How Do I Transplant These ROM Chips?

[Deemar]

I'd like to play these Malagai and Gauntlet chips I just got, what's the easiest way to play them? I was told I could use old Pac-Man boards but how do I remove the old chips? Is there a tool I can use? I'd prefer to use a new board if possible but I'll use an old donor if I have to. Is there somewhere I can buy a new board / cartridge to use? Please help me make this work, thanks a lot. I'd like to end up with a cool looking cartridge that can't be confused for an original.

[alex_79]

9 hours ago, Deemar said:

I was told I could use old Pac-Man boards but how do I remove the old chips? Is there a tool I can use?

You need to desolder the old chip and solder the new one in its place (or solder a socket where you can insert the new chip)

 

9 hours ago, Deemar said:

I'd prefer to use a new board if possible ...

New boards are designed for eproms that have a different pinout compared to the original Atari mask roms. So they'd need to be modified to be used for your chips.

[bluejay]

You could also use a cartridge with a ZIF socket... although I think those were designed to be used with EPROMs as well. Maybe you can find one on ebay.

There's a tool called a soldering iron and solder wick. If you're willing to spend a bit of money a desoldering drill as well. It's a stick of metal that gets hot if you plug it in, so you can melt the solder that's holding the Pac Man ROM in place, then attach your new ROMs in its place. 

You could scrape the labels off and label them with a permanent marker and masking tape.

Edited November 15, 2020 by bluejay

[root42]

8bitclassics seems to have 2K/4K PCBs in stock:

 

https://www.8bitclassics.com/product/atari-2600-2k4k-pc-board

[Shawn]

13 hours ago, root42 said:

8bitclassics seems to have 2K/4K PCBs in stock:

 

https://www.8bitclassics.com/product/atari-2600-2k4k-pc-board

 

Those are for eproms not production roms

On 11/15/2020 at 4:54 AM, bluejay said:

You could also use a cartridge with a ZIF socket... although I think those were designed to be used with EPROMs as well.

 

No. Common sockets of any flavor are just an extension of the current pinout of what is already present. Has nothing to do with chip type and pinout. Using a socket would be best for use with these. You have that part right. Soldering them into a pcb wouldn't be a good idea as far as "value" goes which seems to be important to the OP. That is unless you had the board type to use that answer used back in the day. That is info that is known but also not shared like wild cause there is too big of a chance the someone all of a sudden has an unlabeled answer game that has been cobbled together. Kinda like how the "protos" he has where put together that came from Best Electronics. 

[bluejay]

6 minutes ago, Shawn said:

No. Common sockets of any flavor are just an extension of the current pinout of what is already present. Has nothing to do with chip type and pinout. Using a socket would be best for use with these. You have that part right. Soldering them into a pcb wouldn't be a good idea as far as "value" goes which seems to be important to the OP. That is unless you had the board type to use that answer used back in the day. That is info that is known but also not shared like wild cause there is too big of a chance the someone all of a sudden has an unlabeled answer game that has been cobbled together. Kinda like how the "protos" he has where put together that came from Best Electronics. 

In that case, @Deemar I highly recommend you get a cartridge with a ZIF socket(or install your own, or whatever)

[Deemar]

2 hours ago, bluejay said:

In that case, @Deemar I highly recommend you get a cartridge with a ZIF socket(or install your own, or whatever)

Cool, do I just get one from Amazon, solder it to a Pac-Man board and then push the ROM chip into it? Is there somewhere I can order a board with one attached already? Will a cartridge still fit over this?

 

[bluejay]

3 minutes ago, Deemar said:

Cool, do I just get one from Amazon, solder it to a Pac-Man board and then push the ROM chip into it? Is there somewhere I can order a board with one attached already? Will a cartridge still fit over this?

 

There exists cartridges with ZIFs already on them but they're expensive, like $100. By that point you might as well just buy a harmony cart. You could insert the bare PCB into the atari using a flathead screwdriver, or dremel a hole through the pacman cart case.

[root42]

On 11/17/2020 at 11:28 PM, Shawn said:

 

Those are for eproms not production roms

From what I know 2732 EPROMs and the Atari Mask ROMs are pinout compatible. See attached diagrams.

 

Just looking at the diagrams again: A11 seems to be different. So I guess you were right, there is a small difference. But it should be easy to modify an existing PCB design to support the mask ROMs. If it's only one address pin that's routed differently...

Edited November 19, 2020 by root42

[root42]

Alternative: OSH Park. Here is a project which gives you the bare PCB:

 

https://oshpark.com/shared_projects/ke2psYkp

 

You can either order from OSH Park or any other PCB vendor of your choice.

[+5-11under]

25 minutes ago, root42 said:

Alternative: OSH Park. Here is a project which gives you the bare PCB:

 

https://oshpark.com/shared_projects/ke2psYkp

 

You can either order from OSH Park or any other PCB vendor of your choice.

As you can see, there's an inverter that is required when using EPROMs (for most masked ROMs, that's inside the chip).

See your diagram above. Pin 20 on one has a bar (or a slash in this case), indicating the logic is inverted.

[Wizzard]

Is there any way how to use 512 k ROM chip as a cartridge? I have an Atari 2600 clone with this chip and I know there was some cartridges with 128 games.

 

Or is there any clean 512 K cartridge, that I can burn my own dump with games?

Edited January 19, 2021 by Wizzard