Messages

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

What of the poor TE, though? ) :

It has a mainboard problem that I couldn't resolve...... so it's now relegated to a spares unit. 

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

I grabbed my nuts and took a RAM chip off of a TE and replaced one of the RAM chips on the CGII.  By luck it was the faulty RAM chip and normal service has been resumed.

 

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

Ahh good point.  I have a more or less knackered TG so I could use that as a donor if needed.

Nothing of use being returned on-line against those chip references unfortunately.

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

Thanks for the offer (yes I'm in the UK), however I suspect once I'd sent it and paid for return back and your time, I'd be better off buying my own logic tester.  TBH getting hold of replacement RAM chips is probably not that easy either.

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

I only have a multimeter I'm afraid.

[Console Repair/Mod Center / Re: Corrupt graphics on Core Grafx II]

Graphics are corrupt even with a Super CDROM2 game.  If I swap the engine out with another, everything is fine.

Flashing pixels and vertical lines are quite commonly related to RAM issues afaik, which are the problems I have.

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

It's not an OE screen I need.  Something is obviously mullered with my main board, even after looking at the areas you suggested, I didn't get anywhere.

[Console Repair/Mod Center / Re: PC Engine GT / TurboGrafx Express repair request.]

I've dealt with that sellar as he supplied me a full cap kit.  Service is perfect and quick.  For £15 I'd use him for the full repair.  I wouldn't be bothering again for the sake of £15 all in.  It's a no brainer tbh.

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Thanks for that link..... where are the screens available from?

[Console Repair/Mod Center / Corrupt graphics on Core Grafx II]

Just fired up my Core GFX II today and appear to have corrupt graphics.  Opened the unit up and can't see any obvious trace issues and I reflowed the solder on the RAM chips.

Any advice or guidance?

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

By tweaking VR500 I can just about get to 14v.

Apologies, not sure what you mean by "check". 

All caps have been replaced and it's the same problem I had prior to the cap replacement.

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

First unplug the screen and recheck (keith had a shorted screen)

Around 11.6v with the screen unplugged.

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Any pointers on how to resolve this low voltage issue? 

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Not sure at the pot
You should have -24V at the - pin of the 22uf cap near the pot 2

11v measured at that point.

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Thanks for the feedback.

IIRC when I measured the voltage on VR500 it was only around 10v.  I'm assuming this should be 24v.

Any pointers as to how I can perform further diagnostics and/or fix the supply problem?

(Thanks for the reply to my PM btw) - In the PM you mentioned about a possible arcing.  What should I look at to establish if this is taking place?

I've placed an order for replacement Q900 and Q901 transistors, but I'm assuming this will not fix the issue?

[Console Repair/Mod Center / Re: REPAIR GUIDE - TurboExpress/PC Engine GT: Video Fix]

Hi,
I seem to have the same or similar problem as Keith Courage reported above.

I had previously changed the video cap a few years back - that resolved an initial dim screen issue I had. 

Recently I tried the GT and after 10 mins the screen went very dark.  Because I also had low sound, I thought I would complete a full recap.

After the full recap I still have the same screen issues:

The backlight is working - although very dim.
You have to extremely tilt the unit to see anything - this gets worse within minutes and then backlight shuts off completely.

Any help guys?

Regards,
Shaun