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Bruce Tomlin

The 7800 cartridge board thread

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Yes, I had done something very similar with Beef Drop and Frogger, except that I had a 7404. Those carts work *wonderful* with that setup of those two games.

 

I wish I would have known you were going to do it that way; I would have either sent you the boards or done it for you to save you the trouble.

 

Bob

Actually I wanted to see how time consuming it would be. Wasn't as bad as I thought it would be. The new eprom is socketed so I can use it for future test games. I also finally got around to installing the 8bitdomain video mod into the 7800 I bought from someone on here second hand a long time ago since I had to get the soldering stuff out anyways. It took a little long, since the I had to move wires around in the video plug since it the video jack was not wired correctly. Currently I am only using composite, so I just installed the one jack with the four wires and use it for audio and video since I had to move things around in the connector anyways. Can always add Svideo later. Works good though. Pokey sound, sounds a little quiet in Beef Drop though, not sure if that is the ball blazer board or the video mod.

 

Ken

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Works good though. Pokey sound, sounds a little quiet in Beef Drop though, not sure if that is the ball blazer board or the video mod.

 

It's a known issue with the video mod, I think I posted the fix in one of the threads about the video mod a while ago.

 

Mitch

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Works good though. Pokey sound, sounds a little quiet in Beef Drop though, not sure if that is the ball blazer board or the video mod.

 

It's a known issue with the video mod, I think I posted the fix in one of the threads about the video mod a while ago.

 

Mitch

Yes, had read a lot of those posts before installing it and wasn't expecting it to go smooth.

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I have Q*bert running on a Pole Position 2 cart board.

 

I mounted an inverter on the rear with the Vcc connected to one of resistor pads at the top, ground to a scraped place in the ground area in the middle of the board. Then connect the input of the inverter to the OE' pad of the eprom (which is fed with A15), and the inverter output to the OE' ic leg bent out. I also clipped all unused pins flush with the chip.

 

Well actually the one I built is a lot uglier since I used a socket for the eprom so I can use it for testing, I then had to cut and tap into a15 (which sucks since it doesn't have a via or anything nice to solder to. I am attaching a picture but it is ugly in both quality and construction but gives an idea of where I would mount the inverter (well actually a NAND since that is what I have) in case anyone has any better ideas. I guess a transistor and couple of resistors might work but would probably actually be more work. I could probably also leave and attach one of the other inputs to some other ground points for more stability (or use hot glue or epoxy?).

 

I also think I should be able to use a 7402 (NOR) chip and get 48K on 27512 (the low 16K would not be used). I would just NOR A14 and A15 together to feed to OE' and A15 would also need to then be connected to the A15 pin of the eprom.

 

Once I get some supplies I think I will time how long it takes to build one completely. I definately need to get some thin wire with heat resistant insulation.

post-4263-1150906664_thumb.jpg

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Hey Ken:

 

Just a question - how come you didn't want to use a 'Hat Trick' board instead of the PP2 board? All that's involved there is desoldering the chip and soldering in the eprom. - up to 32K :)

 

Bob

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Hey Ken:

 

Just a question - how come you didn't want to use a 'Hat Trick' board instead of the PP2 board? All that's involved there is desoldering the chip and soldering in the eprom. - up to 32K :)

 

Bob

Got a cheap source for a lot of Hat Trick boards? :-)

I am looking to find a way to mass produce (well mass is probably 20-50) cartridges as cheap as possible in parts since I want to make something for the extra labor. I will probably try to use mostly whatever I can find (but the most common, or crapiest games).

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Got a cheap source for a lot of Hat Trick boards? :-)

 

Why yes I do :D

Carts and Cases (72)

 

This works out to about $3 per cart (including shipping), for the boards and case that's pretty good :) (what's more, I've noticed that the labels that are on these carts for some reason are pretty easy to get off... to me that's worth a lot right there)

 

They also have smaller quantities, but I was leaning toward your high end of the range.

 

I've been thinking about going to them again because I might do another run of 7800 PacMan games soon :)

 

Bob

Edited by PacManPlus

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This works out to about $3 per cart (including shipping), for the boards and case that's pretty good :) (what's more, I've noticed that the labels that are on these carts for some reason are pretty easy to get off... to me that's worth a lot right there)

 

I've been thinking about going to them again because I might do another run of 7800 PacMan games soon :)

 

Bob

 

Best deal I have got so far is 12 pole pos 2 carts 50 cents each and 3.49 to ship 12. So less than $1 a piece.

