14 replies to this topic

[gnnash]

It seems that some people who are trying to add a cartridge port are running into an issue where 4K carts will not run. This is due to a bad trace leading to Pad 20, the A11 line. It turns out that Pad 20 is useless on these machines, but there is a pin on the ROM chip which can be easily soldered to instead of Pad 20.

Since my board is now covered with a sprawling mess of cartridge port wires, I have indicated the alternate Pad 20 location below on Emehr's Rev. C board cheat sheet (I hope you don't mind!) . Emehr, if you could please add this to your visual cheat sheet if you can, for Flashback 2+ modders, that would be great.

Attached Thumbnails

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[wongojack]

Awesome! - Thanks for doing this work for us

[player 0ne]

hey. would it be possible to remove the 40 games chip and install it on a black cart board? since the FB2 works without the chip, the chip should work without the board! do all the pins from the chip goto the pads for the cart port? i cant wait to play with mine. ill need some more to mess up though., off to the flea market!

[player 0ne]

Im doing the mod to mine right now. pad 20 and a11 have no continuity. so mine is prolly like this, right? if it wasnt for you pointing this out i would have never figured it. i mean, its labled, why wouldnt it work.
thank you soo much gnnash

[lbaeza]

Hi gmnash

Thank you very much for posting that Visual Cheat Sheet.
I'm in the middle of a FB2 cart port hack, so this will come in very handy.

Do you know of a popular 4K cart to test if the pin 20 is working OK?

Regards

[awace]

I see what happened this happens all the TIME with silk screen crocks when i worked at automed we would have vareinces in silk screen that only could be TOLD by human voice as a pass it along!!! they placed the circle in exact place that the pin needed was they just didnt use a jumper wire cause thats part of a MOD and they are cheap...

[wongojack]

gnnash, on Fri Jun 10, 2011 10:26 AM, said:

It seems that some people who are trying to add a cartridge port are running into an issue where 4K carts will not run. This is due to a bad trace leading to Pad 20, the A11 line. It turns out that Pad 20 is useless on these machines, but there is a pin on the ROM chip which can be easily soldered to instead of Pad 20.

@gnash - Hey did the Flashback on board games still work after you used this as a work around?

Edited by wongojack, Sat Nov 5, 2011 9:14 PM.

[iesposta]

Cart mod finished. Flashback 2+ works great!
On board games still work fine. Installed a switch on the back to choose built in games/cartridge.
Now that it's finished, I saw the mod where the cartridge insert is in the lower left front.
That is so cool! Now I wish I had done it that way.

[kenjennings]

Is FB2 or FB2+ the preferred board for the cart port modification? I have one of each and thought it was the FB2+, but after reading about the pad 20 problem I'm starting to wonder.

Edited by kenjennings, Fri Mar 30, 2012 10:28 PM.

[iesposta]

I would say the FB2+ model would be the best one for the cart modification.
Aren't there like three board versions of the FB2 - A, B & C?
Instead of soldering to pad 20, you just solder to a pin.

Tin all the pads and wires. This takes longer, but there is less chance of damage because you can solder very quickly and it won't overheat or lift traces.

I actually used old hard drive connector cable, but I didn't solder to the cartridge port pins. I just used two of the black plastic connectors. The connector cables usually have two black connectors and a gray connector. And there is enough wire to run from the circuit board to the cartridge port. One side fits right on to the cartridge pins from 1 to 12, and another one back to back for pins 13 through 24. Every other wire is connected to the pins. I guess connectors could come loose, but it works for me.

Another good tip is to temporarily secure the circuit board with the difficultly switches to the main circuit board with clips. The gray wires will break if stressed too much-- it happened to me (and WongoJack I believe.)

[tk3000]

Hello Folks,
I performed the mod, following the map the solering points/pads to a cartridge slot of an old non-functional atari2600 I had laying around. But I made a mistake of oversoldering the J3 pads and eronding them, so I tried to uncover the trace leading to such pads but I was not sure if I was accurate with the uppder pad. I would like to know if there is an alternative spot equivalent to the upper pad of J3 so that I could hook the wire there.
thanks

[iesposta]

tk3000, on Wed May 16, 2012 11:06 AM, said:

Hello Folks,
I performed the mod, following the map the solering points/pads to a cartridge slot of an old non-functional atari2600 I had laying around. But I made a mistake of oversoldering the J3 pads and eronding them, so I tried to uncover the trace leading to such pads but I was not sure if I was accurate with the uppder pad. I would like to know if there is an alternative spot equivalent to the upper pad of J3 so that I could hook the wire there.
thanks

By upper, do you mean pad closest to the joystick ports? That appears to be ground.
The one closest to the epoxy blob, appears to come FROM the epoxy blob, so you would have to scrape the trace.

