SEGA Game Gear VA1 Schematic - HELP!

[3lectr1c]

Recapping a game gear, no problem. I've recapped a ton of stuff. While cleaning up the pads, a diode got knocked off the board. While cleaning up the pads for the diode, I accidentally created a solder short to a nearby component. I went to clear it with desoldering braid, the pad vanished. It's gone... Oh no.
Went to find the schematic to see where to run the bodge to and it's a low quality scan without any visual trace of where that pad goes to!

https://gamesx.com/wiki/lib/exe/fetch.php?media=schematics:service_manual_-_game_gear_va1.pdf

Here's the schematic, and a screenshot of the diode. Can anyone help with this?

 

[3lectr1c]

Here’s that area on my board. Looks like there’s something underneath but I’m not sure what. Looks like it goes to one of the middle board layers…

 

[twolazy]

I'll try to find my spare game gear board, I have 2 working units as well as a parts unit. Maybe tomorrow after work,I can dig out the spare board.

Is it a V1 or V2? V1 the screen protrudes/bubbles out a tiny bit, v2 its flat with the body.

 

[3lectr1c]

It's a VA1, 837-9024. Would love if you could do some continuity checking on that spare board to see if you can find where that pad goes to! Thank you so much.

 

[3lectr1c]

Here’s what the front looks like

 

[VERAULT]

Even though the exposed pad is gone, it went somewhere. Somewhere under the solder mask is the trace and its going to be next to where that pad was. Grab a needle and do a lil scraping. Use a tidbit of wire wrap wire to connect the other half of the diode to wherever the mystery trace goes.. let us know when you find it.

I have fixed two game gears with leaky caps but none to the extent of electrolyte damage yours has. Did you clean and neutralize the boards?

 

[3lectr1c]

I had thought of that. There appears to be something under where the pad was, hidden under some of the PCB. I’ll have a probe around tomorrow and see what I can find.

 

[3lectr1c]

Is it possible it connects to nothing?

 

[VERAULT]

no. it had to go somewhere

 

[3lectr1c]

Rats. Can’t see where that would be. Any ideas where I should probe around with my scraper?

 

[3lectr1c]

Dug around a bit more… just no metal in sight.

 

[VERAULT]

upload a photo with circles over where the two pads were

 

[3lectr1c]

Top right one is the broken one. 3 pin SMD diode. I’ve got the diode still and it appears to be intact. Wouldn’t take more than warming up my SMD rework station to get it attached…if I knew where it connected to.

 

[VERAULT]

wouldn't it be a transistor with 3 pins? I could very well be wrong on this but I never saw a 3 leg diode yet. your best bet is to stop work and find out from another board. Scour photos online or ask someone to let you know.

 

[3lectr1c]

It's labeled D4, not Q which I believe is the notation for a transistor?
Looking it up, the component looks exactly like this: https://www.newark.com/infineon/bar6404e6327htsa1/rf-pin-diode-dual-series-1-35/dp/50Y1731
I honestly don't know though, I'm not an expert. Won't be messing with it further until twolazy gets back about his spare board.

 

[VERAULT]

Well I learned something new and I think this is good news (hopefully someone else can back this up but I think because of its nature that 3rd pad that fell off was not connected to anything. The large pad and the small one should be all you need.

 

[3lectr1c]

Oh that would be amazing news if that was the case! Yes, for sure won't be testing anything until someone else confirms. I've got a couple days though before my cap kit comes in from console5, so I've got time. In the mean time I better get on with cleaning up the solder pads on the sound board, and removing the old caps from the DC board.

 

[twolazy]

Ok dug out my spare board, and seems to be a different revision. It has no D4 in that area whatsoever and a inductor next to r29, which yours does not have. I'll dig out my 2 good Game Gears tomorrow and open then up. Upside the diodes on the board look identical so i can remove them and send you them to repair yours.

 

[3lectr1c]

I’ve got the diode still, that’s no issue, I can reattach it with my rework station. All I’d need help with is figuring out where the pad went, if anywhere at all

 

[twolazy]

On the backside of the gamegear is the black sega sticker. What model does it show on it? Parts unit and my spare working unit are 2110. I'll have to dig out the one in the travel case this week, think that is an earlier one.