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Need help to get My pet 4016 work !

Try removing the 2 large 6520 chips, they look like they're soldered in your earlier pictures though. 6520's are not needed to boot to the BASIC prompt. Several times I have had a PET that wouldn't boot because one of these was faulty.

I'd suspect the ROM's next, if there was something wrong with the screen or the CRT chip you would probably still get the chirp sound when you turn it on. Do you have access to an EPROM burner? Or another PET with BASIC 4 ROM's?

Again looking at your earlier pictures most of the ROM's look to be soldered onto the main board so you may have to do some soldering to fix this one. On my none-working 4032 I ended up removing all the soldered ROM's, CRT chip and both 6520's and put sockets in.
 
Hi dansretropod

Thanks for reply, and sorry for delay ! I had a lot of things to do ! we can not always spend time on our leisure :(

Try removing the 2 large 6520 chips, they look like they're soldered in your earlier pictures though. 6520's are not needed to boot to the BASIC prompt. Several times I have had a PET that wouldn't boot because one of these was faulty.

In fact they were soldered ! I removed them like you suggest with no results ! by the way i socket them .

I'd suspect the ROM's next, if there was something wrong with the screen or the CRT chip you would probably still get the chirp sound when you turn it on. Do you have access to an EPROM burner? Or another PET with BASIC 4 ROM's?

I do not have a beep on boot ! I have acces to an eprom burner ! where can i found images of the rom's ? I do not own any other pet !:(

Kind regards, Techtatan
 
Hello Techtatan,

It's probably a good idea to leave the 2 6520's out of your PET until you have managed to boot to the BASIC prompt, 1 of them may still turn out to be faulty.

All the BASIC 4 ROM's can be found here:

http://www.zimmers.net/anonftp/pub/cbm/firmware/computers/pet/index.html

basic-4-b000.901465-19.bin
basic-4-c000.901465-20.bin
basic-4-d000.901465-21.bin
edit-4-40-n-50Hz.901498-01.bin (edit-4-40-n-60Hz.901499-01.bin if your PET is 60hz)
kernal-4.901465-22.bin

The above should be the ROM's you need, though check first with whats already in your PET.
 
hi again

thanks for quick reply :p

Just for to be sure what kind eproms should i use ?
is it possible to get the orginal roms today ? if yes do you know where ? (in case i prefere to have an orginal setup for collection reasons)

kind regards, techtatan
 
Yeah sure, I've used 2532 EPROM's before in my 4032 with no problems, there are probably other types you can use too.

I get all my EPROM's from ebay at reasonable prices and there's usually always some for sale.
 
Sorry, should have mentioned, check your EPROM programmer can write to 2532's, I'm lucky that mine can, but a lot of programmers cannot.
 
hi again

thanks for the tipp ;)

Sorry, should have mentioned, check your EPROM programmer can write to 2532's, I'm lucky that mine can, but a lot of programmers cannot.

i will scheck what i can burn and what eproms i already own !

is it possible to get the orginal mos roms today ?

kind regards, techtatan
 
is it possible to get the orginal mos roms today ?
I doubt you will find the original MOS roms today. Other than salvaging some from other (broken) PET's I have never seen any for sale. It's easier and cheaper to use EPROM's.
 
Hi Techtatan,

I've never used a 2516 in a PET before, I think it would only work in the Edit ROM socket (901498-01 I think) as that ROM is a 2KB ROM, I've used a 2716 in an Edit ROM socket before. All the other ROM's are 4KB so you need a 2532 for those as 2516's are too small.
 
Dan is correct: the only place a 2 kB 2516 (or 2716) would be useful is in the E ROM and the Character Generator locations. For the other ROMS you will need at least a 4 kB chip; the 2532 is a direct replacement but you could also use a 2732 or larger with a fairly simple adapter.

What you could do with the 2516 is burn a small diagnostic ROM, insert it in one of the empty sockets, and by cutting and adding a jumper relocate that socket to the F ROM area.

Another thing that's often useful is a 'NOP generator', basically a 40-pin socket that goes between the 6502 and its socket and tells the CPU to repetitively step through all 65536 addresses so you can check the corresponding address pins on all the memory and I/O chips to make sure the signals get there and are correct.

Read some of the other threads about repairing dead PETs.

And you still haven't said where those chips with the wires are in the schematics.
 
