chad@byuvax.bitnet (02/10/88)
I just finished putting in sockets, the capacitors, and 2 resistors
on my 520STfm motherboard (rev D) where it normally is in a 1040.
Now, with or without the sockets populated, you turn the machine on, it
displays that typical blank screen for boot but with a white stripe
going across it about 2/3 or 3/4 of the way down from the top
----------------
++++++
+++++++++++
----------------
with some dark pixels on the bottom of the stripe. When one turns it off
and on again, one gets rows of a dark pixel pattern (blotches in a pattern)
on this same screen. (Guess that the video RAM gets junk in it.)
The disk drive is NOT accessed. It just sort is dead. I've looked at all
the traces on the board, can't see anything shorted, etc.
Any suggestions?
Thanks,
Chad
BITNET: Chad@Byuvaxrich@lakesys.UUCP (Rich Dankert) (02/13/88)
In article <113chad@byuvax.bitnet> chad@byuvax.bitnet writes: > >I just finished putting in sockets, the capacitors, and 2 resistors >on my 520STfm motherboard (rev D) where it normally is in a 1040. Two --> resistors ??? <-- I just completed a 520STfm upgrade. Used sockets, caps and of course chips. No resistors though. Where did you put the resisors ??? I also did the upgrade on a Rev D board. > >Now, with or without the sockets populated, you turn the machine on, it >displays that typical blank screen for boot but with a white stripe >going across it about 2/3 or 3/4 of the way down from the top > Sounds like you ZAPed someting while you were working on the upgrade. I would look into the MMU if I were you. You may have toasted it. Sounds like what your seeing is some words placed on the screen. A friend of mine had this with his upgrade board, and the problem WAS the MMU. Replaced and allis fine. -rich UUCP: {Ihnp4,uwvax}!uwmcsd1!lakesys!rich Discalimer: The words,ideas,and expressions are my own, and not nessasarily always correct, so don't hold me to it!
chad@byuvax.bitnet (02/15/88)
About the resistors. The people (many) who gave me instruction on how
to do it all mentioned resisitors needing to be put in. On the REV D
board there are 4 68-69ohm resistors as follows
-***-
-***-
-***-
-***-
and then 9 or so 330ohm
-***-
etc.
The two I put in were in that space there in the 4 and underneath the 4
68-69 ohm type. We looked at a 1040STf REV B board (which is totally
laid out on the board differently -- RAM, not ROM under power supply,
CPU not on right, etc.) and it two had 6 (not 4) 68-69 ohm resiistors
and 9 or so 330 ohm resistors with the RAM. Someone told me the resistors
are there to be nice to the MMU chips and that some early 520 ST models
didn;t have them but they do now.
We are going to first try reseating the MMU and then try to get one.
(anybody have one cheap???)
Chad
Disclaimer: I am not a lawyer, never was, never will be, so don't
sue me -- I ain't got no money.franco@iuvax.cs.indiana.edu (02/19/88)
Be careful with the resistors! Some memory chips like the Hitachis get screwed up with them. Others, like the NEC, need them badly. My upgrade has been performing fine for 2 years with no resistors (Hitachi DRAMS).
lharris@gpu.utcs.toronto.edu (Leonard Harris) (02/21/88)
In article <36500032@iuvax> franco@iuvax.cs.indiana.edu writes: > >Be careful with the resistors! Some memory chips like the Hitachis get >screwed up with them. Others, like the NEC, need them badly. My upgrade >has been performing fine for 2 years with no resistors (Hitachi DRAMS). Also - be careful as to the make of memory chips. Samsung and OKI definately will not work !! /leonard
dragon@olivej.olivetti.com (Give me a quarter or I'll touch you) (02/23/88)
in article <1988Feb20.165200.1213@gpu.utcs.toronto.edu>, lharris@gpu.utcs.toronto.edu (Leonard Harris) says: > Also - be careful as to the make of memory chips. Samsung and OKI definately > will not work !! > /leonard Oh, come on now. I've done quite a few upgrades with Samsung and OKI chips. I should add, the only one that ever went bad had Samsung chips. For that reason, I stay away from them. But they certainly will work. One should also be using 120ns chips, as a precaution. The newer STs have been outfitted with these (for a reason, I would imagine, if not only because Atari could get a better price on them than 150ns). --Dean ---- Dean Brunette {ucbvax,etc.}!hplabs!oliveb!olivej!dragon {ucbvax,etc.}!oliveb!olivej!{dragon-oatc,lobster}!dean Olivetti Advanced Technology Center _____ _____ __|__ _____ 20300 Stevens Creek Blvd. | | _____| | | Cupertino, CA 95014 |_____| |_____| |__ |_____ 'Dancing, screaming, itching, squealing, fevered feeling hot Hot HOT!'
