Arcade Collecting > Restorations & repair
Asteroids Deluxe resurrection
ChadTower:
Okay, I've been backed off and regrouping a gameplan:
For the WG monitor's green issue: On Randy Fromm's WG7000 troubleshooting flowchart, a green only issue points to these two transistors: Q2 and Q202. I found them on the schematic. One is on the neckboard by the green potentiometers, the other is on the upper right corner of the chassis PCB. I'm going to desolder both of those and test them with the DMM. These are both cheap parts and can be had at Radio Shack.
For the AD board: Discussion with the folks at RGVAC leads me to the DAC and OP Amp in the X section of the video circuit. That's the first and most likely place to check. I have replacement chips on hand from Bob Roberts, but the DACs are $11 each so I don't want to blindly replace them. I've also ordered some SIP sockets so I can desolder the questionable chips and solder in some quality sockets. This will allow me to move them around in appropriate spots so I can observe voltages and figure out which, if only one, is actually bad, while replacing the minimum number of expensive chips. I'm also going to check/clean/rebend if necessary the pins on the PCB edge harness, as well as retinning the edge contacts. I'm actually going to do this first just in case a problem here is causing it to act like the board has problems.
For the AD monitor: Once I think I have the game board in a better working state, I'm going to recap the monitor. I have the cap kit in hand.
For the AD cab: I have a replacement big blue PS cap and will be replacing this as well.
That's my plan going forward, should take me some time to get all of this done since I'm still pretty slow at this stuff. Advice/criticisms/suggestions are welcomed.
fredster:
Hi Chad,
Good Idea, don't get burned out.
Answer to this question: How do you test a potentiometer? - Put a clip/test probe on the prong in the middle and one of the sides. Take your ohm meter and set it to any range at first, then move the knob. The meter moves. All the way to 0 to whatever. But it should move.
If you aren't happy with your soldering, remember 1/2 of it is in the solder. Get some .032 60/40 solder and maybe even some .015 60/40. You have the magnifiying glass. Find a board and practice some more. Do a few chips before you go for the AD board.
I say don't worry about the "expensive" chips. Put in the sockets where they belong and just put them in, one at a time. You are in training. Once you get this done it's worth more working and as an assembly than it is dead like that. Tacky but true - you can't make an omlete without breaking a few eggs.
Green on one of those monitors can mean that the tube is bad. Remember the grid cleaning trick Randy has, you can try that too.
I might suggest that if you want to work on wiring harnesses that you buy bob's little tool he uses. I have one of those and I can pull out any molex/wire from my harness in about 0.4 seconds and put it back unscathed. It's a snap if you have the right tools. It's what separates us from the animals.
ChadTower:
Yeah, I'm going to need a set of molex tools anyway, given that I have two pins here that are also in the queue to be fixed.
SirPeale:
I actually ended up getting my Molex extractor from Rat-Shack. I think it was ~$7.00. Works *very* well, but took some getting used to to make it work.
ChadTower:
Dammit. I'm having trouble locating one of those monitor transistors locally and am sick and tired of paying shipping on tiny parts.
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