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Issue with SA-7800

So here is what I believe is the path from d30 cathode to fu3.... i dont see any other points to check? Did I go the right path?

ohmsreading.jpg
 
Set your DMM on lower ohm. One test probe on 40 test point and the second on diode. A lower indicatiin or zero means your circuit is closed - good. If it is indicate 1 then your circuit is open - bad. Chech fuse in same way.
 
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that board is same as one mark talks about ..
ok lets try this ... test on soldered side to see if continuity exists between d30 and the fuse 3 .. then same again top of the board if soldered side checks out good .
 
petehall347 said:
that board is same as one mark talks about ..
ok lets try this ... test on soldered side to see if continuity exists between d30 and the fuse 3 .. then same again top of the board if soldered side checks out good .
Click to expand...
I get .01 on both sides with the continuity test between d30 cathode and fu3
 
paul_ral said:
Set your DMM on lower ohm. One test probe on 40 test point and the second on diode. A lower indicatiin or zero means your circuit is closed - good. If it is indicate 1 then your circuit is open - bad. Chech fuse in same way.
Click to expand...
On the ohms test how you stated... i get 1.3 on the point 40... and 0.7 when on the fuse itself
 
logically there should be loss of continuity as the AC voltage is not present at d30 ... but there isnt so that voltage should be there ..
2 things i can think of ..
1 .. human error ..
2... poor connection that loses continuity with power applied .
remove the solder from d30 and use some fresh solder on it .
 
That's good. If your transformer is good, fuses are good too you should have voltages on d27 and d30.
 
Or a faulty... MM.... I just picked up the MM to do another reading and the positive probe came off its wire... i'm going to have to get a new Multi Meter... ugh
mmbroke.jpg
 
I wanted to show this picture again showing the 4 diodes... the 2 on the left (which include d30 and d29) the cathode side is at the top, whereas with d27 & d28... the cathode side is at the bottom... is that okay and any reason why the reading would be off?
20180801_203245.jpg
 
Ryan Walton said:
Okay so here are the correct AC readings for the diodes now that i know where they are:

D27 (cathode) - 141.5
D27 (anode) - 47.3
D28 (cathode) - 141.8
D28 (anode) - 47.3
D29 (cathode) - 47.4
D29 (anode) - 0.00
D30 (cathode) - 47.3
D30 (anode) - 0.00 and -0.00 (fluctuates between the 2)
Click to expand...

This is what i put earlier.
 
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