lharris@gpu.utcs.toronto.edu (Leonard Harris) (02/25/88)
In article <15691@oliveb.olivetti.com> dragon@olivej.olivetti.com (Give me a quarter or I'll touch you) writes: >in article <1988Feb20.165200.1213@gpu.utcs.toronto.edu>, lharris@gpu.utcs.toronto.edu (Leonard Harris) says: > >> Also - be careful as to the make of memory chips. Samsung and OKI definately >> will not work !! >> /leonard > >Oh, come on now. I've done quite a few upgrades with Samsung and OKI >chips. I should add, the only one that ever went bad had Samsung chips. >For that reason, I stay away from them. But they certainly will work. One >should also be using 120ns chips, as a precaution. The newer STs have been >outfitted with these (for a reason, I would imagine, if not only because >Atari could get a better price on them than 150ns). > >--Dean > > >---- >Dean Brunette {ucbvax,etc.}!hplabs!oliveb!olivej!dragon > {ucbvax,etc.}!oliveb!olivej!{dragon-oatc,lobster}!dean > >Olivetti Advanced Technology Center _____ _____ __|__ _____ >20300 Stevens Creek Blvd. | | _____| | | >Cupertino, CA 95014 |_____| |_____| |__ |_____ > >'Dancing, screaming, itching, squealing, fevered feeling hot Hot HOT!' I'm not the only one who has problems with samsung memory. Ask around. Why do you think these are the cheapest on the market - because they bought the masks to older technology parts. I'd rather have NEC, or hitachi stuff in my machine. By the way - why did the upgrade with samsung parts fail ? (I have nothing against Korean made parts - I just find japanese and american more reliable !) /leonard
lharris@gpu.utcs.toronto.edu (Leonard Harris) (02/25/88)
The reason for putting 68 ohm resistors on the CAS lines is due to the lack of an efficient ground plane on the ST. The resistors are there to reduce ringing on these lines which causes the memory to be "double-clocked" - ie. think valid data is there when it isn't. A better idea would have been to actively terminate these lines, but a series resistor is cheaper and seems to work. (note: this is a reason many 4 meg add on boards don't work when fully loaded on the ST - they are too noisy and CAS gets confused) /leonard
leigh@byuvax.bitnet (02/26/88)
The problem is now gone, a friend of mine took everything (RAM) off and looked around and found a mysterious short or some such thing. I used 100 ns OKI chips (work fine) and 120ns Mitsubishi (? no name only a small symbol of some sort -- looks like miits). Thanks for the help.
dragon@olivej.olivetti.com (Give me a quarter or I'll touch you) (02/26/88)
in article <1988Feb24.191400.15905@gpu.utcs.toronto.edu>, lharris@gpu.utcs.toronto.edu (Leonard Harris) says: > In article <15691@oliveb.olivetti.com> dragon@olivej.olivetti.com (Give me a quarter or I'll touch you) writes: >>in article <1988Feb20.165200.1213@gpu.utcs.toronto.edu>, lharris@gpu.utcs.toronto.edu (Leonard Harris) says: >>> Also-be careful as to the make of memory chips. Samsung and OKI definately ^^^^^^^^^^ >>> will not work !! >>> /leonard >>Oh, come on now. I've done quite a few upgrades with Samsung and OKI >>chips. I should add, the only one that ever went bad had Samsung chips. >>For that reason, I stay away from them. But they certainly will work. One > I'm not the only one who has problems with samsung memory. Ask around. > Why do you think these are the cheapest on the market - because they > bought the masks to older technology parts. I'd rather have NEC, or > hitachi stuff in my machine. By the way - why did the upgrade with > samsung parts fail ? > (I have nothing against Korean made parts - I just find japanese and american > more reliable !) > /leonard I agree with the fact that the American and Japanese parts are far superior, but you bluntly stated that the Samsung chips won't work. And they do! The reason the upgrade failed was ram chip failure (of course!). Of course you aren't the only one who has had problems, why should I ask when it has happened to me? I answered all the questions you asked before you asked them. And NEC and Hitachi are among my least favorite of Japanese parts - I prefer Toshibas for Japanese and TI for American. But with the prices now, it's almost cheaper to get static ram. --Dean ---- Dean Brunette {ucbvax,etc.}!hplabs!oliveb!olivej!dragon {ucbvax,etc.}!oliveb!olivej!{dragon-oatc,lobster}!dean Olivetti Advanced Technology Center _____ _____ __|__ _____ 20300 Stevens Creek Blvd. | | _____| | | Cupertino, CA 95014 |_____| |_____| |__ |_____ 'Dancing, screaming, itching, squealing, fevered feeling hot Hot HOT!'