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#21 | |
Badcaps Veteran
Join Date: Jun 2012
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![]() Quote:
If you are not getting any a/c to the bridge, check the resistance of the traces and the power supply winding that supplies that circuit. What is the part number on SR3? |
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#22 | |
Member
Join Date: Feb 2010
City & State: Ames Iowa USA
Line Voltage: 120VAC 60Hz
Posts: 69
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#23 |
Badcaps Veteran
Join Date: Jul 2011
City & State: Some times Sunny Jacksonville FL
My Country: USA
Line Voltage: 120 Volts 60 HZ
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![]() If this machine has a step down transformer that supply’s power to this board look and see if it says 110 volt or not because if does do you know if your facility has a hot leg if it does then you might have the transformer on the wrong set of legs because if the step down transformer says 110 to 120 volts output
Because I has this happen to me one time and when I switch the legs to a certain way I got the correct voltage however do not change the machine main power supply legs unless you do NOT have any other motors on this machine because your rotation might be wrong
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#24 | |
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#25 |
Member
Join Date: Feb 2010
City & State: Ames Iowa USA
Line Voltage: 120VAC 60Hz
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![]() Yes, it does. I measured half an ohm (0.5 ohms) resistance on the traces. The letters and numbers on the apparent BR are LBA 63.
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#26 |
Badcaps Veteran
Join Date: Jun 2012
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![]() I suspect you have the -15 volts, It was only missing because the main transformer was not being used.
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#27 |
Member
Join Date: Feb 2010
City & State: Ames Iowa USA
Line Voltage: 120VAC 60Hz
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#28 |
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Join Date: Feb 2010
City & State: Ames Iowa USA
Line Voltage: 120VAC 60Hz
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#29 |
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![]() That proves the bridge rectifier and the rest of the -15v circuit is ok. The fault is then with either the transformer not supplying the a/c to the bridge or there is a break (or small fuse) between the transformer and the bridge rectifier.
I hope the transformer was NOT connected when you applied the 20 volts to the bridge? if it was that may have opened the winding on the transformer as the winding would be a very low resistance to the 20vdc. Last edited by R_J; 11-17-2021 at 06:48 PM.. |
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#30 |
Member
Join Date: Feb 2010
City & State: Ames Iowa USA
Line Voltage: 120VAC 60Hz
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![]() Well, I found the problem causing no -15V. It's the connector. It's not making good contact, but I'm sure I accidentally bent that pin when I was originally trying to measure transformer output voltages. So I'll have to either fix that or replace the connector. I've seen this type before so I assume I can find one.
So now I guess I power it up on 120V with attention to that connector and see what I get. |
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#31 |
Badcaps Veteran
Join Date: Jul 2011
City & State: Some times Sunny Jacksonville FL
My Country: USA
Line Voltage: 120 Volts 60 HZ
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Posts: 3,582
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![]() Let us know if you were able to fix this board issue or not
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