Help to fix a Bad RGB Mod for Supergrafx

[Shiver_169]

Hi
A friend recently sent me a Supergrafx that I recently bought and told me that he would use a Super SD System 3 with it to be able to access the entire catalog so I needed to remove the RGB mod that had been placed on the console. I opened it up and found a really horrible RGB mod with poorly connected cables and using epoxy to hold the cables and even worse they had the luxury of cutting the composite video track to put the sync in place. When removing this horrible mod I thought it would be as simple as removing the cables and the PCB with the amplifier used for the mod but it was not that simple. When removing the cables with great care, I noticed that there was severe damage in the tracks of the RGB and Sync signals, apparently they got too hot which ended up breaking them and not only that there is damage between pins 44 and up to 52 where of In fact, there are no longer pads to which the legs of the Hu6260 Chip can adhere, I restored the tracks using cable and I got continuity between the chip and the corresponding pins of the expansion port, but when testing if everything was fine with an External RGB board that it is put through the expansion port I just don't get any signal. I know the console is fine, why when removing the mod I restore the composite video track and with a Sega Genesis cable I verified that the console works well with composite video but the RGB just seems to be dead. I already checked if there were no bridges or junctions with some pins attached to those of the RGB and Sync signals and everything is fine, I even tried placing the same amplifier and the RGB video still does not work. I've been with this for days and I can't find something is wrong, I don't know if any leg of the chip is wrong or needs 5V as the chip diagram says, hopefully someone can help me restore this beautiful console that a Pseudo Technician tried to modify for RGB. I will try to upload photos although it is complicated since I must do it on a suitable platform for it, I do not know if I can upload them to my Instagram and quote them here, I also hope your help with that.

Greetings and take good care of yourselves please.

[NoAffinity]

Did you test it before attempting the repairs?

If all connections are restored and you have sync going to the correct pin at the output, then non-functionality would point to something like an ic being damaged.

Imgbb.com is free and gives you multiple options for links that can be posted on this forum.

Sent from my SM-G955U using Tapatalk

[Shiver_169]

Did you test it before attempting the repairs?

If all connections are restored and you have sync going tot he correct pin at the output, then non-functionality would point to something like an ic being damaged.

Imgbb.com is free and gives you multiple options for links that can be posted on this forum.

Sent from my SM-G955U using Tapatalk

I'll be honest I didn't test the console because I didn't have the right cable and I didn't want to modify one.

I already uploaded some images, I leave the links to them and I hope they tell me what else can be done.
https://ibb.co/vPF8VTJ

https://ibb.co/92F70S8

[NoAffinity]

Well, without a known good console, you could be chasing problems that arent the real problems.

But, going from the pictures, it looks like red might be shorting to one of the adjacent pins. In the second pic, have you reflowed the questionable area with flux? It looks like there could be a bridge behind some of those pins. An adequate amount of flux and some proper reflow should ensure that's not the case. Also any traces that go under the ic and have pads missing, you may be out of luck on. Hopefully someone more familiar with the trace routing can give some assurances that none of those traces run under the ic.

Sent from my SM-G955U using Tapatalk

[Shiver_169]

Well, without a known good console, you could be chasing problems that arent the real problems.

But, going from the pictures, it looks like red might be shorting to one of the adjacent pins. In the second pic, have you reflowed the questionable area with flux? It looks like there could be a bridge behind some of those pins. An adequate amount of flux and some proper reflow should ensure that's not the case. Also any traces that go under the ic and have pads missing, you may be out of luck on. Hopefully someone more familiar with the trace routing can give some assurances that none of those traces run under the ic.

Sent from my SM-G955U using Tapatalk

The first step I did was to check short circuits with pins attached to the RGBS signal lines and I did not find anything, although I will try to put a little more flux and with it remove some rest that is behind the pins. Now I have already reviewed the diagrams of the Hu6260 chip and the console and in theory the signals go directly from the IC and go to the expansion port so simply restoring the broken tracks should be enough. Is there any way to verify IC operation?