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View Full Version : My 8032 woes please advise



polishedball
March 22nd, 2010, 05:18 PM
I recently got out my 8032 and figured i'd do some board work had 3 (8032 MB) to repair. I turned it on got the normal beeps warble screen displayed an odd 7K of ram then died lost display. On reset it was stone dead.

I replaced the 6520(2), 6502, 6522, 6545, the character, kernal, edit, and basic roms.. (yes I have alot of spare parts. The unit now beeps as normal but has no display. I swapped in another baord I had not knowing the status of it and got a dot in the center of the screen so I assume the monitor to work still. Ok back to my original board.

I am thinking the DRAM's might be causing me trouble not allowing basic to post and since I had the odd ram reported when it did come up the first time. Ideas? or thoughts. I think i'll start socketing all my DRAMS now. I love my Hakko 808 for these old boards.

I have verified the voltage 20v going to the monitor the heaters glow, The +5, +12, and -5 are all there.

Thanks in advance for any help.

tezza
March 22nd, 2010, 06:32 PM
Just to clarify, replacing the ICs mentioned did improve matters yes? Prior to that there was no sign of life at all?

I wonder if the video RAM may have gone completely, along with a ROM IC (which you've now replaced)? At least it beeped which showed it booted up to some degree anyway? In my experience hung DRAM usually leaves garbage on the screen but there might be occasions when it doesn't.

Tez

polishedball
March 22nd, 2010, 08:29 PM
I replace all the DRAM and SRAM; the only SRAM I had was 9114 which I think is a suitable replacement for 2114. Anyhow made some different beeping noise then I had some garbage on the screen only an inch wide taking up the center. It then lost the screen again.

Is there a simple poke command to make it beep so I can see if it is a main board problem or a monitor issue?

Thanks , open to all ideas.

John

polishedball
March 22nd, 2010, 09:17 PM
I just re capped the board in case it had something to do with the oddities I am getting. This is where it stands sometimes I can hit the power switch and get a quicker 4 chirp, sometimes a longer more melody, and sometimes no sound and a small line in the center of the crt. Anytime it beeps nothing is displayed on the crt sometimes when it makes no noise the crt get small line in the middle and then fades out.

polishedball
March 22nd, 2010, 09:35 PM
Here is a link to the audio file of what the beeps sound like. It has been so long I don;t remember what normal is. I hit the power switch between the first 2 noises, then had to try awhile to get another been out of it by banging the power switch.

http://home.comcast.net/~polishedball/Memo.m4a

polishedball
March 22nd, 2010, 09:40 PM
Just to clarify, replacing the ICs mentioned did improve matters yes? Prior to that there was no sign of life at all?

Tez

It seems to have improved though I might not have played with it enough. It appeared dead, but sometimes in its current state it acts the same way. Puzzled. If you have time please listen to the audio I posted, the level is super low I only had my cell to record it with, but pretty sure you'll be able to make out the noise. The first 2 flips of the switch made the two distinct different beeps, it then took almost a minute to get another beep.

MikeS
March 22nd, 2010, 10:35 PM
Is there a simple poke command to make it beep so I can see if it is a main board problem or a monitor issue?

Thanks , open to all ideas.

JohnAssuming the keyboard is OK (they often need a good cleaning) just hold a key down for 6 or 7 seconds; it should beep when you reach the right margin. Or type ?CHR$(7)

The reset (and startup beep) can be fussy; a noisy main switch or not waiting long enough between power off and on can cause an incomplete reset. Wait 4 or 5 seconds and then flick the switch decisively.

Is this all with the same monitor? Sure sounds like it could be the monitor; have you checked the cable where it connects inside the monitor? Two of mine were intermittent there; also check the main power connector from the transformer.

polishedball
March 23rd, 2010, 05:06 AM
Assuming the keyboard is OK (they often need a good cleaning) just hold a key down for 6 or 7 seconds; it should beep when you reach the right margin. Or type ?CHR$(7)

The reset (and startup beep) can be fussy; a noisy main switch or not waiting long enough between power off and on can cause an incomplete reset. Wait 4 or 5 seconds and then flick the switch decisively.

Is this all with the same monitor? Sure sounds like it could be the monitor; have you checked the cable where it connects inside the monitor? Two of mine were intermittent there; also check the main power connector from the transformer.

Same monitor, I only have the one. Can anyone tell me is the circut to make composite video on for the 2001 valid for the 8032. Can I use the drives and signal to a 4011 and 4066 to make composite video on a 8032? Perhap I should do this if possible to rule out the monitor. Thanks

carlsson
March 23rd, 2010, 05:49 AM
Actually I tried to build a circuit to get composite video from a PET. I only had partial success. My 40 column boards (3000/4000 series) returned a blurry image without sync but one could identify what it said. My 80 column boards (8000 series) only generated mush, probably due to other sync rates.

From what I know there are at least three or four completely different circuits how to tame the video output. The one I chose was an old design optimized by Andre Fachat (IIRC) for better results. Your milage may vary, but I think you need a rather good multisync monitor to get a steady image, or a different converter circuit.

polishedball
March 24th, 2010, 03:35 PM
Good news is I was able to get one of my boards repaired, and video out though bad on the original board. I have another odd question but will start a new topic.