I'll keep a look out for hat tricks since they convert easily.

I have also been trying to snag cheap BallBlazer carts when I see them and have reasonable shipping.

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[

Best deal I have got so far is 12 pole pos 2 carts 50 cents each and 3.49 to ship 12. So less than $1 a piece.

I'll keep a look out for hat tricks since they convert easily.

I have also been trying to snag cheap BallBlazer carts when I see them and have reasonable shipping.

 

You can get Ballblazer from the same source Bob pointed out. They run about $3 bucks each NIB, I think that is about the best you can get for a pokey enabled PCB. They are really great people to deal with also. I have been buying my 7800 boards from them for 2 years now.

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Ok... That's definately a better deal - just trying to help :)

Yea but 12 probably wont go very far. Thanks for the link.

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Ok... That's definately a better deal - just trying to help :)

I hope they are all the same verison of the board that my pole pos 2 is. I know there are multiple versions of some of the boards. My mspacman is layed out a lot differently.

 

Are there any other boards that put the rom on the same side of the board as ballblazer. I like ball blazer because I can use a socket (can be useful for development or early releases) and have it fit into the cartridge shell. Is hat trick similiar to ballblazer in that respect?

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Are there any other boards that put the rom on the same side of the board as ballblazer. I like ball blazer because I can use a socket (can be useful for development or early releases) and have it fit into the cartridge shell. Is hat trick similiar to ballblazer in that respect?

 

yep

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I hope they are all the same verison of the board that my pole pos 2 is. I know there are multiple versions of some of the boards. My mspacman is layed out a lot differently.

 

Are there any other boards that put the rom on the same side of the board as ballblazer. I like ball blazer because I can use a socket (can be useful for development or early releases) and have it fit into the cartridge shell. Is hat trick similiar to ballblazer in that respect?

 

You may want to check out Dan Boris' web site, on this page (scroll to the bottom) you can see just about every 7800 cart board made.

It doesn't tell you every game that used a particular board but there are a few of us that have opened a pretty good amount of 7800 games and can probably tell you what you'll find in a particular game.

Incidentally, I have seen two different boards in PP2, the very common CO24926 board and the rather uncommon CO25474 board.

 

Mitch

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You may want to check out Dan Boris' web site, on this page (scroll to the bottom) you can see just about every 7800 cart board made.

It doesn't tell you every game that used a particular board but there are a few of us that have opened a pretty good amount of 7800 games and can probably tell you what you'll find in a particular game.

Incidentally, I have seen two different boards in PP2, the very common CO24926 board and the rather uncommon CO25474 board.

 

Mitch

Yep I have looked at that page quite a bit. Is Rev A usually the first release of a board or the first change? The ballblazer board I first modified and posted a picture of is a little different then one I looked at last night (which is rev A and matches the one on that web site). It is routed pretty close to the same in layout but has traces from the 7404 and some from the pokey chip that go off the board in areas that have been snapped off (it doest have the nice clean edges). You can see smoe of that in the picture. It has the same part number C026461 but no revision.

 

That page also is missing some. My ms pacman is C300464 reva and has the rom mounted higher up on the board and a bunch of wire jumpers. Not quite sure what the jumpers are for (they dont necessarily have to jumper over anything). There are 8 and they are probably on the data lines. It also has no capacitor, although maybe the board is designed to kind of act a little like having one. There is also one wire added between two of the pins under the eprom (from ground pin to another pin).

Edited by kenfused

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Yep I have looked at that page quite a bit. Is Rev A usually the first release of a board or the first change? The ballblazer board I first modified and posted a picture of is a little different then one I looked at last night (which is rev A and matches the one on that web site). It is routed pretty close to the same in layout but has traces from the 7404 and some from the pokey chip that go off the board in areas that have been snapped off (it doest have the nice clean edges). You can see smoe of that in the picture. It has the same part number C026461 but no revision.

 

That page also is missing some. My ms pacman is C300464 reva and has the rom mounted higher up on the board and a bunch of wire jumpers. Not quite sure what the jumpers are for (they dont necessarily have to jumper over anything). There are 8 and they are probably on the data lines. It also has no capacitor, although maybe the board is designed to kind of act a little like having one. There is also one wire added between two of the pins under the eprom (from ground pin to another pin).