[awace]

I made the MOD TO A FB AND PUT IT INTO A ATARI2600 and used the orginal cart slot and used the b.w switch for built in and carts and ch3 ch2 ch4 switch for b.w also i used the 5v+ power supply too I scratched every thing exept the on off switch off the original 2600 board and wired them into the fb even the joystick ports and all cart slot wires I had to scape black and white switch completly off traces and was a pain in the but but it works it plays most games I havent tried a 4k game although since i read this along time ago i assume i soldered the a11 line already ..
PS it does play hangly man and hackem it also plays combat rock and some of my custom hackomatic II mod games too.
I also took a apollo cart apart and stole the idea on how to make my own carts using a old pacman cart since i had lots of them I used the apollo cart to see how they hooked the 7404 and its 4 pins up to the cart now i have a prototype to cheat from and once i hook the 7404 up properly I just add a socket and a 2732 and viola a 8k rom to the 2732 and viola I have my own custom cart..

[tk3000]

iesposta, on Wed May 16, 2012 6:12 PM, said:

tk3000, on Wed May 16, 2012 11:06 AM, said:

Hello Folks,
I performed the mod, following the map the solering points/pads to a cartridge slot of an old non-functional atari2600 I had laying around. But I made a mistake of oversoldering the J3 pads and eronding them, so I tried to uncover the trace leading to such pads but I was not sure if I was accurate with the uppder pad. I would like to know if there is an alternative spot equivalent to the upper pad of J3 so that I could hook the wire there.
thanks

By upper, do you mean pad closest to the joystick ports? That appears to be ground.
The one closest to the epoxy blob, appears to come FROM the epoxy blob, so you would have to scrape the trace.

ATARIAGE FOLLOWUP WITH FLASHBACK 2 ISSUES
Sorry for not having catched the response before. The flashback2 I have has silkscreen with a table of corresponding values and has pads with numbers in the back of circuit board to as a reference for the cartridge connections, but the soldering pads/points are in different positions from the ones I saw on photos here on the forum, maybe I have different circuit board revision (hopefully mine is now a fake one). The following is a photo of mine with some indication:




By upper pad I mean the soldering point pointed by a yellow line with a number 1 (pic above)., and I tested and there are indications that it may be a ground. The 1 and 2 marked numbered yellow lines ( added editing the image) are only to help visualize are equivalent to J3 on circuit board and they the ones I messed up and eroded the plated soldering point by overheating them, but I believe that I was able to scrape some of the mask of the circuit board trace and was able to solder it there (but not I am not 100% if I got the right trace).

Another object of confusion for me is the soldering point/pad 21, it is pointed on the pic above by a yellow line and the no. 3. In my circuit board the silkscreen no. 21 is surrounded by soldering points so it is not clear to which soldering point does the no. 21 refers to.


Thanks for any help

[iesposta]

tk3000, on Sat May 26, 2012 4:59 PM, said:

iesposta, on Wed May 16, 2012 6:12 PM, said:

tk3000, on Wed May 16, 2012 11:06 AM, said:

Hello Folks,
I performed the mod, following the map the solering points/pads to a cartridge slot of an old non-functional atari2600 I had laying around. But I made a mistake of oversoldering the J3 pads and eronding them, so I tried to uncover the trace leading to such pads but I was not sure if I was accurate with the uppder pad. I would like to know if there is an alternative spot equivalent to the upper pad of J3 so that I could hook the wire there.
thanks

By upper, do you mean pad closest to the joystick ports? That appears to be ground.
The one closest to the epoxy blob, appears to come FROM the epoxy blob, so you would have to scrape the trace.

ATARIAGE FOLLOWUP WITH FLASHBACK 2 ISSUES
Sorry for not having catched the response before. The flashback2 I have has silkscreen with a table of corresponding values and has pads with numbers in the back of circuit board to as a reference for the cartridge connections, but the soldering pads/points are in different positions from the ones I saw on photos here on the forum, maybe I have different circuit board revision (hopefully mine is now a fake one). The following is a photo of mine with some indication:




By upper pad I mean the soldering point pointed by a yellow line with a number 1 (pic above)., and I tested and there are indications that it may be a ground. The 1 and 2 marked numbered yellow lines ( added editing the image) are only to help visualize are equivalent to J3 on circuit board and they the ones I messed up and eroded the plated soldering point by overheating them, but I believe that I was able to scrape some of the mask of the circuit board trace and was able to solder it there (but not I am not 100% if I got the right trace).

Another object of confusion for me is the soldering point/pad 21, it is pointed on the pic above by a yellow line and the no. 3. In my circuit board the silkscreen no. 21 is surrounded by soldering points so it is not clear to which soldering point does the no. 21 refers to.


Thanks for any help

Your 1. is ground.
3. is wrong. Should be to the left with the white circle around it.
You should have connection 20 (to the left of where 3 should go) to the 5th point from the left of the bottom right of the built in ROM chip.