700B blew one Right channel 5A supply fuse

laatsch55

laatsch55

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Ok, not important right now. Is the shorted 410 on the right channel? and is it just the one?
 
62vauxhall

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jbeckva said:
Pull the 410 where you are getting the zero from, then measure between it's collector lead (or where the screws normally go) and ground.

These caps here ... the orange guys. Also those diodes that go between the leftmost and rightmost tiepoints on the center terminal blocks.

View attachment 14916
Click to expand...
There are no such capacitors in this amplifier.
 
laatsch55

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OK, let's try this again.....zero ohms means no resistance=continuity, OL on the meter means infinity, as in no continuity. No part of any output device referenced to ground should show continuity...
 
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62vauxhall said:
I'm not following. With sil pads in place isolating the 410 cases from ground, didn't that explain zero Ohms?

Answer to question is all four 410's produced aero Ohms.
Click to expand...
The Sil-Pads provide electrical isolation while being a good conductor of heat. So zero ohms is not a good thing - if you took your ohm meter and measured the resistance of the pad by itself you should see OL or a very high resistance.
 
62vauxhall

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laatsch55 said:
OK, let's try this again.....zero ohms means no resistance=continuity, OL on the meter means infinity, as in no continuity. No part of any output device referenced to ground should show continuity...
Click to expand...
My mistake. Thought in the case of resistance OL and Zero ohms were synonymous.

I did get OL on all four 410's.

But, and I just saw now this happen, immediately upon touching Q12's case with the probe, there is resistance then after a few seconds, goes to OL. I guess previously I did not look at the meter until after OL appeared in the display. So there is resistance present for both Q12's for a period of about 4 to 5 seconds.
 
62vauxhall

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Valve adjustment took longer than expected and I just got home. But as soon as I arrived, I got a call and now have to leave again for a while.

I'll post again when I'm back from this unexpected errand.
 
62vauxhall

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In the future I may not be so forthcoming to offer help as I have been.

A woman friend asked for help which "...would only take a couple of minutes" getting a mattress and box spring up some stairs to the floor above. Another of her friends was to be there but he was nearly two hours late. The mattress and box spring turned into a whole bedroom suite, sofa, recliner dining room table and china cabinet.

In the process of up and down stairs, I did something to my knee. It hurts to walk and I can barely get in and out of my car. Figures too that today I spend $550 on motorcycle maintenance and at the moment, I'm not able to ride it.

No choice but to post again tomorrow and see if you're ready to do battle with this amp again.
 
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