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(Topic ID: 137708)

Kiss Rectifier Board (as-2518-49)


By troxel

5 years ago



Topic Stats

  • 11 posts
  • 5 Pinsiders participating
  • Latest reply 2 years ago by wizard_mode
  • Topic is favorited by 1 Pinsider

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#1 5 years ago

Rebuilt the rectifier board on my Kiss and tried testing it on the bench (with no load) and got the following results:

TP1 =3.5V
TP2 = 95V
TP3 = 11.3V
TP4 = 3.9Vac
TP5 = 32.1V

All the voltages seem low, but have tested every component and all tested good. Any suggestions?

#2 5 years ago

It is worth checking that the transformer tap is set for 110/120v.

That is a fairly normal reading when unloaded. I would expect a couple of them to be higher with the resistors built onto the rectifier board. As long as you get in the ballpark voltage reading and the fuses don't blow, you are safe to test under load.

#3 5 years ago

Perhaps you are not getting a good ground for your meter lead. Try using the bottom lead of the large resistor on the right side of the board.

Check the AC input voltages on each of the bridge rectifiers which should match the schematic.

#4 5 years ago
Quoted from barakandl:

It is worth checking that the transformer tap is set for 110/120v.

That is the first thing I would look at. Assuming those are true voltage readings, they`re not even close to where they should be. Even unloaded. Usually the reading will be higher without load. Those readings are way low.

TP3 is the only one which is correct, which is weird. If the mains are connected to the wrong winding on the transformer, all of the readings should be out by the same ratio.

Also ensure that your voltmeter batteries are good and you`re getting good measurements

#6 5 years ago
Quoted from Lindsey:

That is the first thing I would look at. Assuming those are true voltage readings, they`re not even close to where they should be. Even unloaded. Usually the reading will be higher without load. Those readings are way low.
TP3 is the only one which is correct, which is weird. If the mains are connected to the wrong winding on the transformer, all of the readings should be out by the same ratio.
Also ensure that your voltmeter batteries are good and you`re getting good measurements

Lower end DMMs have trouble reading a circuit with no load. Hard to say.... In my experience a bally game everything reads high unloaded except for the 230v for the display reads way low.

#7 5 years ago

Got it working.

Hate to say it, but user error. I was going off the photos I took before I disconnected it, and switched the two red wires around. Once I looked at the schematics, I can tell that it was incorrect. Thanks for pointing me in the right direction!

#8 5 years ago
Quoted from barakandl:

Lower end DMMs have trouble reading a circuit with no load.

That`s not really going to be an issue with linear power supplies in a pinball machine. Even the crappiest meter should still get you in the ballpark.

If your meter is giving you those kinds of reading from a known good rectifier board, its time to throw that meter in garbage

There`s an example of checking the rectifier board test points in this video at 4:30.

#9 5 years ago
Quoted from Lindsey:

That`s not really going to be an issue with linear power supplies in a pinball machine. Even the crappiest meter should still get you in the ballpark.
If your meter is giving you those kinds of reading from a known good rectifier board, its time to throw that meter in garbage
There`s an example of checking the rectifier board test points in this video at 4:30.
ยป YouTube video

What ballgame we playing. Check with a fluke. I can guarantee the high voltage will read like 60v too low. That is 30% off. The only ones you can trust is the dc voltages with the load resistors. Check with a cheap meter, and it gets even further off.

#10 5 years ago
Quoted from barakandl:

What ballgame we playing. Check with a fluke. I can guarantee the high voltage will read like 60v too low. That is 30% off. The only ones you can trust is the dc voltages with the load resistors. Check with a cheap meter, and it gets even further off.

You're definitely right about the HV. I always thought that was weird when I first started working on Bally stuff.

If only the high voltage was showing a weird number then you would have a point. That was not the case, so the quality of the meter isn't really relevant. Like I said, the crappiest meter will get you in the ballpark of what are known to be good voltages for this board without load. Even the high voltage. The voltages posted are not even close, so which meter you're using isn't relevant. Unless its totally boned, which I already mentioned.

The point is that the voltages produced by an unloaded Bally rectifier board are well known and even the shittiest meter would not be off as far as what the OP reported.

I don't think anyone is denying that the HV reads weird unloaded. But the weirdness is consistent and predictable.

EDIT: To be clear, when I said "If your meter is giving you those kinds of readings with a known good rectifier" I was referring to the readings posted by the OP. I'll stand by that. If a Fluke is giving you normal readings and another meter with good batteries is giving you THOSE readings then your meter is broken.

2 years later
#11 2 years ago
Quoted from barakandl:

Lower end DMMs have trouble reading a circuit with no load. Hard to say.... In my experience a bally game everything reads high unloaded except for the 230v for the display reads way low.

Any idea why the 230VDC reads low? I rebuild my Harlem Globe Trotter Rectifier board with new header pins, bridge rectifiers, and diodes. When powering on my bench, all voltages check good EXCEPT the 230VDC which reads between 150-170VDC. The AC in is good (120VAC) as is the 173VAC into the 230VDC rectifier circuit (4 diodes and a resistor). One thing I noticed is the resistor R3 on my recitifier board is an 80kohm whereas the schematic calls for a 100kohm. I left the 80 on there thinking that replacing it with a 100kohm would lower the voltage even further!

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