Playchoice 10 rom help

GrndMstr

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Hello all. I am restoring a Plachoice 10. I have a few boards that have bad mask rom chips. Either the graphics are corrupt (bad U1) or the titles display until selected. The system then refreshes and that game is gone (bad U2). My question is: can I replace a mask rom with an eprom chip? I see lots of people that can burn games onto eproms but no one says anything about mask roms. I am not looking to swap the games out with different games. I just want a functional copy. I have taken the roms out and reset them to make sure it wasn't something simple like a loose chip. I am assuming the PCB is good because the system will display info or corrupted graphics. Interchangeable chips would make this an easy fix. The board I am looking to repair is my Super Mario Bros 3. There are others but this is my first priority. All the pictures I see lead me to believe that they are interchangeable. The PCB's look identical. Any thoughts or know how on this would be great.

Thank you in advance
 
You certainly can replace a mask rom with an eprom, you'll often have to change a couple of pins around, I'd suggest doing this on a socket so you're not making any permanent changes to the board.
 
You certainly can replace a mask rom with an eprom, you'll often have to change a couple of pins around, I'd suggest doing this on a socket so you're not making any permanent changes to the board.

If the mask roms are the same as what they used on NES carts, then I can tell you/show you how to do those no problem (I make NES repros all the time). If not... then you'll have to find the pinout for the roms and swap them around as needed.
 
I'm pretty sure you wouldn't need to rewire anything, just possible add/remove solder to certain SL points and cut/solder the CL points. I don't know the exact configuration, but I have an SMB3 cart that used EPROMs at home, I could get pictures/notes of it, if that helps.

Another option, maybe not the best for SMB3 (it's not rare but it tends to be in demand), would be to remove MaskROMs from the NES cartridge.
 
no pinout changes

the eproms are drop in replacements except for like he said the sl and cl points, from what I was told. I'm not sure how much you want to spend on fixing it but if you want to send it to me with a 20.00 bill I will fix it. otherwise if you need help let me know I can get the answers just takes a little reading and comparing pictures.
I'm pretty sure you wouldn't need to rewire anything, just possible add/remove solder to certain SL points and cut/solder the CL points. I don't know the exact configuration, but I have an SMB3 cart that used EPROMs at home, I could get pictures/notes of it, if that helps.

Another option, maybe not the best for SMB3 (it's not rare but it tends to be in demand), would be to remove MaskROMs from the NES cartridge.
 
Hello all. I am restoring a Plachoice 10. I have a few boards that have bad mask rom chips. Either the graphics are corrupt (bad U1) or the titles display until selected. The system then refreshes and that game is gone (bad U2).

What you're describing there does not sound to me like a game issue, but a PlayChoice PCB issue. In all likelyhood, the games loaded onto your PCB are fine; it's the PCB itself that you need to have looked at.

Just something to think about before you go frankensteining some perfectly good PlayChoice games...
 
it is possible

It is possible but I don't think so I think it is a bad chip. I have repaired 6 or 7 of these in the few weeks I have owned my playchoice and what he is describing is quite common. I have a whole bag of bad eproms from these games. Only one game was the eprom reusable. I have never had to deal with the mask roms myself yet but hear there is not much to using standard eproms. I have some boards with mask roms but have not came across a bad one yet, but I have only owned a playchoice maybe a month or so.
What you're describing there does not sound to me like a game issue, but a PlayChoice PCB issue. In all likelyhood, the games loaded onto your PCB are fine; it's the PCB itself that you need to have looked at.

Just something to think about before you go frankensteining some perfectly good PlayChoice games...
 
Thank you guys!!

Hi guys,

First off I want to thank you for taking the time to respond to this thread. I acquired this unit a while back and it was in terrible shape. I have slowly been putting it back to "like new" condition. The Playchoice board is in great shape. I have verified that all 10 sockets work with other working roms. I have no problem cannibalizing a NES cartridge if that is the easiest way to repair this. I am hoping to repair this with as little modification to the board as possible. I like to keep things stock if I can. Don't know why but I do. I had this same problem on a Fester's Quest board. It had 2 jumper wires and one was severed. I replaced the wire and it worked good as new. At first I thought that might be the case here but I haven't found any info supporting that. I think I would like to try the SMB3 Nes swap first. If not I will start going at it with the soldering iron. Any links you have or info on how to accomplish this would be helpful. Once again I thank you for your time and my Playchoice is the most appreciative of all. :D
 
To remove the ROMs cleanly, you really need some kind of vacuum pump to remove the solder from the holes. Actually I could re-use the other parts from an SMB3 board, so if you didn't want to desolder it yourself, I could do it for you (just include shipping cost or stamps).

I'm not sure if the Playchoice boards are really documented anywhere (otherwise, more NES info than you may ever want to know is at http://nesdev.com/), maybe later tonight I'll pull my board out and note the configuration.
 
My SMB3 board has quite a few mods on it, namely a resistor and capacitor in series that connect pins A21 and A17 to ground (which if you know 6502 hardware, is Phi2 and A12). Also 2 capacitors in parallel connect pin 26 of the SRAM (U6) to ground (that is pin CE2). I kinda see what it's doing, but not why.

I also have another SMB3 board that I was trying to fix for someone.

Boring list follows, but I figured this would be more precise than pictures:

SMB3 board with EPROMs in U1,U4,U5 - PCH1-01-ROM-G
Going left to right, top to bottom

SL26 open
CL25 closed

SL32 open
SL31 open

SL21 open
SL20 closed - SL20 is manually wired to the left pad of SL21

SL35 open
SL38 open

SL34 open

SL19 open

CL22 closed

SL36 open
SL37 open

SL24 open
CL23 closed

SL29 closed
SL30 open

SL27 closed
SL28 open

SL17 closed
SL33 open

SL3 closed
SL18 open

SL9 open
CL8 closed

SL13 closed
SL14 open

SL7 closed
SL6 open

SL1 closed
SL2 open

SL5 open
CL4 closed

SL15 open
SL16 closed

SL11 open
SL10 closed
SL12 open

diode is installed at D5
 
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