GG overheating

[brettlee]

Hi fellow hardware experts! I'm new here but been following this board for awhile. I'm now having a problem with my GG after performing a total cap replacement on it. I have not tried playing that GG before because the screen was dead when I first got it, so I'm not sure if it could've been an existing problem before I did the caps replacement. Anyway, the GG overheats fast on the left side of the LCD leg. I noticed this after I played for a good 10 mins, and I felt the ext port was very hot, and then opened up the GG and realized that the heat was coming from that LCD leg! Also when he heated up, the game would start to behave strangely.. and freeze midway. I guess the thermal fuse on the LCD leg is still functioning, otherwise I would be getting a black screen.. Hmm.. perhaps there's a surge of power somewhere? Maybe some caps in the power board has died? Or, could I have accidently burnt a tiny resistor somewhere? Hmm..

This is the earliest version of GG back in 91, and has 2 ASIC chips. Judging from it's age, maybe the caps might have gave up now?

Any suggestions/feedback here would be very much appreciated! Thanks.

[brettlee]

Some update. I just re-soldered all the caps again just to make sure I didn't accidently bridge any connection anywhere that could cause a power surge. It was a failure and still the GG is experiencing the same problem. What I did at first was remove the caps one at a time, and powered it on to see if there's any difference. The same sympthom persists, the LCD's left leg still gets heated up fast, and the game would behave strangely. What I noticed is that if it warms up to a certain degree, the game would run normally but by that time the LCD would have been able to fry an egg!

Do you guys think that the FU2 fuse is malfunctioning? Oh yeah, the screen also gets much brighter on the left side, where the overheated leg is located..

I also swapped the power board with another working GG unit and still the same is experienced. So it's not the power board as I suspected earlier. Something Somewhere in the main board is pushing too much current to the LCD's left leg..

Again would appreciate any feedback here. Thanks!!

[Fix_Metal]

Maybe some resistor has lowered its impedence due to its overuse?

[viletim]

Replace the fluorescent tube.

[brettlee]

Maybe some resistor has lowered its impedence due to its overuse?

Hi Fix_Metal. Thanks for your respond! Hmm.. I thought so too.. But it would be tough to check every tiny resistors on the GG

But then again, this GG looks as if it was rarely used. Hardly any scratches on the screen. Very minimal wear. I might have accidently killed a resistor somewhere?? *Gulp*

[brettlee]

Replace the fluorescent tube.

So you suspect it's the tube that's misbehaving? Alright. Then time for me to scout for another GG for replacement parts!

There's a strange observation though.. Seems that the only game that would hang that I've tried so far is Sonic 1.  When you first see the Sega logo.. And the speech comes on, it will be heavily distorted, sometimes reduced to a beep and when the game goes into demo mode, there'll be white boxes everywhere and Sonic would sometimes jump on invinsible spring pads.. and goes crazy .. before the games halts and forces you to turn it off.

Another game I tried, Sonic 2. Seemed fine.

Sometimes, the Power LED will blink too...

Does it still sound like a Flouro tube problem?

[brettlee]

Ok, I did some research online, and came to discover that the flouro tube used in GG is a cold cathode type :

http://www.rpc.com.au/products/lights/coldcathode_faq.html

It mentions that it would fail if either lower/higher than rated voltage is used on the tube! I didn't mentioned that I DID play around with the voltages when I first got the GG. The first time I plugged in 9V to it, it would display some image and after awhile, white vertical strips started appearing and then the whole screen goes green. I then tried to power it on again, and it turned itself off after 2-3 seconds. Then my silly smart-ass mind decided to try a higher voltage, 12V, thinking that maybe the failed capasitor needed the extra charge, and well. The screen did come back at 12V. I was playing the GG for a good 15mins or so before it permenantly went green again..

I think this could possibly be the reason how I fried the tube... Correct me if I'm wrong? I thought the GG would know how to filter it's voltage? Or have I got it mixed up.. It would only know how to filter the current?

[Fix_Metal]

why overvolting a console?

[viletim]

brettlee,

Game Gear has a switch mode power supply, input voltage can vary over a wide range. For the backlight it uses a normal fluoro tube, just like the one in the ceiling. Pull the board out, unscrew the LCD and have a look at it. If it's unevenly lit or getting hot it needs to be replaced.

[brettlee]

brettlee,

Game Gear has a switch mode power supply, input voltage can vary over a wide range. For the backlight it uses a normal fluoro tube, just like the one in the ceiling. Pull the board out, unscrew the LCD and have a look at it. If it's unevenly lit or getting hot it needs to be replaced.

Ok! I will scout for a replacement tube soon. Thanks for the input viletim! Greatly appreciate it..

[brettlee]

Hey guys. Turns out that they were 2 separate problems! What I did last night was removed the fluoro tube and the strange Sonic 1 problem still persists!

I've posted a video to demonstrate this problem on YouTube. Please check it out

http://www.youtube.com/watch?v=0Yr-0yzoqPU

If any of you guys here has a older 2 Asic GG (with flat glass cover), please help me do an experiment and try out Sonic 1 cartridge. I'm not sure whether it's some special startup code that it uses or something else. I tried this very same cartridge on my other black 1 ASIC GG and it never fails..

Let me know what you guys think..

[brettlee]

I have replaced the flouro tube and so far it's back to normal operation. Doesn't overheat anymore. However the weird Sonic problem is still showing. I'll capture a video of it tonight. I tried it (the very same cartridge) on another White-GG and it's all working fine there. Well guess another option for me is to find one more Sonic cartridge and see if this problem can be simulated ..

[brettlee]

Craps. I'm just gonna assume it's a weird Sonic cart that i've got. Other games seemed to run just fine. So case closed
Thanks for looking.

[jetblue]

eeek, just like my problem GG. i have been away from the forums too long. Been working on other projects while i gather the things i need to fix it.
where did you find a source for the fluro tube?

nice vid you made 

[brettlee]

Haha.. Dude, just buy a used GG.. whether it's broken or untested and desolder out it's tube.. Chances are, they should be still working. I think it's very rare for the tubes to die? I could be wrong but this is the only first time I encounter a GG with this problem..

[jetblue]

were there any part numbers on the tube?
il desolder my tube over the weekend and start looking for a broken unit.