 

Rev A boards are usually the first release from what I've seen, though some of them don't list a rev version at all.

It sounds like your Ballblazer board is a different pressing but the same rev.

 

Wow, you found a C300464 board, those are pretty uncommon! I think I've only found one and you're right, Dan doesn't have that one listed. I haven't figured out what that extra section with the jumpers on all of the data lines is for either. I was thinking it might be some kind of hardware add-on but I couldn't think of any real use.

 

Mitch

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Do all hat tricks use the C100339 board?

Are any other ICs ever populated but U1 and U2 on hat trick.

 

 

Yes all use a 339

No, no extra population on random boards they are all populated the same.

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Wow, you found a C300464 board, those are pretty uncommon! I think I've only found one and you're right, Dan doesn't have that one listed. I haven't figured out what that extra section with the jumpers on all of the data lines is for either. I was thinking it might be some kind of hardware add-on but I couldn't think of any real use.

 

Mitch

 

 

I found one yesterday and they work the same as the others as far as functionality goes but the jumpers and the resistor are a mystery to me also. I found it inside of a choplifter.

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Do all hat tricks use the C100339 board?

Are any other ICs ever populated but U1 and U2 on hat trick.

 

The PAL version of Hat Trick usually uses a different board but I think all of the NTSC ones were the same.

 

Mitch

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Do all hat tricks use the C100339 board?

Are any other ICs ever populated but U1 and U2 on hat trick.

 

The PAL version of Hat Trick usually uses a different board but I think all of the NTSC ones were the same.

 

Mitch

Well I was trying to find a way to not have to remove the existing rom, and then just populate U4 with an eprom.

So far I havent got it working but I keep finding mistakes I made so may try a fresh start later.

Besides modifying a couple jumpers it does require adding 3 wires and getting a pin of U2 pulled out so even if I get it working I think it will be more work than removing an IC.

 

So far I have:

 

clear 28 holes for U4 and 2 holes for R1

Removing any solder from W2, W6, and W7 if any have blobs.

Heat and pull out or somehow get pin 6 severed to U2 (unfornately the trace is under the IC). Enough needs to be left to solder to though.

Add solder to W3 and W4 if they do not already have it.

Install jumper wire from pin 11 of U2 to pin 8 of U3 (Get A14 to the EPROM)

Install jumper for R1 (maybe 3.3K resistor is better?) (Get CE' of ROM high)

Cut trace to U4 pin 1 (48K only).

Solder jumper wire from pin 6 of U2 (that was pulled out ) to pin 2 or 3 of U2 (skip the inverting of A14)

Solder jumper from U4 pin 1 to u3 pin 3 (48K only) (Get A15 to eprom)

Add cap C4 if you are feeling generous.

 

Note U3 and U5 are still left unpopulated

 

Anyways, probably stuff wrong since I keep making stupid mistakes.

The whole point is to get the onboard rom disabled, get A14 and A15 to the EPROM, and the NOR of A14 and A15 to the CE' of the eprom.

48K would only be using the upper 48K for a 27512

Back to the cart schematics tomorrow since I have a headache now.

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Have you considered using a solder pot to pull the chips? It's like the poor man's wave solder device. It's a little electric hot pot in which you place a brick of solder. Basically you dip the board in and it heats all the pins and you can just pull the parts out.

 

Never tried it myself, but have heard it works quite well. I think jameco.com sells them.

 

Chad

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IT takes max like 5 mins to desoilder a 28 pin chip properly off a board, I would think it would be easier to go that route than to find a way around removing the chip. Even a cheapo 10 dollar soilder sucker from Rat Shack will do, hell thats all I got.

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Have you considered using a solder pot to pull the chips? It's like the poor man's wave solder device. It's a little electric hot pot in which you place a brick of solder. Basically you dip the board in and it heats all the pins and you can just pull the parts out.

 

Never tried it myself, but have heard it works quite well. I think jameco.com sells them.

 

Chad

 

Heh, that doesn't work nearly as well as a Hakko 808, good suggestion for a low budget though. ;)

 

Whatever happened to someone manufacturing 7800 boards? Maybe I sould take that one on too. :ponder:

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Heh, that doesn't work nearly as well as a Hakko 808, good suggestion for a low budget though. ;)

 

Whatever happened to someone manufacturing 7800 boards? Maybe I sould take that one on too. :ponder:

 

I told you that months ago. :P CPU = RESULTS :thumbsup:

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