Yamaha R-700 safety relay question.

R380

I pulled R380 and measured it - yes 220K ohm. Then without it I got 26v dc on 1 and 0 on the other terminal.
The with it in, I got 16v in the one that read 26v, and somehting like .4v on the other one.

Thanks.
Srinath.
 
Suspect C369 is shorted. Pull it and replace it. Or TR305 is shorted. C369 is mounted right next to TR305.
 
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I swapped 369 already but I'll do TR305 in a bit.

Cool.
Srinath.

What did you replace it with? Was it a 47µf/35vdc? Check your soldering for solder bridges. Double check for correct polarity*!

* positive lead should connect to the collector of TR305
 
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In that other amp

What did you replace it with? Was it a 47µf/35vdc? Check your soldering for solder bridges. Double check for correct polarity*!

* positive lead should connect to the collector of TR305

I replaced it with that was in my parts amp. 47mf/6.3v.

I swapped tr305 with one form the parts amp and it didn't change the situation.

I'll check polarity now.
Cool
Srinath.
 
I replaced it with that was in my parts amp. 47mf/6.3v.

I swapped tr305 with one form the parts amp and it didn't change the situation.

I'll check polarity now.
Cool
Srinath.

C368 is 47µf/6.3 according to the schematic.
 
Next possibility TR306 and 307 --Your pulling parts from a parts unit, correct ? Are testing these components before installing into your UUT?
 
I am testing them, but the parts unit has had these replaced. The TR305-308 is significantly smaller than the originals.

Thanks.
Srinath.
 
And I am not sure if the parts unit had a repair started and the guy gave up, or if it happened after repair with subsequent use - but the parts amp had a blown R412 - same as the one I am fixing. Its a good argument to get new transistors I guess - Let me get these out and tested, maybe its good. I actually need to find my transistor tester, I seem to have put it in storage.

Cool.
Srinath.
 
The 2sa999 - the cross reference says its equivalent to the 2sa992 and an NTE290. I have to look @ what I got in the thing, as well as the rest of these transistors the 2sc2320's.
Cool.
Srinath.
 
the 2sa999 - the cross reference says its equivalent to the 2sa992 and an nte290. I have to look @ what i got in the thing, as well as the rest of these transistors the 2sc2320's.
Cool.
Srinath.

----- 2sa999(ecb)----ksa1015(ecb)
----- 2sc2320(ecb)---ksc2383(ecb)
 
OK the little transformer - makes 2.7v ac, it gets 117 and outputs 2.7.
I am near certain its low, isn't that supposed to be like 16 or so.
Cool.
Srinath.
 
Don't get sidetracked.. That transformer is for memory backup power supply for all your presets. Has nothing to do with the protect circuit.
 
I'll get back to this, double check my work, and swap out the ones I haven't changed with the parts amp, and if it starts working, great. Else I may have to refit it and put it away in storage, I cant wait for parts, I thought fixing it would be better since it was in 1000 pieces, over just re assembling, but ordering parts, I am going to lose it in the move, so I may just print out this thread, put it inside the case and put it away.
Cool.
Srinath.
 
C369 as per manual is 47mf 35V. Both my amp and the parts amp have 22mf 25v.
c368 as per manual is 100mf 6.3v. Both amps have 47mf 6.3v

Why are these 2 off - I think they updates the schematic arbitrarily @ some point between making the amp and printing the manual.

Should I follow the manual ? So I'd have to get the caps (common enough, I'll probably gut something for it today) or stay with the amp's original parts ? Afterall it should have worked till it blew out.

Cool.
Srinath.
 
Ok

The amp parts are not making a diff, and I dont have the 2 parts from the manual. Only had one, swapped that in and didn't do noting different.
I am probably going to have to slap this shut and put it away. A move and a new house awaits.
Always time to chew on this later I guess.

Cool.
Srinath.
 
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