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View Full Version : SuperPET 9000 doesn't quite work need help



wilykat
June 20th, 2014, 08:41 PM
I just got a SuperPET as I wanted one since I used to play with one in elementary school before they dumped it and replaced them with Apple IIs. Anyway I had some tapes and a tape player for my C64 that has PET programs. So when a nice used and semi-working PET popped on Craigslist yesterday, I jumped on it very fast and left skid mark from my driveway all the way to pick it up. $25 PET just doesn't happen :cool:

http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0465_zps5e3993aa.jpg

Anyway I had a chance to check around. I did the obvious, reseated chips ad cables as a few had gotten a bit loose. When I powered it up, I got an image which shows the power supply and monitor part is probably fine. However I can't get keyboard to work right, about half of it doesn't work.

First up, it has a one daughter board upgrade that was available later, not the original 2 daughter boards version. So there's less cables to deal with, which is a plus I guess. Looking at Google image, the older 2 daughterboard has a few more cables and a lot more chances of problem to chip creep.

http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0466_zps7bc51a1b.jpg
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0467_zps9def9793.jpg look at those gold topped RAM chips
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0468_zps6b9fed77.jpg closeup of the 2 CPUs.

I tried Googling for schematic http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/SuperPET/index.html but there's no info on the keyboard matrix. I haven't checked the cable for broken wire yet (one of many things including verifying power supply are within spec, etc) These keys do not work:
left arrow, 1, 2, 3, 5, 6, 0. and cursor left/right
tab, q, w, r, [, /, and cursor up/down
a, d, j, l, +, @, and ]
left-shift, space, andd shift lock key all do not work. Also in the number pad, only 7 works.

When I boot and the switch is set to program or 6809 I get screen with a list of programming options including cobol, fortran, and basic (any way to update these to vbasic, c++, etc :D ) I can't get anything there because the keyboard wasn't working right. Since I don't have the disk drive or the disks, I doubt I can do anything more in this mode.
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0472_zps1afd1784.jpg the waterloo screen, sorry for blurry picture I hate my cheap camera

When I set the switch to 6502 I get commodore basic 4.0 screen and nothing else. I expected the memory status and ready prompt like older PETs I am used to. Does that mean something's not working right?
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0471_zps73d77a96.jpg

The other switch, depending on the setting I can either get disk read error (since there's no drive) or nothing happens at waterloo menu. There's no change in the 6502 screen.

I could try removing the 6502 CPU and putting it in the original mainboard socket to disable waterloo daughter board and see what happens. It should be like 8032 right?

To do:

check keyboard and cable
verify power supply
check monitor area for bad caps
try to get 6502 mode working if it's not working
thoroughly dust the inside!


PS just because, I checked eBay. There is no current or recent listing for SuperPET other than a couple books. Guess it's fairly rare then?

wilykat
June 20th, 2014, 08:48 PM
Forgot to add the first time I booted in 6502, I got a monitor screen instead. It happened only once.

wilykat
June 20th, 2014, 10:25 PM
Another update, I found the schematic hiding with the older PETs, it seems to be about the same across most of PET line. The working and non working keys didn't conform to common column or row, which would rule out bad cable.

I used my multimeter and probed the contact. The keys that are working is less than 1 ohm while the keys that are not working is reading around 25k ohms. Dirty or worn contact maybe?

Pet Rescue
June 21st, 2014, 12:53 AM
Hi wilykat regarding the keyboard the first thing I would do would be to strip it down and clean the keyboard with isopropyl alcohol and an eraser on the gold contact pads even if they look clean as I had a 4032 that I had no keys working that I thought must have a chip gone down.

http://www.vintage-computer.com/vcforum/showthread.php?25525-Commodore-4032-Keyboard-Fault&highlight=

I replaced the chip but it was the dirty keyboard so don't look for the complicated most times it's something simple!

daver2
June 21st, 2014, 01:00 AM
Hi,

Nice find - I have been after one of those beasts for years! Yep, fairly rare...

