Tech Notes:
This page is dedicated to those on RGVAC who have saved me countless hours of troubleshooting and $$ on parts. Sometimes what seems unfixable only takes 5 minutes!
Basic troubleshooting
These steps will help you track down 90% of your problems and will most likely fix 75% of them:
1. Before doing anything ALWAYS pull out all the socketed chips and clean them, as well as cleaning the sockets themselves (make sure you pay attention to the direction they were facing when you pull them out so you don’t put them back in backwards, some chips aren’t notched to help you with this). You can buy a chip puller and contact cleaning spray at any Radio Shack – This will save you A LOT of headaches.
2. Whenever possible put in a known good power supply.
3. Replace your fuses. Even though they may look good strange things happen to them after 20 years!!
4. Make sure you have 5v coming out of your power supply and through the board. Many boards have testing spots on the board to check, if it doesn’t then use a capacitor as it has a nice big lead to put your probes on (and remember the power is DC so if you reverse your + and – you won’t get a reading). This should narrow down a broken trace problem for you.
5. Hot stuff!! Check the heat on the chips on the board. If a chip is shorted it will noticeably heat up.
6. If something starts good then after awhile goes bad, get some freeze spray from Radio Shack. If something doesn’t go bad until it warms up then cool down components one at a time until you find the offending part.
7. For Gods sake – learn how to discharge your monitor!!! Don’t touch the red suction cup.
8. Carefully examine your board for scratches, broken traces, empty sockets (sometimes they are supposed to be empty though, check your manual), burns (sometimes burns aren’t as bad as you think though, ask any Pole Position owner about their edge connectors), and broken legs on capacitors.
9. Cap your monitor!
SPECIFIC ISSUES
Monitors:
Prob: My WG 4600 has sawtooth edges and/or squished images flying across the screen!
Sol: This is the problem I encountered on my Berzerk, I though for sure I’d need to install a cap kit – wrong! This particular monitor sometimes goes so far out of sync that the adjustment pots won’t work. Look for a small tin box with an adjustor on the daughtercard closest to the monitor yoke. Make sure you either pull the card out or use a plastic screwdriver and turn once or twice in one direction and then go the other direction if it doesn’t work that way. Keep trying and eventually it should clear up. Fine tune with the normal adjustment pot. I’m glad I didn’t go through the trouble of the cap kit as this monitor is beautiful without it.
Prob: My WG 4600 has a blue/red/green background, I can still see the graphics but they are washed out.
Sol: Replace the transistors in location 208-210 on the video input daughter card. I know T208 is blue but am unsure what the other colors correspond to.
PCBs
Prob: My MCR game won’t come up.
Sol: Disconnect the reset circuit (the famed purple wire in Tron). Check your games manual for the correct wire.
Prob: DK is missing some or all sounds.
Sol: Everyone thinks that the monitor sound card is the source for all these problems, not true. Check the area surrounding C22 on your board. There’s a bunch of small blue caps here that may not all be working right. If any of these get broken (look for cold solder joints as well) your sound won’t work correctly.
Prob: My Pole Position comes up into test mode and says all ROMs and RAMs are ok but a portion of my screen is missing and it won’t boot into the game.
Sol: Check your processors. You will most likely find a bad connection on one of the Z80s.
Prob: Berzerk won’t go past the 4th beep
Sol: Check the dip switch settings on your video board. Berzerk has a switch to set for either Electrohome or WG monitors and on mine it wouldn’t come up until this was set properly.
Prob: Some of my vectors are missing!
Sol: Turn up your brightness all the way and see if they appear. If not then check the voltage levels of your HV unit – don’t assume your problem is on the game PCB.
Prob: How do I get the monitor of my Donkey Kong (or Jr. or DK3) to not invert the video output?
Sol: Look at photo "A" on the bottom of page, it's easier to show you how than to tell you. There are two male plugs, switch that cable to the plug that I'm pointing at in the picture.
Photo "A" - DK inverter board, move the cable right next to my finger to the plug I'm pointing at. The picture is looking down on the right side of the monitor (as you see it from the back).
