Diode check on PMA regulator rectifier High Voltage

[bpupeza]

I am getting up to 18 volts at the battery when I rev the engine. I have the xscharge PMA along with the regulator rectifier made specifically for it. I disconnected the R/R and did a diode check. I have never done this before. When I put the positive lead from the meter to the positive wire on the R/R I get a reading of 1. Negative to negative gives me the same result. When I put the positive lead from the meter to negative on the R/R I get readings to all of the yellow wires around 500! I get the same results with the negative lead of the meter to the positive wire on the R/R.
I was under the understanding that the reading should be closer to .500 not 500.
Has anybody else ever done a diode check on their xscharge regulator rectifier? What were your readings.
Thanks for any input.

 

[XSLeo]

I don't think the rectifier part of your reg/rec is the problem. Usually if a diode goes bad the out put voltage drops. This happens because it affectively removes one leg of the stator output from the circuit.
A high voltage is a reg issue.
On just a rectifier as the stock system uses. If you hook the red lead of your meter to the positive wire on the rec, touch the black lead to the yellow wire you will get one reading. Either a high reading or a near zero reading.
Reverse the meter leads and you should get an opposite reading. One way a high reading the other low.
Now hook the red lead to the negative wire on the rec, touch the black lead to the yellow wires. Reverse the leads.
This will give you another sets of readings. One high, one low. These reading should be opposite from the first set. If so the diodes are good.
Doing this test on the stock reg/rec works because you are testing just the diodes, the reg part is separate.
Now on a PMA reg/rec with the reg in there somewhere I'm not sure how that will effect your readings.
Going from what you said your readings are the rectifier part is ok.
When you did those checks, what position did you have your meter in? Ohms or the Diode check? Some meters have a diode check position. In this position it sends a voltage to the diode and reads how much voltage drop there is across the diode. Again one reading should be low the other high.
If so your rectifier is ok.
Now on the regulator side I don't know of any way to test that part, Except swapping in a known good part.
Is this high voltage just after your initial install or has it been running awhile and this issue just came up?
If on a fresh install it may be something like a poor ground.
Check to see that the body of the reg/rec has good clean bare metal to clean bare metal contact to the frame or a good ground wire from body to battery negative.
Leo

 

[bpupeza]

I don't think the rectifier part of your reg/rec is the problem. Usually if a diode goes bad the out put voltage drops. This happens because it affectively removes one leg of the stator output from the circuit.
A high voltage is a reg issue.
On just a rectifier as the stock system uses. If you hook the red lead of your meter to the positive wire on the rec, touch the black lead to the yellow wire you will get one reading. Either a high reading or a near zero reading.
Reverse the meter leads and you should get an opposite reading. One way a high reading the other low.
Now hook the red lead to the negative wire on the rec, touch the black lead to the yellow wires. Reverse the leads.
This will give you another sets of readings. One high, one low. These reading should be opposite from the first set. If so the diodes are good.
Doing this test on the stock reg/rec works because you are testing just the diodes, the reg part is separate.
Now on a PMA reg/rec with the reg in there somewhere I'm not sure how that will effect your readings.
Going from what you said your readings are the rectifier part is ok.
When you did those checks, what position did you have your meter in? Ohms or the Diode check? Some meters have a diode check position. In this position it sends a voltage to the diode and reads how much voltage drop there is across the diode. Again one reading should be low the other high.
If so your rectifier is ok.
Now on the regulator side I don't know of any way to test that part, Except swapping in a known good part.
Is this high voltage just after your initial install or has it been running awhile and this issue just came up?
If on a fresh install it may be something like a poor ground.
Check to see that the body of the reg/rec has good clean bare metal to clean bare metal contact to the frame or a good ground wire from body to battery negative.
Leo

Thanks for you reply.
I was using the diode check setting on my meter.
I have had this bike as an ongoing project for quite some time. I did not just recently install the PMA. I do not recall for certain if I checked the voltage at higher RPM when I first installed it but I have to believe that I would have.
I have the green wire which is ground bolted to the frame. You mentioned that the body of the regulator/rectifier needs to be grounded as well. I had it mounted to the stock battery box which is rubber mounted.
The original reason that I started checking things out is because I just installed a new set of VM 34 carbs and some new mufflers. It runs nicely if I am easy on the throttle but if I am cruising along in third or fourth gear and I crack the throttle hard the bike falls on its face.

 

[XSLeo]

That sounds like carb tuning as far as that goes. I doubt that has anything to do with your charging issue.
The high voltage is another problem. That much can damage other parts of your electrical system.
Is that voltage with or without the headlight?
You may need to add lighting with more current draw to use up some of the extra power. A lot of PMA reg/rec's won't do the job well unless there is some load on the system. Don't run LED's for anything. Use regular bulbs. These will draw more current from the system and help bring down the voltage.
Leo

 

[gggGary]

Chinese regulator built to a price not a standard, what could go wrong? Oops you have that answer.

 

[bpupeza]

That sounds like carb tuning as far as that goes. I doubt that has anything to do with your charging issue.
The high voltage is another problem. That much can damage other parts of your electrical system.
Is that voltage with or without the headlight?
You may need to add lighting with more current draw to use up some of the extra power. A lot of PMA reg/rec's won't do the job well unless there is some load on the system. Don't run LED's for anything. Use regular bulbs. These will draw more current from the system and help bring down the voltage.
Leo

I did it with and without the headlight on. I turned on a signal but it was still high.
I have the pamco with electronic advance so I was just making a basic check of the battery and the regulator rectifier and I was going to move on to timing from there. I have all of the stock lighting except for the flasher unit. My bike is a 73 but I have a later engine in it.

 

[gggGary]

DO NOT run that pamco with 18 volts in the system, you will let all the smoke out.

 

[bpupeza]

Chinese regulator built to a price not a standard, what could go wrong? Oops you have that answer.

On the surface that's what it looks like to me. I just didn't want to start throwing parts at it if there was something more basic that I was missing up front. I have no idea where this part is made. I am not sure if there is a Japanese equivalent.

 

[bpupeza]

DO NOT run that pamco with 18 volts in the system, you will let all the smoke out.

Yeah and then you cant get it back in let alone even find the smoke once it escapes.

 

[XSLeo]

I seem to remember there are two different types of reg/rec's for PMA's. The regular ones most come with that are fairly inexpensive. Then there is one that costs a lot more. It has a MOSFET in it that better controls the voltage.
May want to search on here for that.
Leo