No video on Duo-R after S-video mod

[ApolloBoy]

Here's a real doozy that I've recently run into, I just finished modding a Duo-R for S-video and when I went to test it, I got absolutely no video whatsoever, even with composite video using an AV cable. I will admit that I accidentally bridged some pins when I decided to use pins 21 and 22 for 5V, but I was able to fix that problem with a little desoldering braid and there are no other shorts on the HuC6260 or anywhere else.

Is there a possibility that the 6260 suffered heat damage when I used that desoldering braid? I find it somewhat improbable since I didn't leave the braid on for very long and I didn't have my iron on a high temperature.

[PCEngineHell]

Usually the stuff can withstand some decent temps, but yeah, heat travels and if you had it on there too long damage is possible. If you can, scrub the area down then inspect it with a magnifying glass including to check and make sure all the pins are still contacting the pcb.

[turbokon]

Highly unlikely. I removed a hu6260 with a heat gun and put it back with no problem.

[Keith Courage]

I am not sure how or why but I came across a DUO where the composite no longer worked once. Instead of tracking down the problem I rebuilt the circuit using thesteves awesome video schematic that he uses on Turbo express systems. Worked like a charm

/16oqb5.gif

[ApolloBoy]

But for some reason the luma signal isn't working either, even if composite didn't work I'd still be getting a black and white picture through S-video, but that isn't the case.

EDIT: FIXED IT!! Turns out pins 39 and 40 were shorted and I didn't even see it, got them unstuck and it's working great now!

[turbokon]

Awesome!!

[PCEngineHell]

Sweet and glad to hear. Usually when I do solder work on pins I double check it with a magnifying glass and brite led light to checking for any accidental bridging or other issues. I ran into something similar on the last X-eye I svideo modded where composite failed on me. Ended up that a pin off the encoder chip lifted slightly off the pcb or something. I don't remember the nitty gritty but it was a easy fix. It was just one of those things where it looked perfectly fine until it was magnified.