williamm@tramp.Colorado.EDU (Michael Williams) (04/29/88)
Okay, I am in a very harsh bind here: Neither my ][+ nor my //e
will startup correctly, and I am not desiring to pay $80 for a techie
to take off my lid and replace a $1 chip from an obvious failure.
The problem is...it isn't obvious to me (so that's what they get
paid for, I know...). Both problems are fairly close, but not exact,
so here they are:
][+ : It was given to me dead, so I am not sure what the immediate
cause of failure was. When the machine is turned on, no card
is accessed (not the disk controller at least), and the screen
has a static display of '?'s, ' 's, and 'F's. Nothing else.
I am pretty sure that the power supply has nothing to do with it
(for I replaced it temporarily with a good one).
//e : I saw this one bite it. I was playing a game and was pulling
a loose joystick cable out from the machine (it was not plugged
in, but just sitting there looking stupid) when ALAS, my screen
became filled with columns alternating between normal and inverse
spaces (rows of black and white). Turning the machine off and then
(not immediately) back on resulted in the same lovely pattern,
and when the disk controller was in place, the SECOND drive would
start spinning until I did a RESET. The self-diagnostics test
only caused a temporary additional patter to be spit to the the
screen. ----BTW, this is (was? :-( ) unenhanced.
With both of these machines I have removed all cards so as to at least
pinpoint it to the motherboard (pretty specific, eh?). Also, I have
checked the power supplies, and they are both appearing okay. My guess
is that it has to do with the AutoStart ROMS, but it could be the 6502.
Any suggestions as to what to check? What could have gone wrong?
Which ROM (if so) ? Or even a good troubleshooting book?
PLEASE help me get these (at least the 'e) back onto their feet.
Thanks much in advance for any and all help,
Remo
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..{nbires,ncar,seismo,ihnp4}!boulder!tramp!williamm \ Bela Lugosi riding the
BIT: WILLIAMS_MS%CUBLDR@VAXF.COLORADO.EDU / Kundalini Express in ...
SNAIL: 2905 E Aurora Ave #129, Boulder CO 80303 \ (could it be?) Sunshine!williamm@tramp.Colorado.EDU (Michael Williams) (04/29/88)
Well, today I replaced all of the ROMS , the CPU, the MMU, and the
IO unit of the //e. Still, no go. In addition, I replaced each of the
RAM chips. This resulted in a change of the pattern seen on the
screen, but that is it. I replaced a little bit of the LS, but
still need to finish with those; I have about 5 more to replace
before I have gone through each IC on the motherboard.
Any suggestions as to what might go wrong besides an IC??
Thanks,
Remo
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..{nbires,ncar,seismo,ihnp4}!boulder!tramp!williamm \ Bela Lugosi riding the
BIT: WILLIAMS_MS%CUBLDR@VAXF.COLORADO.EDU / Kundalini Express in ...
SNAIL: 2905 E Aurora Ave #129, Boulder CO 80303 \ (could it be?) Sunshine!williamm@tramp.Colorado.EDU (Michael Williams) (04/30/88)
In article <5730@sigi.Colorado.EDU> williamm@tramp.Colorado.EDU (Michael Williams) writes: >Well, today I replaced all of the ROMS , the CPU, the MMU, and the >IO unit of the //e. Still, no go. I must have replaced one of the chips improperly, for I again tried the MMU and this time it worked. For the //e, the cause of all of the problems was a dead MMU, *FLAME* which is now going to cost me $40 (retail) to replace!! I can get it for $10 less at wholesale, but this is still ridiculous. ROMS cost $40 wholesale. A 256x8 PROM for a Communications card is going to cost $45! That is 256x8, NOT a 256Kx8!! This really urks me that Apple is so proud of their proprietary ROMs that they think they can sell them for so much. Just because they are selling antique ROMS doesn't mean that they have to charge antique prices!!! *EMALF* I did some checking on the ][+ and am pretty sure that it is either the 6502 or the EF ROM which is causing the problems. Hopefully it is the 6502, for I can replace that at less than 10% the cost of the ROM (retail). I will update when I find out. BTW, referring to my earlier ROM flame- I seriously AM trying to get ahold of a few ROMS if somebody has them for sale: the PROM used in the Communications Interface, the 2 PROMS used in the (non-Super) Serial Interface. Mail me, if so... Remo ------------------------------------------------------------------------------ ..{nbires,ncar,seismo,ihnp4}!boulder!tramp!williamm \ Bela Lugosi riding the BIT: WILLIAMS_MS%CUBLDR@VAXF.COLORADO.EDU / Kundalini Express in ... SNAIL: 2905 E Aurora Ave #129, Boulder CO 80303 \ (could it be?) Sunshine!