The fact that you get the languages list up in the 6809 mode is good news as it indicates that most of the stuff is working - so fault finding should be a bit easier than if you were faced with a blank screen! The 6809 stuff worked from a disk only - so that is about as far as you will get with the 6809. The disk images are on the web for the SuperPET. Have a look for a chip with a 6702 label on it. This is the 'hardware dongle' chip and without it you won't be doing anything with the 6809 using the standard disks! I have removed the protection from the Waterloo disks (so that you can use the SuperPET without the 6702 chip). The images are also on the web (I can provide you with a link if you can't find them yourself).

The SuperPET is a basic 8032 with the add-on boards. You need the Zimmers SuperPET schematics AND the 8032 schematics for the 6502 board + the keyboard (i.e. the key matrix is a bog standard 8032).

My guess (and it is a guess) is that you should be able to remove the 6809 add-on board and put the 6502 in the vacated CPU socket and you should have a fully functional 8032 (i.e. divide and conquer) - although it does sound as though your initial issues were/are keyboard related.

Dave

PS: You can add to the Waterloo languages menu - you can do anything you like by hacking the boot prom (after all, it is only 6809 code)!

daver2
June 21st, 2014, 03:08 AM
I checked the 8032 schematics and the fact that there are quite a number of keys that don't work make me suspect that it is not as simple as a duff cable core or switch. I was googling recent posts for SuperPET and I came across a few on other sites that (I assume) you have also posted with slightly different information.

If the switch matrix checks out with a multimeter I would not brother too much cleaning it at this point in time as I suspect the problem is elsewhere. I would personally check the power supply lines first for out-of-specification voltages and high ripple etc. as a problem here will manifest itself in all places! Next, I would check UC11 (74LS145) - this is a BCD to DECIMAL decoder IC (although if this was faulty it should appear as a number of rows (or columns) were faulty) and UB12 (6520 PIA) - this is the interface between the 6502 CPU and the keyboard itself. I suspect this may be where the fault lies. Interestingly, the DIAG pin (J9 pin 20) feeds into PA7 of this chip. This line (when grounded) will cause the PET to enter the machine language monitor (which you also described happened once). Your problems may be associated with a partially faulty 6520 keyboard PIA.

Note that the IC references UC11 and UB12 were obtained from a schematic of the 8032 - verify yourself what the correct IC references are for your particular revision of the 6502 CPU board.

Dave

daver2
June 21st, 2014, 03:21 AM
Incidentally, the link to the 'dongle removed' Waterloo language disks is http://mikenaberezny.com/hardware/superpet/waterloo-languages/ and the later versions of VICE (Versatile Commodore Emulator) (2012 onwards if I remember correctly) includes support for the 6502/6809 SuperPET - so you can initially run the software on your PC until you get your physical hardware up and running...

Dave

wilykat
June 21st, 2014, 12:02 PM
Looks like on late version of waterloo that chip is soldered in. Make sense since you'd need the whole board and second CPU to use the program anyway. The program wouldn't work without that 6809 CPU.
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0476_zps5373109e.jpg
It's near the front, just to the left of 64k banks and behind the first row of chips. Perma-soldered in.

Guess I can use any version, cracked or not. I still need disk drives, the ones I have are serial and can't be used on PET without IEC to IEEE-488 adapter, which I believe is as rare as SuperPET itself or an IEEE-488 disk drive. I am getting SD2IEC soon for my 128 I'll be able to transfer disk images. All I need is a suitable disk drive, preferable one with both IEEE-488 and IEC so I don't need to worry about making the disk readable from 1571 drive to whatever PET drive I get.

I need to get new tip for my soldering iron so I can desolder the shift lock key to take the board off the keyboard. I did some probing with ohm meter, the keys that are working are under 1 ohm but the keys that aren't working are about 25k ohms. Then I'll move the 6502 CPU down to the mainboard and see what happens.

Pet Rescue
June 22nd, 2014, 06:11 AM
Looks like on late version of waterloo that chip is soldered in. Make sense since you'd need the whole board and second CPU to use the program anyway. The program wouldn't work without that 6809 CPU.
http://i126.photobucket.com/albums/p101/uzumaki_arashi_album/SAM_0476_zps5373109e.jpg
It's near the front, just to the left of 64k banks and behind the first row of chips. Perma-soldered in.

