Game Gear random shutdowns are NOT due to faulty caps + LED mod

[shadow460]

I have this model 1 Game Gear I got free years ago. I finally got around to installing a cap kit. It had been shutting off right after it powered up, and it still does that. Hmm. I recapped another Game Gear and that worked fine, so I know my work is good. Still looking for something to do, I grabbed up my one owner 'gear and swapped the fluorescent backlight out for four LEDs. I'd been having no trouble at all with this unit--I just decided to take the risk and do the mod.

 

It now exhibits the random shutdowns. If you turn the brightness knob on either unit, their behavior will change. Turning the brightness high on the broken unit will allow it to stay on until the brightness is decreased to a certain point, then it shuts down. My other unit, the one I instaled the LED backlight into, will shut down sometimes when the brightness knob is turned while a game is in progress. So long as I leave the brightness alone, it plays fine.

 

Therefore, I think the auto shutdown problems are caused by the backlight circuit. Perhaps they occur when once of the components in that circuit begins to fail. As with any compact fluorescent bulb, eventually the ballast will fail and the light will begin to flicker. Possibly when this happens it causes the unit's voltage to drop, which shuts the Game Gear down. It's also possible that the unit has some way to detect that the bulb or ballast is failing, and it shuts down automatically when that happens.

 

The LED backlight isn't suitable as a mod--it's only really suitable as a repair for a failed backlight. It left bright spots which aren't really that big of a deal, but they're there. The screen is generally dimmer, too, but it seems more defined. I've read it saves battery power, but I haven't run it enough yet to know. I got 10 to 12 hours on a charge before. If it's as good as what I've read, I should get 3 to 4 days continuous on a single charge. I'm not sure, though because when I compare light bulbs, LED bulbs and CFLs use about the same amount of power. I assume the CFL it had is an energy efficient bulb just by design.

 

We'll see how it goes, and I may be hitting some folks up for help with the random shutdowns if they begin to occur more often. I'm 100% certain it has nothing to do with faulty capacitors.

[Osgeld]

I am 100% sure the check engine light that is on in my car is not causing problems, but without actually troubleshooting it I will not know, it just acts grumpy

 

so you have a boost circuit that is more than likley self regulating now going to dead air, first thing I would try is to measure the output voltage of that circuit

[shadow460]

The random shutdowns stopped when I removed a 10 ohm resistor from the circuit. I have two sets of ... things ... in parallel. Each string consists of a 40 ohm resistor and two LEDs. The LEDs are wired in parallel in each string, but they're in series with the resistor. There are two strings. There was a single 10 ohm resistor between +5VDC and the point where both strings are fed. I removed that resistor and good things happened like the backlight getting brighter, shutdowns stopped, and bias voltage at 3.2 compared to the rated 3.3 volts of each LED.

 

BTW, the Game Gear now uses roughly 2/3 of the energy it did before.

Edited May 21, 2013 by shadow460

[xDragonWarrior]

I got a GameGear from a value village for $1 and it has random shutdowns also(the same ways yours does with the brightness).dont know whats cauaing it though.