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8032 new issue ? help?

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polishedball

Experienced Member
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Mar 21, 2010
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114
Just had an 8032 loose keyboard input when a 8050 drive was connected to it (not hot was connected prior to power up) It then proceeded to loose the blinking cursor on the next reboot after reseating chips. It chirps correct, displays basic 4.0 and memory correct. Just no cursor and no key input. Ideas?

John
 
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I have swapped the 6545, 6520's and 6522 same issue. It reports the memory as good, wondering where to start looking now. This is an early 8032030 revision board. Not a universal.
 
dave_m said:
If the 8050 disk is not connected via IEEE488 cable, all is well?
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Sorry, to clarify, never had the problem until I hooked up the drive. Now the problem exists with the drive disconnected also. Perhaps it was coincidence and they are unrelated but it happened when connected for the first time. The 8050 is also an unknown and I am now scared to hook it to another working pet. I just got done repairing the control board in it and it now passes self test on boot, but have never used it before.

The pet has no cursor right now by itself with no accessories connected.
 
dave_m said:
See if you can at least come up in the monitor program by grounding pin 5 on the user port (J2) prior to power up.
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Nope it comes up to the same screen, but the audible start up chirps are not there.
 
My first bet would've been the 6522 but as you have swapped it with a known good chip, I suppose not. I have found those chips can go partly bad, meaning some of its functions will still be OK while some functions are broken. Thus a chip you may think is 100% in practise is only 75% but the application where you use it doesn't utilize the broken funcs.
 
I concur with carlsson as I had a 6522 that worked fine in a VIC 20 (or appeared to work fine) but in a pet it caused problems.

Have you got a working pet/VIC 20 to swap one out of to test.
 
Pet Rescue said:
I concur with carlsson as I had a 6522 that worked fine in a VIC 20 (or appeared to work fine) but in a pet it caused problems.

Have you got a working pet/VIC 20 to swap one out of to test.
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I have swapped it with a 6522 from a working 8032 and still have the same issue. Thanks
 
The resistor pack is good, swapped the BCD to Dec chip, still the same no blinking cursor and no response to holding a key down to look for end of row sound.

Gonna take a look at the EOI since it run through this chip, maybe the small circuitry got damaged or fatigued when I connected a drive.

It is not the 7417 in the EOI signal chain.
 
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Also just tested the roms all are good. If there is a zeropage memory type error could this cause this? And still have it report all memory as good? Which ram chip if so correlates to that area under basic?
 
polishedball said:
If there is a zeropage memory type error could this cause this? And still have it report all memory as good? Which ram chip if so correlates to that area under basic?
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Actually, yes there could be bad memory cells in zero page and the system could report 32K because the memory test starts at address $401, the start of BASIC.

Any of the 8 lower 16K RAM chips may be bad. Too bad you can't get into the monitor program to find the bad bit. I am puzzled by the inability to get to the monitor code if the ROMs are good and the 6520's are good.
 
dave_m said:
Actually, yes there could be bad memory cells in zero page and the system could report 32K because the memory test starts at address $401, the start of BASIC.

Any of the 8 lower 16K RAM chips may be bad. Too bad you can't get into the monitor program to find the bad bit. I am puzzled by the inability to get to the monitor code if the ROMs are good and the 6520's are good.
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Yep, that sure helped alot with the fat 40 to get it ID'd.

Any other ideas or should I just socket out the lower RAM next?
 
polishedball said:
Yep, that sure helped alot with the fat 40 to get it ID'd.

Any other ideas or should I just socket out the lower RAM next?
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Wow, that's a lot of work. I forget, do you have a scope?

If not, and you can program a 2532, you might consider putting a RAM test in the F000 socket and report the answer on the user port.
 
polishedball said:
Yes I have a scope, an old TEk 465.
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Well then a good troubleshooting step may be to use MikeS' NOP generator:

And although it's usually ignored I'm gonna suggest again that one of the most useful "tools" is a NOP generator, nothing more than a 40pin socket with pins 26-33 cut/lifted to isolate them from the board and connected to the CPU with Vcc and Gnd thusly: 11101010(EAh) for fetching only NOP instructions.

Inserted between the CPU and its socket this will continuously step through the address range (64K) and with a scope you can quickly identify bad address drivers, memory or I/O chips pulling address or data lines high or low, etc.

If power is good and the ROMs check out this is what I usually check next and more times than not it locates a problem.
Click to expand...
 
dave_m said:
Well then a good troubleshooting step may be to use MikeS' NOP generator:
Click to expand...

Thanks is there a detail thread, or am I correct in saying i wire 26-33 to logic high or low to make 11101010 once they are isolated from the board?
Thanks!

Also looking for opinions could hooking up the 8050 have done this or would you bet coincidence? Really want to know if i have it (8050) fixed but don;t want to be down another pet.
 
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polishedball said:
Thanks is there a detail thread, or am I correct in saying i wire 26-33 to logic high or low to make 11101010 once they are isolated from the board?
Click to expand...
yes, pin 26 is MSB (D07)

Also looking for opinions could hooking up the 8050 have done this or would you bet coincidence? Really want to know if i have it (8050) fixed but don;t want to be down another pet.
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It is hard to see how a fault on the IEEE bus can kill the pet when disk drive is removed especially since you checked the EOI signal and it is not shorted.
 
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