Guess I can use any version, cracked or not. I still need disk drives, the ones I have are serial and can't be used on PET without IEC to IEEE-488 adapter, which I believe is as rare as SuperPET itself or an IEEE-488 disk drive. I am getting SD2IEC soon for my 128 I'll be able to transfer disk images. All I need is a suitable disk drive, preferable one with both IEEE-488 and IEC so I don't need to worry about making the disk readable from 1571 drive to whatever PET drive I get.

I need to get new tip for my soldering iron so I can desolder the shift lock key to take the board off the keyboard. I did some probing with ohm meter, the keys that are working are under 1 ohm but the keys that aren't working are about 25k ohms. Then I'll move the 6502 CPU down to the mainboard and see what happens.

I find that a hot air surface mount desolder station to be excellent for removing chips, but practice your technique on a scrap board first to save damaging your board.

25k ohm is indicative of dirty contacts as they should be virtually a short as with the functioning keys.
Get the isopropyl and eraser out first before you do anything!
But that's only my advice!

wilykat
June 22nd, 2014, 03:17 PM
Cleaned, the keyboard seems to be fully working while in 6809 mode. I still can't get 6502 mode at all and I even removed the entire board and moved 6502 CPU to the lower socket, I still see only a basic line and no memory or ready line. Seems like something is getting stuck on 6502 initialization? I'll use the 8032 schematic and check the voltage. I saw something about VDRIVE signal on PIA or VIA.

I forgot about the sound, since I couldn't hear but my Mother heard it and told me it sounded like 3 short beeps when I first power it on.

wilykat
June 24th, 2014, 03:47 PM
power from transformer:
4-5 reads 8.7v AC
5-6 reads 8.7v AC
4-6 reads 17.5v AC
7-8 reads 16.3v AC

(this is without the 6809 board installed ie default 8032 model)

I did get monitor a few times today and when I checked VDRIVE I never got higher than 3.5v DC. As mentioned here www.6502.org/users/andre/petindex/repairs.html it could be that one chip. It is not socketed in my PET though. so it'd be some work to remove it.

I don't have another PET or even some of the chips, any idea what I can do?

wilykat
July 8th, 2014, 01:29 PM
No response for over a week? I guess no one has any idea? Maybe I'll mothball this PET until I can get a cheap 8032 or 9000 for spare parts.

daver2
July 9th, 2014, 06:20 AM
Sorry wilykat - for some reason I missed your last couple of posts.

You say that the keyboard seems to work OK in 6809 mode - is this correct?

If so - how do you know? Does the display work OK in 6809 mode?

If so - there is nothing faulty with the video hardware of the SuperPET (as it is the same hardware that is used for the video display for both the 6809 and the 6502).

If the video display works OK in 6809 mode (as does the keyboard) I would be looking around the 6502 itself and/or the 6502 ROMS and/or the 6502 ROM decoding.

Dave

dave_m
July 9th, 2014, 09:24 AM
I still see only a basic line and no memory or ready line. Seems like something is getting stuck on 6502 initialization?

I agree with daver2, I took a look at the power-up init routine and I'm guessing that something is wrong with the $C000 ROM (UD9) as that's where the routine ($CF83) that converts the last good RAM address into a decimal number and posts on the screen. Check the /SEL C Chip Enable for pulses if you have a logic probe. Check the solder joints at UD9, etc.
-Dave

dave_m
July 9th, 2014, 09:33 AM
power from transformer:
4-5 reads 8.7v AC
5-6 reads 8.7v AC
4-6 reads 17.5v AC
7-8 reads 16.3v AC



All the numbers are about 15% low including the Vertical Drive which should read a DC average of at least 4.5V, yet things seem to be working fairly well. I suspect your voltmeter is a little off. Can you calibrate it with a known good source like a battery and change the voltmeter batteries if needed.