help needed with my Williams Robotron ROM errors!

JohnMc123

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I've been working on my Robotron for a while now. When I got this game it had some bigger fuses in the power supply board and one was wrapped with tinfoil. The game was dead when plugged in.

I have since replaced:
>a new 110 volt power cord and plug from the wall outlet to the machine;
>all electricity capacitors;
>all header pins with Molex pins;
>all .156 Molex KK Series Connector Housing and Molex .156 Trifurcon Pins Female 18-20 AWG;
> Williams D-8784 Mega Deluxe Power Supply Rebuild Kit;
>10K OHM Williams +5vdc Power Supply TRIMMER POTENTIOMETER (P1037);
>Williams 4164 RAM adapter;
>new 4164 RAM; and
>new dual wipe IC sockets for the new 4164. After desoldering 400 joints with a Soldapullt and wick, I snaped and bouught a Hakko FR300!

and also have but, haven't installed because, I was going to try and get the game up and running first:
>Wells Gardner K4900 Series Cap Kit;
>560uF 200V Nichicon 105c B+ Filter capacitor
>MSH1FAP08 K4900 / K5501 Flyback
>2SD871
>STR380

I haven't ordered any new ribbon cable yet. I thought I might get away without it.

>So far I've got the original linear power supply up and running and have dialed in at +5.00 volts, or above to the RAM chip and the ROM are getting around +5.08 volts.
>When I first powered the game up I had a, "1-1-1" error and the video can be seen here: https://youtu.be/AbfuZPFYaxA and a ROM error 7 on the screen.

>I cleared the RAM error and still had the ROM 7 on the screen and and flashing, "2-3-1"; "2-0-1" and a rug pattern, then after a while the 8 segment LED would display, "0" and the screen would start cycling the game screens one screen and the video is here: https://youtu.be/MGWyUoSnoP8

>I took the board back to the bench and cleaned off the window of the ROM 7 and erased the chip and then downloaded the new EPROM and reburnt the EPROM and checked it to make sure and I was successful. I put the ROM 7 back in the board and then back into the game and now have a, "2-0-1" and just a rug pattern, that keeps resetting.

John
 
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there should be no such thing as a 2-3-1, as there is no rom 31. sounds to me like the PIA (6821) is bad on the rom board if you're getting random rom errors. I don't think I've ever seen one bad on a rom board before though, so I don't know the exact symptom from my own experience.

the adjustment pot mod on the power supply is additionally worthless, I don't know why people keep pushing for it. you should have no issues running this hardware at all between 4.9-5.00V.
 
There's multiple DIFFERENT rom sets for Robotron, it looks like your rom7 you reprogrammed might be from a different set. You might try re burning ALL to make sure they are all from the same set. OR alternatively you can just test ALL of them (read and verify) to make sure they match the files of the set you got the rom 7 from.
 
getting closer!

Mecha, and toledoflyer thanks for the feedback.

toledoflyer, I checked the ROM 7 I burnt and you were right, I it was the blue version I burnt and my machine has the orange ROMS, I have no idea why I was confused. After reading from http://www.robotron2084guidebook.com/technical/rom/
"They were never released with orange labels. The labels were yellow but somebody ran a red marker across them and over time it faded to orange. The B was penciled on because they didn't want to wait for another run of the stickers from the printer, plus they had stacks of the A labels"

Mecha, I turned my game on and was greeted by the rug pattern and those crazy errors I shot a video here: https://youtu.be/pKymg3ossWs

I got backwards 3 and what at first glance looked like a 1 was a L! I'm running out of time this evening so, I'll continue this tomorrow; however, I ran my finger/hand over the chips around the RAM and the decoders were warm and the chips closer to the RAM were a lot warmer. I've included a picture of the warm, and warmer spots. The rest of the chips were cool to the touch. This is only after a few minutes too.

I'll have a better look tomorrow.

John
 

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your 07 rom is probably wrong, as toledoflyer stated. your rom set is from the yellow-orange roms (https://www.emuparadise.me/M.A.M.E....s/Robotron:_2084_(Yellow--Orange_label)/98434) and you probably sourced your code from the solid blue label roms.

your 1-3-9 error is pretty suspect, as the ram banks stop at 8. the 1-2-1 however, you can trade it with either the 1-1-1 or 1-3-1 rams to see if the problem carries, stays, or magically fixes itself.

I think you may have something very complicated here. if you want, I fix these, and I can take on new stuff again. PM me or ignore me.

good luck
 
update:

My CPU board has a date of September 1982. Is this the date I should use when choosing which document to read? I've found 4 different documents and I'm thinking I should go with the 2 newest because, the date on my CPU board says September 1982, or is there a different date somewhere else on the game I should be referencing?

>newer - Robotron_Drawing_Set_(16P-3005-103)_March_1982
>older - Robotron_Drawing_Set_(16-P-3005-103)_April_1982.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>newer - Robotron_Instruction_Manual_(16P-3005-101)_Mar_82
>older - Robotron_Instruction_Manual_(16P-3005-101)_May_82

In order to try and move forward I'll start from the beginning, I bought this game with blown fuses and one was wrapped with tinfoil (see attached picture). I rebuilt the linear power supply and got that up and running. My plan was to change the tri voltage RAM with the new single voltage 4164 RAM and try and power it up. When I saw that the original RAM was mostly burnt looking I (see attached picture) I decided to also replace the IC sockets as well. Here's where I ran into trouble. When I removed the IC sockets I lifted/removed maybe 5 pads on the first couple sockets. All the pads that I removed had traces on the parts side of the board and not the solder side.

This isn't the worst of it. When I went to solder the new IC sockets I ran out of the normal 6mm (0.23622") diameter solder that I use so. When I went to the store all they had was 22 gauge (0.032") which doesn't seem like a lot bigger; however, it sure felt like it to me! As a result I ended up putting way more solder in the joints and also way more heat. I even managed to move some of the solder up into the sockets where the IC legs go! Now some chips don't sit right, and who knows what other complication I've introduced.

I'm going to try and bring everything back to original design intent and get a fresh start on it. I've removed half of the 24 IC sockets again; however, because, so much heat was used, I'm lifting some more pads again. They are still only the ones that have traces on the parts side and not connected to any traces on the solder side. I guess those ones have less material to soak the heat and are more likely to lifting.

The chips that I mentioned in a previous post that are warm also look like they have burnt legs (see attached picture). Diode 9 and 10 also look burnt and fail on the diode test mode on my multimeter (see attached picture) I'm going to finish putting new IC sockets back in and jumper the legs that have lifted pads. I got new solder that's 0.025" diameter and I love it.

I also noticed that the capacitors on the capacitors on both side of the banks of RAM are failing. They are supposed to be 1 microfarad (MDF) at 50 volts. I would like to order some replacements and I don't recognize what type of capacitors they are. Would anyone know so, I could order some new ones. Would they be tantalum? I've included them in the picture highlighted in red.


John
 

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Those are .1uf ceramic caps. They dont make them in the glass diode style case anymore so the replacements won't look like those. Also, it's very unlikely they are bad unless they are physically broken. Since they are just bypass caps the board will work fine even with several of them removed.
 
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