(Topic ID: 264167)
Massillon, OH
Marco shows in stock https://www.marcospecialties.com/pinball-parts/5012-09429-00
That resistor is part of the current sensing circuit so you need to remain in the 0.12 ohm range.
Yeah, just checked my RC5W-0.12 resistor stock - shows nothing left.
The resistor looks good in photo, how are you sure it is bad. These don't fail often.
But - is that 330uF electrolytic cap leaking?
Last photo - parts look pretty decent physically aside from some small cosmetic stuff. Is there a problem with this board?
Don't bugger with the two power transistors on the heat sinks unless you have to, those are hard to get.
Did you check that 330uF electrolytic cap? Doesn't show up in this photo. Based on the looks of this board in this last photo, that could be just solder flux near the cap but should be checked anyways.
Quoted from G-P-E:Last photo - parts look pretty decent physically aside from some small cosmetic stuff. Is there a problem with this board?
Don't bugger with the two power transistors on the heat sinks unless you have to, those are hard to get.
Did you check that 330uF electrolytic cap? Doesn't show up in this photo. Based on the looks of this board in this last photo, that could be just solder flux near the cap but should be checked anyways.
Not getting proper voltage at my 5volt pins. I'm getting 100 and -100
Screenshot_20200315-183702_Chrome (resized).jpgOK -- with the exception of the 0.12 ohm current sensing resistor (R13), the section you are taking pictures of is your +100 and -100 Volt section.
If you are really getting 13.9V at the 5V connection - do NOT hook up any other boards until you get this ironed out.
Very first thing I would look at is your voltage at TP3 coming in and make sure it is not too high.
Still doubtful the 0.12 ohm resistor has anything to do with your problem.
Did you replace C7 and C8? The voltage doubler section will cause the 723 voltage regulator to act up. This section is pretty frail if C7 and C8 are getting old. Check voltage at IC1, pin 12 - what voltage do you get there.
Time to measure voltages around Q5.
Collector - going into Q5 should be same as TP3.
Emitter = output voltage, should be about 5V.
Base = controller for transistor Q5, should be a hair above your output voltage of 5V.
Quoted from G-P-E:OK -- with the exception of the 0.12 ohm current sensing resistor (R13), the section you are taking pictures of is your +100 and -100 Volt section.
If you are really getting 13.9V at the 5V connection - do NOT hook up any other boards until you get this ironed out.
Very first thing I would look at is your voltage at TP3 coming in and make sure it is not too high.
Still doubtful the 0.12 ohm resistor has anything to do with your problem.
Did you replace C7 and C8? The voltage doubler section will cause the 723 voltage regulator to act up. This section is pretty frail if C7 and C8 are getting old. Check voltage at IC1, pin 12 - what voltage do you get there.
Time to measure voltages around Q5.
Collector - going into Q5 should be same as TP3.
Emitter = output voltage, should be about 5V.
Base = controller for transistor Q5, should be a hair above your output voltage of 5V.
Yes, other caps have been replaced.
UA723cn has some corrosion on it. I have an order coming your way, I'll have to add this chip. Could that cause a problem with my 5v?
Thanks again
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