Rectifier/regulator check

[mrsoup]

My 83 has toasted a stator and maybe the R/R too. I have read the Haynes manual and the factory service manual on how to check these items but I cannot seem to get good readings on the R/R. How does my multi-meter need to be set to check diodes in the R/R? The page I copied that explains all the tests for motorcycle electrical systems mentions 10X for the ohm reading but I am not sure how to do this with my Blue Point or Radio Shack meters. Can someone steer me in the right direction? I understand that diodes only let things flow one direction but how do I check them?

[Dave T.]

Some multimeters have a diode check setting next to the lowest ohm scale. For diode check, the multimeter puts 3V (or 1.5V from the dry cell in the meter) through the diode, and if it conducts, the voltage will drop to around .6 volts and beeps once (my fluke meter does anyway). The stripe around a diode end is the cathode side (negative) and the other lead is the anode (+). If you forward bias the diode it should conduct current. If you reverse the multimeter leads, red on the cathode side, black on anode side and test it, it shouldn't conduct (no voltage drop, OL).

 As far as using the ohm scale for testing, use the smallest scale you have, like 0-200 ohms. Most have many scales, like 0-2k ohms, 0-20k, 0-200k up to 2Mega ohms and beyond. Mega ohm meters go into the billions of ohms.

The thing is that your ohm meter uses voltage to check ohms. I am not quite sure of the circuit, such as voltage drop across an internal resistor would be my guess. But the testing voltage should be enough to make the diode conduct when positively biased. And the diode should block current flow when negatively biased, hense reversing the meter probes. Just go between 3 white R/R leads and the red output wire to test the first three diodes and go between the 3 whites and the black (ground) to test the other 3 diodes (6 in all) There should be 12 tests total. ?Current should flow in one direction (+ to -) and be blocked in the other (- to + or black to red). If current flows (low ohms) in both directions, the diode is shorted. If current flows in neither direction (OL on LED ohmeters), the diode is open.

As far as testing the regulator, I am not sure how to do this, you would have to have a voltage source between 10 and 20 volts and see if output stays below 14.5 volts. Also you would probably need an oscilloscope to test the SCR and zenier diode.

Have fun! ? :P

[Cdnlouie]

I just did a check on my vision this week as my stator is also cooked.  I have not had this confirmed but the Haynes manuel seems to have the leads (positive versus negative) reversed in the explanation. I may be doing something wrong but I get the proper readings according to Haynes with my radio shack ohmmeter but with the opposite leads attached.  I will know shortly as soon as my stator arrives.

[Cdnlouie]

I would love to have this point confirmed about the Haynes manual being incorrect on the R/R check.  Here is my current test results of a R/R which I do not know if it is functional or not as I am waiting on a stator which was definitely bad.  Keep this in mind.

I am using the diode test.  Placing the positive multimeter lead on the red R/R wiring harness and the negative multi lead on each white stator harness wire I get ?0L? or no voltage continuity on all three.  Reversing the multi leads (negative multi lead to red R/R wiring harness) and touching the positive multi lead to each white stator wire I get .51 volts continuity.

Now placing the positive multi lead on the Black R/R wiring harness and the negative multi lead on each stator harness wire I get .51volts continuity.  Reversing the multi leads (negative multi lead on Black R/R wiring harness) and touching the positive multi lead to each white stator wire I get ?0L? or no voltage continuity.

So anyone care to cast their vote to confirm this test as accurate and indicating the likelihood of this Rectifier/Regulator having achieved at least a bench test pass.

[George R. Young]

About the polarity of ohmeter readings:

The battery in the meter is installed arbitrarily, depending on the make of the meter.

As long as a diode reads low resistance in one direction and high in the other, it's good.

[Lucky]

i'm in the hospital right now with pnumonia , so i haven't been here since fri, and won't be out for a few more days

I may be wrong about this, but the diode check of a reg/rec in my V that wasn't charging was "reversed",  according to the electrex chart, that's the only part of the charging system that had failed. (i had previously replaced the stator with the electrex part, but failed to retest after that, shame on me!)

anyway, i swapped out the reg/rec with a known good one, and everything has been fine since.  i don't know why the polarity was backwards, and why the bike wouldn't charge this way... but replacing it worked....  one day i'll sit down and study the situation.

--Lucky

[Cdnlouie]

To Lucky et al,

My stator arrived this week and the conclusion of whether we have a good regulator/rectifier is now in.  It is an OEM R/R and according to the Haynes and Electrex fault finding charts, it would have failed and been chucked.  The test I stated previously in this post is opposite (in the sense of you need to reverse the leads) in the Haynes and not even close to the Electrex readings. They both led me to believe my R/R was toast.  Electrex is the most confusing since they give four totally inapplicable readings and when my R/R tested 0 volts as described above, I would have assumed I had a faulty regulator.

Those who voted "Yes" get the kudos as, the R/R performs totally up to specs after 100km of running.  Charges at good solid 14.45 at idle and about 13.98 at higher rpms.

Thanks to the guys here who gave some good information that also greatly helped me think this one through.

About the battery polarity reversal comment, at least on my digital Radio Shack meter, it is not possible to reverse the batteries or it just does not work.

The moral of the story: None of the pro sources seem to really know what their talking about with R/R's, at least not the XZ550. I hope they prove me wrong soon. :P

[Lucky]

Hi Louie, just an observation, and i'm sorry it wasn't sooner...
I re-read your post above on testing your r/r, and as a mater of fact, you followed the Electrex chart accuratly. ?

according to the chart the r/r fails 2 of the four tests.

Here's the thing, even though your charging well, i'd replace the r/r, or at least see if you can test a known good one and compair the results. ?

I have seen a patern here of stators being replaced and later on down the road, having the "new" stator burn out, along with the r/r. ?

here's what happens:
the bike fails to start,
stator is checked, confirmed bad & replaced.
bike charges well (even if r/r fails testing)
stator fails again and is replaced with r/r
no more problems.

too many people here think that just because the system is CHARGING well that indicates it is OPERATING properly. ?they are not the same thing. ?you can have a faulty r/r and still put out 14.5V. ?

On my bike the fact that my polarity's were reversed DID indicate a problem, even thought it "sounds stupid", backwards is still incorrect. ?swaping the part DID cure the problem.

--Lucky

[Cdnlouie]

Thanks for the heads up Lucky.  I was hoping someone would comment on the situation of a R/R still charging, but with the potential to burn out a new stator.  It would be great to collect some more statistics on this phenomenon.

If this is true, and I believe your observations carry some weight, the R/R could be the first item to deteriorate on a Vision charging system taking out the stator in due process of time.

I would like to suggest that Vision riders perform the electrex test on their bikes as a preventative measure, even though they are still charging and see what results come in.  If some guys have similar situations to your previous experience and mine, yet are still charging, this may save themselves a stator by replacing the R/R first.

One observation I would like to make about the R/R is the fact that it depends upon cooling to dissipate the extra voltage generated by the stator at higher rpms.  It could not be mounted in a hotter location than behind the rear cyclinder exhaust and what amounts to pretty much a closed space.

Just some more thoughts,

Louie