Hi everybody

Sorry to be that late replying to my thread !
But in 2012 i had a motorcycle accident that keept me away from my passions.
Also i was waiting a long time for my PETVET.
I would like to apologize to the people who have followed this post and who have generously volunteered their time to help me !
Thank you all very much !

So finally Due to this Greate tool Called Petvet I was able to identify some Bad RAM chips.
Now the PET starts up normally and every thing seems to work.

There is still some garbage by doing a screen memory dump using the petvet in BYPASS mode, But at this point i can not tell if it had to do whit some compatibility problems with ne new ram chips or if there is some other problem on the mother board ?

as regards the so-called brown wires i still need to find out what these are doing there.
But since 2012 I have acquire a PET 4032 so this will give me some reference to compare.
I will leave feedback as soon i found some time (hope this week-end).

Any way thanks again for all your kind help.

kind regards
 
Hi techatan

I read this thread with a great deal of interest as your PET seems to be having similar problems to mine. I'd upgraded it from 16 to 32k and it stopped working. In the end, it turned out to be a number of damaged chips and a broken track on one of the RAM banks. Finding these problems took patience, a careful reading of the schematics (matching the ICs on the diagrams to the board) and a cheap logic probe. In my case, as it turned out, an oscilloscope wasn't needed, as I could trace the signals through the PET's main board easily enough, once I'd got familiar with the layout.

You can read about it here: http://www.vintage-computer.com/vcforum/showthread.php?41167-PET-3016-memory-upgrade

Cheers

JonB
 
Hi JonB

By reading through my post you must have notice that the board was modified.
It seems that the person who does the modifications knows what he did because it works. but it does not match to another board of 4032 or may there are differences between the boards.
any way i remooved the modifications (brown wires) and reconnect the IC's to the motherboard like it should be and it works too.
So I can't tell at this point why these modifications was made still need to catch them on shematics (but it is not easy for me).

Kind regards
 
hi JonB

that's what I also thought at the beginning :)
but this computer returns from afar, because of a broken video assembly board, a modified motherboard and I do not know how much dead RAM's.
thereby repairs were quite difficult.

At this stage the pet seems to work fine.
I contacted bitfixer for the issue whith garbage in memory dump from PETVET, hope to get some news :)

I'im still out to check chematics in order to understand the modifications made on the boards.
If someone has the courage to help me in this spot, he will be welcome :)

Kind regards, techtatan
 
hi everybody

i had made some RAM test using pet_cbm ram test.prg
Somewhere around cycle 250 of 99999 passed it returns U1

Does anyone know what this means ?

kind regards, techtatan
 
hi

some one knows or have documentations about pet_cbm ram test ?

regards

I have a lot of experience with Commodore PETs but I have never heard of this program. How are you loading the program? Is it one a diskette or tape? Is it a BASIC program that can be LISTed?

I have other questions about your configuration. Are you using PETVet to run your PET? And did you change the mapping of the PETVet when you say "bypass"? Do you mean PASSTHROUGH? Normally only the I/O address space is mapped as PASSTHROUGH.
Thanks,
Dave
 
Hi Dave

Thanks for reply !

I have a lot of experience with Commodore PETs but I have never heard of this program. How are you loading the program? Is it one a diskette or tape? Is it a BASIC program that can be LISTed?

The program i use is actually stored on my petdisk.
I found it on zimmerman's :
http://www.zimmers.net/anonftp/pub/cbm/pet/utilities/index.html
diagslevak.d64.GZ

The program is called: PET<--CBM RAM TEST.PRG

by list it returns 10 sys1236 so i think there is no interferance whith basic code loaded into ram.

I have other questions about your configuration. Are you using PETVet to run your PET? And did you change the mapping of the PETVet when you say "bypass"? Do you mean PASSTHROUGH? Normally only the I/O address space is mapped as PASSTHROUGH.

No i do no longer need the petvet to run the computer at this point after replacing the faulty RAM chips the pet runs on it's own.
The memorydump problem occurse when i used the petvet so to be sure there is no problem comming from the petvet it self i started RAM tests without the petvet.
Bypass or PASSTHROUGH ? all i can tell is the return i got from the petvet it self ! (see printscreen below)
I am still waiting for news about that from bitfixer !

petvet-to-pc-bypass-screen-memory.jpg

I hope this helps to clarify the issue :

Kind regards
 
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