is my rectifier bad???

66 joe

Petty Officer 2nd Class
Joined
Aug 9, 2008
Messages
128
its for a 112 johnon spl; reading some links and following oem manual, i've got measurable resistance between ground to yel, yel/gry and red 1 way,,, but (next step) red to yel/gry (res one way) then red to yel- open,,, no resistance. Power head is being rebuilt, and 2 years ago I noticed charging system was not working,, I think my error of running motor w/o battery for few mins. Just thought I'd double check w/ experts,,, thanks, Joe
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: is my rectifier bad???

Sounds like it is shot.

There are 8 tests to make:

R to Y
R to Y with meter leads reversed

Should show high resistance on one and low resistance on the other of the two above two tests.

Repeat with
R to Y/G
R to Y/G (reversed)
Ground to Y
Ground to Y (reversed)
Ground to Y/G
Ground to Y/G (reversed)

If any of the 8 fail, it is shot.
EDIT: The tests won't work with many of the digital multimeters. But it will work with an el-cheapo analog meter. Go figure.
 

66 joe

Petty Officer 2nd Class
Joined
Aug 9, 2008
Messages
128
Re: is my rectifier bad???

Thank you,, thats what I thought. And Im glad to here its bad considering theyre not too expensive and easy to replace. Joe
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,720
Re: is my rectifier bad???

EDIT: The tests won't work with many of the digital multimeters. But it will work with an el-cheapo analog meter. Go figure

I figure it is becase the digital meters only apply a very small voltage when testing on the ohms ranges. The diodes in the rectifiers need in excess of around 0.7 volts to make then conduct. If less is applied you get a high reistance reading both ways.
(one day I'll check my theory)

Diode test range works, as you would expect.
 

66 joe

Petty Officer 2nd Class
Joined
Aug 9, 2008
Messages
128
Re: is my rectifier bad???

the meter i used is a analog ohm meter and not a very cheap one. so hopefully, replace rectifier and battery will start charging again, and i'll never ever disconnect battery w/ running motor
 
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