Problem with Supergrafx (not displaying SG(or PCE?) generated sprites

Glossectomy · 05/20/2014, 06:13 PM

So I just received my Supergrafx console today, and I'm having some issues with it. From what I can tell, it's not displaying any graphics generated by either the SG side of the PCE side. They'll display as white or brown boxes. Like in Ghouls and Ghosts it seems to be the chests that don't display as well as the death explosion of the enemies. Battle Ace the enemies turn into large white boxes once they zoom in to a certain point. Mado Granzort doesn't display the "Press Run" and Husdon copyright on the main screen. Issue happens on both actual SG cards and a Turbo Everdrive.

I'm more than competent with a soldering iron and components, so if anyone knows what may be causing it I could definitely try and take care of it. I really don't want to have to return it because I got a fair price, and I would hate to eat the EMS shipping costs.

Any help would be greatly appreciated, and I hope this was the correct forum to post in. It didn't specifically mention Supergrafx, but I thought it fit here better than the SG forum.

Below are a few photos of the issues.

Thanks for looking

pulstar · 05/20/2014, 06:38 PM

First of all I'd clean the Hucard and the slot before doing anything else.

If it's neither of those it could possibly be a RAM or addressing issue. Do you have a logic probe or an oscilloscope? If you do get the datasheet for the ram and check all of them are enabled and the data lines are active.

Glossectomy · 05/20/2014, 07:15 PM

Unfortunately I don't have an occilliscope. I ceaned the entire board and still have the same issue. I'll provide some high resolution pictures in a few moments to see if anyone sees anything out of place. Everything looks good from what I can tell. Caps aren't bulging, I don't see any broken or corroded traces (one looks a bit off, but that's really it). There's a single red wire running from the hu card slot to the exp slot, but it looks like it was done originally.

Here's some shots of the board.

https://imgur.com/BANRaK9
https://imgur.com/wkD2Eod
https://imgur.com/aTyjb6f
https://imgur.com/itS4QLU

Another weird thing, the first time i tested 1941 on the everdrive it booted a black screen with nothing. Now Its playing fine from what i can tell. also i loaded darius plus and both my shield and bullet are displaying fine. I've seen someone break the layers of that game down and both of those seem to be generated by the Supergrafx. But the actual hucard still aren't working as they should.

pulstar · 05/21/2014, 12:10 PM

Having a quick check over the pics there seems to be 3 traces that look suspect on the top HuC6270 (IC108) - pins 1,2 & 3. If you've got a DMM do a quick continuity check on those 3 traces and see if they are all good.

Keith Courage · 05/21/2014, 02:53 PM

Yes, there are most likely bad traces from the video ram to the HU6270 chip. Do what pulstar mentioned. Or if you don't have a way to check for continuity then try bridging some wires.

Glossectomy · 05/21/2014, 04:27 PM

Those were the traces (2&3) that I thought looked iffy. Checked continuity and 3 wasn't making connection. Soldered some kynar wire between the 2 points, and its working beautifully!

Seriously, thanks so much guys.

Nazi NecroPhile · 05/21/2014, 04:35 PM

Well done, guys. Another one saved!

esteban · 05/21/2014, 04:55 PM

Fantastic.

pulstar · 05/22/2014, 05:19 AM

Cool. Glad to see you got it working. Now enjoy some G'n'G.

Tatsujin · 05/22/2014, 11:19 AM

super fix-fix

turbokon · 05/22/2014, 01:34 PM

Quote from: pulstar on 05/21/2014, 12:10 PMHaving a quick check over the pics there seems to be 3 traces that look suspect on the top HuC6270 (IC108) - pins 1,2 & 3. If you've got a DMM do a quick continuity check on those 3 traces and see if they are all good.

I don't know how you saw that. I can't see that close with my iPhone. Looks like you were spot on:)