Arcade Collecting > Restorations & repair
Star Wars - fully working!
Level42:
See, you DO have a AC/DC select button ! It's right there in the middle under the display....right over the "Craftsman" logo.
It also doubles as a select button between real Ohms (resistance) measuring and "diode-tester/continuity measuring.
Now write 100x:
I shall read the manual before using any equipment.
:laugh:
http://www.metersupport.com/manuals/82175.pdf
Man, look at this, there's an interactive on-line tutorial of how to use it......even Fluke doesn't have that:
http://www.metersupport.com/virtualDemos/82175vd.html
Nice !
It also looks like the inputs are covered depending on your selection of voltage or amps measuring. Very nice, this way you can't hook it up wrong. (And blow your meter's fuse). Good feature !
Spyridon:
;D I was just testing you guys!
Okay, I feel a little stupid. I just wasn't used to the selector not being on the dial.
So, now that we figured that out...the readings above were done with DC.\
Level42:
--- Quote from: Spyridon on July 08, 2009, 08:10:35 pm ---Okay, I feel a little stupid.
--- End quote ---
You should ! ;) ;) ;) ;) Hey, "We're only human after all" :D
--- Quote from: Spyridon on July 08, 2009, 08:10:35 pm ---So, now that we figured that out...the readings above were done with DC.\
--- End quote ---
Which normally meant you'd have to do them all again....but in this case, you measured in DC and get steady values at pins that normally should have AC values. This shows that there's a good posibility that 9B/C is defective. I'm not saying 100%, but it is very likely.
Some background info you may forget right away, but I'm (poorly) trying to explain why I think 9B/C is bad:
The reason why I think so is that your readings are comparable between the X and the Y stages up to (and including) pin 5 of IC 9B/C and 8 B/C. From there, things start to differ between them.
Pin 5 is the positive input of one of the op-amps in that IC. Pin 7 is the output and that's the first point where you have a different reading (stuck high it seems). Pin 6 is the negative input of the op-amp and it's also stuck high but a little lower because that input 6 is used as a feedback from the output 7 through resistor R73.
Spyridon:
--- Quote from: Spyridon on June 30, 2009, 07:14:15 pm ---
As you can see, there are definitely some outliers on 9 B/C.
--- End quote ---
Just an update on this. I have a guy replacing this chip for me. He said that it literally crumbled to pieces as he was desoldering it from the board. That was some of the best news I've heard! Hopefully this was the problem and I can get this working again. Will have the board back in a couple of days.
Level42:
Seeing your great skills on restoring cabs Spryri, I think you would be more than able to do solderings yourself :)
Would save a lot of time. Also remember that that IC can have gone bad because some other part on the board being defective. Not trying to worry you unnesseraly but don't get your hopes up too high. Part replacing can be a lot of trial and error.
Crumbling sounds like the IC _was_ bad though :) Cooked itself....
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