neighbor@csd4.milw.wisc.edu (Jeffrey Alan Ding) (05/03/88)
In article <189@studsys.mu.edu> jetzer@studsys.mu.edu (jetzer) writes: >We had a similar problem with a ][+. It seems that just pressing down >on any chip near the back right corner of the motherboard made it work >properly, for about 5 minutes. Made me think that some of the chip/socket >connections were corroded or something. But, ][+'s have a very low priority, >and we had an extra (good) motherboard laying around, and swapped it. > Type pulling out all the chips on the motherboard and put them back in. This will break all the corroded contacts might solve the problem. >Also had a similar problem with a couple of //e's at various times. Once >someone tried to plug in a joystick, but the disk controller was in the >way ... so he removed the card from the slot (while the power was still >on!). Same type of mess, although it was usually lores graphics. Swapped >every chip on the motherboard, and determined that one of the RAMs was bad. >Surprised me that a bad RAM would do this, but ... > I don't see how a bad RAM was the trouble. If you pull out a card while the power is on you risk damaging the card, not the computer. But I don't doubt the computer got messed up. >Another time someone in the electronics class was making an interface >card for a robot arm. Got two wires mixed up, and fried the //e (they >now use ][+'s in the robotics class :-). What was really interesting I would like to know which two wires. It is pretty hard to fry the motherboard on an Apple computer. If you directly short out the power supply by mistake, it will shut down and nothing will get damaged. Any other of the wires on the connector will only cause the computer not to work. Turn the power off, take the card out, and turn the power back on and the computer should work just fine. The problems occur when you forget to turn off the power to take out and insert cards. >Mike Jetzer >"Hack first, ask questions later." neighbor@csd4.milw.wisc.edu _______________________________________________________________________________ | arpanet: neighbor@csd4.milw.wisc.edu | | UUCP: ihnp4!uwmcsd1!csd4!neighbor | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jetzer@studsys.mu.edu (jetzer) (05/03/88)
In article <5718@sigi.Colorado.EDU>, williamm@tramp.Colorado.EDU (Michael Williams) writes: > ][+ : It was given to me dead, so I am not sure what the immediate > cause of failure was. When the machine is turned on, no card > is accessed (not the disk controller at least), and the screen > has a static display of '?'s, ' 's, and 'F's. Nothing else. > I am pretty sure that the power supply has nothing to do with it > (for I replaced it temporarily with a good one). > //e : I saw this one bite it. I was playing a game and was pulling > a loose joystick cable out from the machine (it was not plugged > in, but just sitting there looking stupid) when ALAS, my screen > became filled with columns alternating between normal and inverse > spaces (rows of black and white). Turning the machine off and then I work for a school district over the summer, and do *simple* repair type stuff. We had a similar problem with a ][+. It seems that just pressing down on any chip near the back right corner of the motherboard made it work properly, for about 5 minutes. Made me think that some of the chip/socket connections were corroded or something. But, ][+'s have a very low priority, and we had an extra (good) motherboard laying around, and swapped it. Also had a similar problem with a couple of //e's at various times. Once someone tried to plug in a joystick, but the disk controller was in the way ... so he removed the card from the slot (while the power was still on!). Same type of mess, although it was usually lores graphics. Swapped every chip on the motherboard, and determined that one of the RAMs was bad. Surprised me that a bad RAM would do this, but ... Another time someone in the electronics class was making an interface card for a robot arm. Got two wires mixed up, and fried the //e (they now use ][+'s in the robotics class :-). What was really interesting was that it gave 80 columns of garbage, even though there was no 80-col card in it at the time. This one was an enhanced motherboard, and all the RAMs were soldered in. Had to send this one out, and when it came back, one RAM and another chip (sorry, don't remember which one) were replaced. Hope this helps -- Mike Jetzer "Hack first, ask questions later."