two ROMs are all that exist, I would guess that one is a 16K BASIC/Kernal ROM and the other is the 4K character "generator" ROM. The 6581 and 6582, as I recall, are identical except for some electrical characteristics. What is a "large 40 pin MPU"? The processor has always had 40 pins. What is "large" supposed to mean? -- jgreco@csd4.milw.wisc.edu Joe Greco at FidoNet 1:154/200 USnail: 9905 W Montana Ave PunterNet Node 30 or 31 West Allis, WI 53227-3329 "These aren't anybody's opinions." Voice: 414/321-6184 Data: 414/321-9287 (Happy Hacker's BBS)
warren@hp-col.HP.COM (Warren Tustin) (02/10/89)
/ hp-col:comp.sys.cbm / mitch@manta.NOSC.MIL (Ray Mitchell) / 12:13 pm Feb 3, 1989 / >Has anyone encountered any problems with repeated failures with the 6526A IC >IC in the C64? I think they call the IC an ACI. The system has two of them >but the one interfacing to the joystick ports and keyboard is the one giving >me the problems. >Any suggestions will be appreciated. >Ray Mitchell >---------- I leave my joysticks plugged in and have not had any problems, but if I had, I would probably buffer the joystick ports with some inexpensive TTL 74LS04's or the non-inverting version of above. I have modified the ROM's in my 64 and have replaced a bad ram and also have added a numeric keypad so I'm not afraid to 'dig into' the 64; however adding a simple buffer would protect the CMOS parts from static and should solve your problem. It may involve some cutting on the PC board although you could probably do it externally to the computer if you had a spare joystick plug or two. The simpleler(sp?) solution of metallic tape around the Joystick ports is probably nearly as effective and much easier to implement. Warren Tustin
fred@cbmvax.UUCP (Fred Bowen) (02/10/89)
In article <689@wpi.WPI.EDU> dchen@wpi.wpi.edu (Daniel D.E. Chen) writes: >It's strange but I recently took a new C64c apart and found much to my >dismay the whole circuit board is changed. The MPU, 6581 SID, and 3 >ROM were replaced with a large 40 pin MPU, a 6582 SID and 2 ROMS. The MPU (8500 MPU) is the same as always- it's just a 6510 in new clothes. The SID (6582 aka 8580) is the same except pin 28 (vdd) is now at 9V. The BASIC and kernel ROMs have been merged into one, the character ROM is unchanged. The biggest change is the gonzo 64-pin gate array, which combines much of the TTL glue with the old PLA, and the used of 64Kx4 DRAMs. >I also saw something really interesting about the design, there were >little capacitor in series with each line of the joystick, probably >there to prevent "electricution" of the CIA chips. No, they are EMI filters designed to prevent FCC trouble, not protect the CIA. >Would anyone know what the new MPU is and what is differnt about it? >It seems capatible with the 28 pin 6510. Does anyone know I can get >the new schematic for it? See the description above; sounds like you are confusing the processor with the gate array (aggravated by some serious pin miscounting :-) Service centers are allowed to sell schematics and service manuals if they want. Many are reluctant to do so, fearing competition and/or loss of business I would guess. Still, that the board has changed in what, 6 years, is no reason to be dismayed. -- -- Fred Bowen uucp: {uunet|rutgers|pyramid}!cbmvax!fred arpa: cbmvax!fred@uunet.uu.net tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380
jgreco@csd4.milw.wisc.edu (Joe Greco) (02/10/89)
At some time, Daniel Chen wrote to me: ] In comp.sys.cbm article <827@csd4.milw.wisc.edu>, jgreco@csd4.milw.wisc.edu ( Joe Greco) write: ] > I have NEVER seen a 28 pin 6510.... ] ] > What is a "large 40 pin MPU"? The processor has always had 40 pins. ] > What is "large" supposed to mean? ] ] I mean to correct myself. a 80 pin MPU in the new 64c. forty pin on ] each side of the chip. I still doubt that. I've never heard of an 80-pin chip. I've seen 64 (?), I believe my old 1700 had one. But I don't think our friends at Commodore would mess around with the processor. Logically, the PLA would be the place to expand. Most of my newer 64's have relatively little TTL support circuitry, and I would hazard a guess that Commodore has released a new superPLA. One earlier model 64c I ran into had 64Kx4 DRAM chips, and I would suspect later releases also do. As I already suggested, IF there are only two ROM chips, I'd guess that one is the character "generator" ROM and the other is a 16K combined BASIC/Kernal. If so, damn Commodore since I don't want to muck around burning 16K EPROMs. I am keeping in mind that Commodore has been known to do wierd things. So I am not saying that you're not right, just that you might want to doublecheck. ] Well on the part of the 6581 and 6582 sid chips, I got a second 6581 ] sid chip and was ready to make a piggy-back board to put the second ] 6581 chip into place to make it play 6 voices. i.e. Stereo ] Sidplayer. I was surprise to find that I had to buy a 6582 at $2 ] more. ] ] Has anyone put together a 6 voice C64? For a while, one authorized service shop was sending people to ME to do such a modification "for cash".... intereresting, since I've never done the actual modifications and don't really have great facilities. Oh well.... The stereo chip can be a nice addition, if well programmed. That's the trick.... it's useless without software. The difference between the 6581 and 6582 is, as I said, something about electrical characteristics. I believe the 6582 operates at 9v instead of 12v.... or something.... sleep. I need sleep. -- jgreco@csd4.milw.wisc.edu Joe Greco at FidoNet 1:154/200 USnail: 9905 W Montana Ave PunterNet Node 30 or 31 West Allis, WI 53227-3329 "These aren't anybody's opinions." Voice: 414/321-6184 Data: 414/321-9287 (Happy Hacker's BBS)
hermit@ssyx.ucsc.edu (William R. Ward) (02/12/89)
In article <854@csd4.milw.wisc.edu> jgreco@csd4.milw.wisc.edu (Joe Greco) writes: >At some time, Daniel Chen wrote to me: >] In comp.sys.cbm article <827@csd4.milw.wisc.edu>, jgreco@csd4.milw.wisc.edu ( Joe Greco) write: >I am keeping in mind that Commodore has been known to do wierd things. >] sid chip and was ready to make a piggy-back board to put the second >] 6581 chip into place to make it play 6 voices. i.e. Stereo >] Sidplayer. I was surprise to find that I had to buy a 6582 at $2 >] more. >] >] Has anyone put together a 6 voice C64? > >For a while, one authorized service shop was sending people to ME to >do such a modification "for cash".... intereresting, since I've never >done the actual modifications and don't really have great facilities. >Oh well.... > >The stereo chip can be a nice addition, if well programmed. That's >the trick.... it's useless without software. There is a standard for stereo SID in the C64/128. StereoPlayer is a SIDplayer extension which plays two SIDplayer format songs at once, one on each chip (FOO.MUS = left, FOO.STR = right). There are many songs which have been made stereo and posted on QuantumLink, and StereoPlayer now supports the Enhanced SIDplayer and soon MIDI. It is up to version 10.0 (MIDI is 11.0) and is public domain. In my estimation, and that of several other Commodore users I know, the StereoPlayer program is, without a doubt, the best music player available for the C64/128. -- Bill (William R.) Ward hermit@ssyx.ucsc.edu QuantumLink: TheHermit1 -- If creative thoughts could cause sparks, dynamite could safely be stored in this establishment. William R. Ward <hermit@ssyx.ucsc.edu>