Supergrafx white screen

[Jeff]

Hello,I am a new member and I am having trouble with my supergrafx.All I get is a white screen when I insert a game and switch on.Machine has been received capped.Still white screen.Wonder what else could be a miss.Graphic chip blown maybe ?Any help would be most appreciated.

[CrackTiger]

Try the PCE/SGX mode switch (on the back?).

[Jeff]

Try the PCE/SGX mode switch (on the back?).

Hello,I tried the switch first.Definitely not that.Thank you for the reply though.

[BlueBMW]

Is it possible the unit experienced some sort of a physical shock?  Supergrafx are notorious for the mainboard cracking in the middle by one of the support posts.  Cracked traces can cause any number of not working conditions.

[Jeff]

Hello,checked the board and all looks in good condition.

[Bloufo]

Could be a case of that the games are going in too far in the slot. Back them back out until the power lock just barely clears the card, then turn it on.

[Jeff]

Thank you,I will give that a try tomorrow.

[TurboXray]

I dunno. Sounds like dirty pins on the connector. I've had this happen to my SGX when I didn't play it for a year (the humidity of the swamp cooler during the summers, is the culprit I suspect in my case). Anyway, but yeah, dirty contacts is a somewhat common thing with SGX/PCE/TG16 consoles.

[imparanoic]

check the power supply is correct Output DC 9V 800mA (higher milliamps is fine, but lower will ruin your machine)

[Jeff]

Thank you for the replys.I have cleaned the contacts and power supply is correct.

[deubeul]

Do you have several hucards to test?  Bloufo's advice could be right, sometimes the Hucard position could be picky.

BlueBMW is right too, I once had a crack on the MB of mine because of a not so big shock, the crack was under the card slot and hard to see.

[Jeff]

I have checked the board but will look under card slot.Thank you.

[majors]

... power supply is correct.

I had a Shuttle using a random PSU from a old pair of computer speakers that was rated correctly based on the label. The volts read correct but it never worked. I found another that worked so I can only assume the amps was too low on the first one since it quite old (I could not test that with my multimeter). Is the PSU original? If cleaning and checking the mobo check out, can't hurt to test with another power supply.

I would get a green-ish screen with a slight fade to blue near the top using the "bad" power supply.

[thesteve]

Cracks are most likely
They also crack by the heatsink screws in

[Jeff]

I have another supergrafx and use the psu from that one,so don't think that is the problem.Tried the game cards further out and in to no avail.Thank you for suggestions though.

[Jeff]

I have has a good look at the pin conecter and it does not look the best.Does anyone know where I would get a replacement.Think that is worth a try.I am in the UK but don't mind if I have to source one anywhere.

[Jeff]

Does anyone know where I can get a replacement pin conecter from?that's worth a try.I am in UK but don't mind if I have to get one from elsewhere.Thank you.

[Jeff]

I have a core grafx also and wonder if the pin conecter is the same as in the supergrafx?I could use the core as a donor for the supergrafx?

[BlueBMW]

Unless you have bent / damaged pins, its usually not necessary to change out the card slot itself.  The Supergrafx card slot is unique in its shape compared to the other systems.  You might be able to make something work, but a direct replacement would have to come from another supergrafx.  It may be worth checking continuity on each trace from the hucard slot pins back to wherever they go.  Like steve and I said, cracked boards are rediculously common on the Supergrafx and it can sometimes be hard to find.  Even a tiny crack can break a few traces but barely be visible through the solder mask.  Best of luck!

[schweaty]

Shine a bright light underneath the board.  Any cracks will be much easier to see

[Jeff]

Thank you for that,I will get the traces checked out and closely inspected for cracks.

[schweaty]

If you want to cover your bases as far as the card slot goes, you could reflow the solder on the connections, but that would be as far as I would go

[Jeff]

Hello,after all of your advice and knowledge I have left the idea of it being the card slot alone.I shone a torch behind the board and no cracks.But I did spot 2 wires adrift where the account power joins to the main board.These wires were intact before but maybe barely.I will get them re soldered and hope that is the solution.All of your help has been great.

[thesteve]

if you do have a pin bent in the slot that would do it
you could likely swap just the pin from a different slot

[Jeff]

Hello guys. I have had the loose wires re soldered on the ac power to main board. Still no joy. no cracks in pcb and traces all OK. No idea what else could be wrong.Graphic chip blown ?? Any help would be most appreciated.

[BlueBMW]

Your best bet might be to send it to someone like thesteve to figure out.  We've covered all the usual suspects.

[Jeff]

I will try that. Who is thesteve and where I he based ?

[BlueBMW]

Lookup his username on this forum.  I believe he is in California.

[thesteve]

thats me, yes im in cali