3 Game Gears, 3 different problems

Found 3 and all 3 has different issues.

First one is a Majesco model (black shell, 3 white oval logo, one purple button). Display is bright and nice, almost like it's new. But buttons 1 and 2 does not work. Took it apart, it's missing rubber domes. Original caps still there so it'll probably get recapped soon before it goes bad.

Second one is single ASIC version. Mostly worked but display goes from too-dark (mid point on contrast dial) to completely dark. The dial when turned other way from midpoint to max setting, nothing changes. Either the dial is dirty or broken or something between the dial and the LCD is not right. Does have new caps, all caps checked to be in correct orientation. They are not the square ones Sega originally used but round radial style caps. I didn't check the brand so if it's shitty brand I may recap it first then check the dial.

Third one is twin ASIC model. No game image, only blank flickering screen. Original caps. Probably needs recapping.

So is there a reason that GG #2's contrast dial goes from half way to completely dark and not have working brighter level? Assuming the caps is not the issue, where to start checking?

Majeco GG- where to get replacement domes? I'd rather try to get all 3 working but if one is a hopeless case I can scavenge the domes. Assuming that the rubber domes are all the same regardless of GG models.

 

Ok so for the first one you'll have to scavenge some off a game gear that doesn't work.

For the second one my money's on the dial/pot being bad. Try spraying some WD-40 on it (with the system turned off of course!) and twist it around then let it dry. If that doesn't do the trick there could be 2 things wrong, one would be the
capacitors will need to be replaced (if they are cheap) or it could be that one of them isn't making good contact on the pads. There are four capacitors in charge of the screen brightness? (I think that's what they control) and they are located on the bottom left close to the middle. The second part could be that the backlight could be going bad but I haven't seen that yet. Could also be some traces that were severed when replacing capacitors or when they were leaking.

The third one just needs new capacitors then it should work.

Quick Edit: There appears to be some rubber pads listed on ebay, however for that price you could probably buy a broken game gear.

http://www.ebay.com/itm/Button-and-...air-Part-/400800821161?_trksid=p2054897.l4275

 

Game Gear still pops up at local thrift shops and it's usually less than just those parts. Guess I'll scavenge.

I got #3 working fine now after recapping (lucky me I made a mistake and ordered extra kit from console5) I did not recap the sound board as it had solid state caps which seems to be unlikely to fail anytime soon. Beside they're a bitch to replace with regular leaded caps.

I'll probably scavenge from Game Gear #2 for the domes and turn that GG into console version. Don't need working LCD or dial anyway. All I need is a way to get nice looking case shell without any plastic forming experience or access to 3D printer. I may need to brush off wood working skill. Consolized GG + Everdrive = dang near any GG and SMS games playable, I can remove the bulky SMS console from my shelf (SMS2 is rare and damn expensive, and removing 32X for power base converter is a pain in the ass with 20 cables in the back to change around)

Schematic for twin ASIC doesn't seem to exist anywhere, I've searched. Schematic for more common single ASIC is everywhere and it would be easier to mod the stripped down GG unit to remove redundant parts related to LCD with schematic.

PS anyone know of making custom plastic console guide? 3D printer still costs a few hundred minimum and may not be big enough for a GG case. I don't have equipment for vacuum forming or anything else. Never tried to use 3D CAD to design one either

 

If by solid state capacitors you mean the SMD ones then I would recommend you replace those too. Those are bad as well. My technique is grabbing some needle nose pliers and gently wiggling them back and forth until the leads break. Then I use solder wick to remove the old leads and solder. Haven't ripped a pad with this technique yet!

 

They are probably SMD. Very small, silver metal can, solder on the base. I'll get those replaced then.

 

Don't use WD40 on pots - horrible stuff. Use proper contact cleaner - switch cleaner is usually lubricated, so that's good.

The surface mount caps on audio boards certainly need replacing, just like any electrolytic. I use surface mount caps, but most don't bother.

 

Bit of a good news, the second GG worked fine after all. I noticed the display flickred when I touched the ribbon cable. When I held it in a certain way, I was able to get normal display and the dial worked fine. It seems there's a bad connection on the ribbon cable, probably the one that feeds power to LCD.

I'm still going to take the LCD out and get RGB board in and make this one consolized. Too much a pain in the ass to repair flaky ribbon cable.

 

Depending on where the loose connection is, it is possible to resolder the cable onto the board. I've transplanted a game gear screen before.