The only Vintage Game system or computer I have kept is my Game Boy DMG model. Based on the serial number I am guessing it was built in mid 1990. I had it from new and put a lot of hours on it playing games. It has seen better days. It was kept inside a case and never it an attic where it got hot. The case is pretty close to the original color, maybe some light yellowing. The display was missing lines, the glue failed on the screen cover and it fell off. I tried to glue the screen cover back on with super glue at some point, that held it some but ruined the “paint” on the under side of it.
The audio was being flakey at times on it at times. The screen even when it had the lines was well a DMG Screen.. I picked up some parts from Console 5 and somewhere else possibly on Ebay for my first pass of working on it.
So just as I said “first pass” Almost nothing in this picture ended up in the Game Boy well ended up remaining in the Game Boy. I’ll go over that anyways. The new Glass Screen cover, replacement Volume pot, Cap Kit. Button pads, well they were the wrong ones. Then also a back light kit with the Bivert board. Finally some Triwing drivers. It turns out my early Game Boy doesn’t have a single Triwing Screw in it. It is all Philips screws. It isn’t in the picture, but as I had concerns about audio I did get a speaker as well.
It wasn’t too bad to clean up the old screen, you can see where the glue I had stuck it back on with years ago pulled he old paint off the back of the plastic screen. I did have an issue with the new Glass Screen though.
So the first pass I went with the Backlight mod and the bivert board. The board was great. The removal of the old reflective layer was bad. Looking at the before picture, my screen wasn’t the best to start with.
Installing the board went very well following the provided instructions. There are 2 pins there to lift on the display connector on the CPU board side. The board is basically a carrier board for an inverter ic, the chip inverts the display. The light areas become dark and vice versa with it. With the Back Light rather than the reflective unlighted screen it makes it look better. The next part of the process was to take the reflective layer from the back of the LCD Screen. It was very tight, and while I got it off in the end the lcd was in worse condition afterward with more missing lines. I have seen people manage to repair the missing lines, but mine have been going bad since back when I was still using it in the 90s. Even so it looked so much better with the backlight.
Yes it is missing more lines and even a couple horizontal lines now. Yes the Glass Screen broke installing it. The screen broke because it was very slightly oversized. I installed most of the capacitor kit, with the ones on the LCD, Power, and Audio boards. I tested the new ones and the old ones at the time on my component tester, none of them appeared to be bad. I left 5 of the 6 capacitors on the CPU board alone due to that and being disappointed in the outcome of the screen, the glass and the fact that the audio issues didn’t clear up with the new capacitors.
Well even in that condition the Game Boy was improved. I played it a bit like that. If the LCD wasn’t missing so many lines I would have kept it that way. It looked so much better and I wanted it keep it near original. That is why I didn’t go with one of the full LCD Replacements.
With the LCD not working out though, I did end up getting one of the Replacement IPS LCD kits.
The instructions for it worked out very well. This is an old project that I didn’t document much. I did take a few before and after pictures. I would say the kits were fairly polished when I purchased mine, and they have been refined since.
The IPS Screen looks great, and has various color options to choose from. It doesn’t have the ghosting of the original lcd, which is a nice plus on fast moving games. The IPS Screen is the V2 or V3, which is now an older version of the screen, I am sure the V5s are nice these days. I put this in a few years ago now though.
Once the IPS went in the screen looked good minus the cracked glass cover. To fix that I ordered another Glass cover, this one was also oversized, I filed it down with sandpaper on the edge to get it to fit. I purchased a few more games for it to play with.
I was still having issues with the audio and it was getting worse. It would often not be working at power on, and then it may start working after a little while. With the audio getting worse I packed it up and let it sit in the case.
With Joes Super/Game Boy Console project catching my interest I wanted to see if I could finally get my DMG back to full proper working order. Initially I thought maybe it was the audio jack. The Audio Jack has a switch built into it, when there are headphones plugged into the jack the internal speaker is disabled. I also wanted to look at the capacitors that were replaced and the ones that weren’t replaced. Looking at the Schematics for the CPU Board, the electrolytic caps are mostly audio related. Because I was working on the Super Game Boy Console, I let the DMG sitting in the case mostly. I wanted to add the Multiplayer Game Link function to the Super Game Boy Console, so I didn’t want to risk breaking the DMG before I could get that tested. I finished up the Super Game Boy Console recently (check my post about it if you are interested).
