Supergrafx Won't Power On, Please help

[xemption]

Hello, I bought a PC-Engine Supergrafx a few months ago off ebay. I have had it for a few months  and everything ran fine for a while but now the unit will not power up at all. I checked the video cables and they seem to be in working order as well as the power adapter to see if it was plugged in correctly. As far as I can tell it must be a power supply or board related issue because there is no LED light indicator for power to tell if the Supergrafx is getting power or not.   The power adapter I'm using is the type you can adjust the tip I got from Radioshack.....9V 300MA which this what the Supergrafx requires as it did not come with the original. I opened it up I have limited board knowledge but I know the capacitors seem fine (Non-Bulging on Top). However the piece where the power cord plugs into, the wires that go from it to the board look like the insulation may have been burned a tad bit, could this be it because Im not sure if it was already like this or not?  Not really sure what caused this, should I of used a downstep converter?  I thought it be ok without it here in the US on this system.  I'm not sure and if I were to get this fixed how much would it cost me to fix and does anyone know someone who works on Supergrafx systems? Just need a little help here Im hard pressed for answers to whats wrong, Any suggestions? Thanks a lot

[xemption]

Also I just noticed on the board that there is a fuse on the left side of the board that says 125v on the side, does anybody know what this does? Could this have anything to do with the unit not powering up if this fuse is no good?

[thesteve]

300 mA is too small of a supply, and likely burned out.
get a 9V 1A (1000mA) to replace it (possibly larger)

[SignOfZeta]

300 mA is too small of a supply, and likely burned out.
get a 9V 1A (1000mA) to replace it (possibly larger)

300mA will power a Core system without issue, but the SGX has a bit more draw so, yeah, the PS is probably just crapped out.

BTW, xemption, you don't need a step down converter. Converters go between the wall and the power supply. If you are in the US using a US power supply then that's all you need. Make sure the polarity is correct, that the mA rating exceeds the minimum and that the voltage is as close as possible to the spec.

[SuperDeadite]

The Fuse is the main fuse that protects the SGX.  If it's blown then it will need to be replaced of course.

[xemption]

Actually I made a typo there.... its a 9V 800MA Adapter I have.....is this still too small....I know someone said I need 9v 1000MA so is 9v 800MA not sufficient? And in this case is it blown or just I need a new adapter? It worked fine before.

[xemption]

So what AC adapter should I have for this console and at what rating? I was just using the similar one that came with my console which was a UK adapter so I bought this one which matched it at 9V 800MA so this is the one I got, if not what is the correct one. So would this cause my Console to blow or is it just the AC adapter is now a dud and I should get a new one at 1000MA or over? Just trying to figure out which is the real issue, the adapter or the console itself. Really appreciate the help guys.

[thesteve]

800mA was likely good enough.
the supply could have died and needs testing even if not overloaded.

[xemption]

So Im guessing something went wrong on the console itself, does anybody know anyone who fixes Supergrafx systems?

[Chuplayer]

Got a multimeter?

Continuity check the fuse.

Check the voltage of the AC adapter under no load. Check it under load if you don't see anything out of the ordinary under no load.

The burned wires/traces sound odd, too. Maybe continuity check that stuff as well.

[xemption]

The fuse is fine, checked everything else seems ok too.......I'm gonna either have to send it in for repair or call it a loss. Can anyone here recommend anyone that does repairs for Supergrafx?

[SignOfZeta]

I've never heard of a broken SGX. Do you know how to properly check the power supply? Because, that's almost certainly the problem.

[thesteve]

I do repairs here, as do a few others.
having no info on dead SGX means nobody can give you a price/diagnoses up front.
i could likely fix it, id just need to figure it out as i go.
PM me if interested

[BlueBMW]

Id get ahold of thesteve.  He could probably figure it out.

[SuperDeadite]

Probably not the issue, but my SGX died once after I RGB modded it.  It wouldn't turn on,
nothing.  On the bottom of the SGX is a very thin grounding plate (not the RF shield), that's
soldered to the board.  Originally when I screwed the SGX back togeather, I put the screws in too
tight and it cracked one of the huge solder globs holding that plate on.  After I reflowed it, problem
solved.  Probably not your issue, but something to check as it breaks easily, and system will appear dead
without that plate.