Turbo Express Display Problem

[gzsfrk]

Hello hardware gurus!

 

Got a problem I was hoping someone might be able to help me with. I have a Turbo Express I picked up about a year ago that's now having issues. But first, some background on the unit.

 

When I first bought it, it was having the usual "weak sound" issue. In addition to that, it had a weird condition where, after turning it on, it would sometimes need to sit running for 30 seconds to a full minute before the LCD screen would "wake up", let's call it. Of course, I was able to fix the audio issue by replacing the related electrolytic caps. Audio still isn't super strong like an Atari Lynx, but was good enough that I could play it without headphones in a reasonably quiet room.

 

So today, it's been 2 or 3 months since I got it out to play around with it. But on a whim, I decided I wanted to enjoy some Devil's Crush on the small screen, so I pulled its carrying case off the shelf, popped in some fresh AAs, and turned it on. And while the audio kicked in just fine, with the game playing in the background, the screen stayed lit but black. At first I just assumed I needed to let it run for a while, like before. But even after leaving it running for over 5 minutes, I still wasn't getting any display output. I'd read that sometimes running off the DC adapter's power can help, so I popped out the batteries and plugged in the wall wart. Waited another 5 minutes, but still nothing.

 

Any guidance here? I know there's more electrolytic caps inside this thing that I can replace on the PCB, but most of what I've read online seems to suggest that generally doesn't help with this problem. Has anyone else run into a similar issue with their TE or PCE GT that they were able to successfully diagnose and resolve?

 

Thanks much in advance for any help and/or suggestions!

 

- m@

[FABombjoy]

The majority of the time, replacing the rest of the caps will fix a no-image problem. At this time, pretty much every cap in every TurboExpress ever made is going bad and should be replaced.

[gzsfrk]

Good to know. I actually bought one of your TE cap kits a while back, although I only replaced the audio ones. Was kind of intimidated looking at the rest of them, wasn't quite sure I could get them all to fit. (Bear in mind that I did do a full cap replacement on one of my Game Gears.)

 

Any particular tips on squeezing the new, larger replacement caps onto the TE board? Or a before/after picture, perhaps?

 

Thanks for the reply, man!

 

- m@

Edited December 13, 2012 by gzsfrk

[FABombjoy]

Sure, I can send you a few pics in a day or so, but the short story is:

 

The 100uF caps should stand straight up, more or less in the same locations as stock

Everybody else should lay down

CC505 (by the ribbon cable) should lay away from the ribbon cable

 

Things get crowded by the power & audio jacks, but don't be afraid to extend the legs if you have to.

 

The top shield can safely be left off with no effect to the quality of the picture or sound.

[gzsfrk]

Awesome tips! Thank much, dude.

[feester]

You should check VR500 (located next to the 22uf cap) and measure the ohms. If this is low it will cause the screen to not work. The sweet spot is around 14.32

[feester]