Last week after getting the SGB Console done and the Multiplayer tested I took a look at the DMG. The audio is completely dead out of the speaker. I plugged in head phones and only had one channel of the audio and a lot of buzzing. I then took it apart, looking it over I didn’t see anything obviously wrong. The capacitors that were changed looked fine. I was able to tell that the CPU Board had 5 original capacitors still on it, as only one was replaced on it. The Audio Jack which was still a question for me has a lot of oxidation on all the exposed metal on it. I have seen other connectors do this at times. This socket has a switch in it that disables the audio. I had previously tried to clean it with contact cleaner but nothing changed.
Today I went to look at it further. I replaced the 5 remaining capacitors on the cpu board. I did test the capacitors I removed and the new ones before installation. With the tester I have for them, the old ones appeared to be fine. I did put quite a few hours on the Game Boy back in the 90s, but likely no where near used them for their rated hours at the temperatures the Game Boy runs at. I probably wouldn’t replace the Capacitors on at DMG again anytime soon. I don’t plan to get another one either though. Certain hardware from the later 90s has bad capacitors in them due to defective design or bad mix in the electrolyte etc. I also feel capacitors from the early 80s especially in equipment that gets quite warm, will have a greater chance of being in need of replacement. In some of my retro computers or devices I have found capacitors that even my limited tester indicates are out of specification.
I looked over the boards again, but didn’t find any visible problems. I did clean up and redo some solder points, redid the power switch, the Link Port and some other solder points incase they had been stressed although I had not seen any visible cracked solder around any of the pins. I cleaned the tarnish off the exposed metal parts of the audio jack. I then removed the audio jack from the pcb with my desoldering gun. It shouldn’t have been awful to get off with the solder sucker. I tested it, and none of the pins were connected once it was pulled out. Checking the schematic, and tracing the wires I found that pin 6 of the audio amp is to be switched to ground, and that is the pin of the audio jack that goes to the white wire on the audio board. Testing again on the jack there was no continuity to the other half of the built in switch. I plugged in a 3.5 plug and it didn’t connect the switch. I was just able to see where the switch moved when the jack was inserted. I sprayed it with contact cleaner and used an Xacto blade to get a little under the switch. I was able to get the contact working again spraying it again and using the 3.5 plug in and out a number of times. I tested and had under 2 Ohms then. I also tested the 3 connections on the 3.5 plug and all are making good contact now. I then soldered the jack back onto the pcb and retested the switch and 3.5 plug contacts again.
I have some other pictures of the boards before cleaning off the flux and reinstalling them. While I had them out, I put contact cleaner in the Multiplayer Link Port, the Volume pot, Power Jack and Power Switch.
The internal speaker worked properly again after reassembling the DMG. There is a bit of hum, but that is mostly from the AC Adapter, when on batteries there is nearly no hum. I don’t remember the hum being there in the 90s when using the same AC Adapter. It may have an issue developing, I will probably check it with the scope and see what the output looks like. In looking into the hum, it was reported that the IPS LCD kit adds some Hum to the audio, due to higher current draw, well that is what they said. Maybe it also is making some of it due to intefearance from it’s operation being picked up in the audio amp or something. It is not very bad, but certainly is more present when on the AC Adapter. It was worse actually before cleaning the power port, power switch and other contacts, I thought it was from the Audio Amp itself, but it was that same hum just worse before working on it this last time.
The Directional Pad didn’t work properly though. While I had it apart, I had switched out the contact silicone pads, the Start, Select, A and B buttons all worked properly with the new pads. I took the DMG apart again and checked the pads. I cleaned the contacts on the PCB. I then tested conductivity of the new Directional Pad and also the Original Pad. The Original Pad was more conductive. I cleaned it lightly with IPA and reinstalled it. I also looked at them, and the new pad is designed just a bit differently. I tested the DMG again and the directional pad was working properly. I had swapped them as they are old and they look worn. It also seemed the directional pad wasn’t always working as well as I liked. It seems fine for now though after cleaning, hopefully it holds up.
The volume control is good and smooth, it isn’t scratchy at all. The power switch works properly making good contact, and the power jack is giving good connection too. The power cord could give some crackling before as it swiveled in the port on occasion before. It seems everything is finally working properly again. I’ll get a chance to play the old DMG again.
Looking at the photos from when I started working on the DMG, it has been over three years since I put in the Back Light mod and started putting the capacitors into it. It is nice having it finally sorted out and in good working condition again. Now I can pair it up with my Super Game Boy Console and play some two player Game Boy games.
Muldrf's Hobbytronic 