L275 alternator not charging. Diagnose & overhaul questions

[timsch]

Which blasting gun do you have? (I assume you're satisfied with it). FRom my search, it looks like there are plenty of junk ones out there....

My Fluke 177 meter does have a diode test selection. I'm trying to understand your directions to test the diodes individually. I am testing just as is shown in fig.79 above, which shows a probe on one of the three pairs of stator mounting terminals. I'm doing this for all three pairs and then switching the probes as it states and do that three more times. I'm getting diode readings for each around 0.53VDc. Odd thing is, I get the reverse readings from what's directed in that figure, which is that it is my negative probe on the M6 stud and positive on the terminal which gives me the 0.53 reading, and infinity when the probes are switched. Same for all three pairs. If this is a failure, it's the oddest failure I've run across.

 

[Hugo Habicht]

Not sure, but I do remember, about 200 years ago, that analogue meters (like in figure 79) have the polarity reversed when using the Ohm ranges (so plus comong out of the minus terminal). Could be wrong though.

If you have another meter just measure the output polarity from your Fluke. The digital meters I have show the diode voltage with the plus terminal to the anode and the minus terminal to the cathode.

So you should see the voltage when plus of the meter is connected to the stator terminals and minus of the meter to the battery plus stud for example. The other way around with the stator terminals and the battery minus stud.

If all diodes show the wrong way round then your meter has simply the output polarity the other way round, nothing to worry about. A diode goes open or short (and some other failure modes that we will not discuss here for simplicity) and it definitely did not happen that a diode changed its polarity, let alone 6 of them

Did you find any contact problems on the rectifier?

If not your charging problem must be the rotor winding, the brushes or the voltage regulator itself.

 

[Hugo Habicht]

The soda blasting gun I have is in the picture. The company is BGS, but they are only branding other companies stuff, so a fairly safe bet is that it is from China.

The reservoir on top is not huge, but for cleaning carburettors or those alternator parts its fine. I am sure there are better ones out there but for the few times I use it it is value for money.

 

[bird dogger]

I use a "Speed Blaster" brand spot blaster for doing some soda blasting of small parts.

Check my Soda Blast kit pics and what I use for a cheap source of soda blast media.

 

[lmichael]

The soda blasting gun I have is in the picture. The company is BGS, but they are only branding other companies stuff, so a fairly safe bet is that it is from China.

The reservoir on top is not huge, but for cleaning carburettors or those alternator parts its fine. I am sure there are better ones out there but for the few times I use it it is value for money.

I have the same one but got it from Harbor Freight (or as some call it) Hazard Fraught. Even my large compressor cannot keep up with it. Maybe because of what I tried to use in it (some kind of ground glass or something they sell for it). IDK but the experience was NOT pleasant

 

[willyeckerslike24]

Not sure, but I do remember, about 200 years ago, that analogue meters (like in figure 79) have the polarity reversed when using the Ohm ranges (so plus comong out of the minus terminal). Could be wrong though.

If you have another meter just measure the output polarity from your Fluke. The digital meters I have show the diode voltage with the plus terminal to the anode and the minus terminal to the cathode.

So you should see the voltage when plus of the meter is connected to the stator terminals and minus of the meter to the battery plus stud for example. The other way around with the stator terminals and the battery minus stud.

If all diodes show the wrong way round then your meter has simply the output polarity the other way round, nothing to worry about. A diode goes open or short (and some other failure modes that we will not discuss here for simplicity) and it definitely did not happen that a diode changed its polarity water gun party rentals, let alone 6 of them

Did you find any contact problems on the rectifier?

If not your charging problem must be the rotor winding, the brushes or the voltage regulator itself.

Yes, The soda blasting gun shown in the picture is branded by BGS; however, BGS typically rebrands equipment manufactured by other companies.