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2215B Self Inflicted Damage - Help

Alaska Bill

Alaska Bill

Member
Was going to adjust the R728 until I got 10mV on R736 and touched the probe between R736 and the silver bar (see highlighted yellow on image). Spark and went dead. Main fuse blown; replaced with 2A as was in there and powered up: Lights on for about 1 second, then dead; fuse blown again.

Suggestions on how to proceed to troubleshoot is MUCH appreciated. I have a decent multimeter, and am able to solder etc. Feel like a real dummy tho, having done this to myself.
 

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He's dead, Jim...
Looks like blown output transistors, at least.:tears:
Use the diode test on your multimeter to check the junctions in the outputs (out of circuit)
[URL="http://audiokarma.org/forums/showthread.php?t=43186]Transistor testing with a multimeter[/URL]
Oh, and say 'Thank You' to EchoWars.


Tom
 
OK will remove tomorrow and test and post results. Testing insitu was not enlightening. If burned out, are they available? Sanyo D313D 6D (NPN) and Sanyo B507D PNP. Thanks for the help.
 
Since I measured insitu, I may as well post the results; maybe the values are meaningful to someone.
P313D 6D (Schematic H712)
B C E RESULT
R B X 0.559
R X B 0.564
B R X 0.619
B X R 0.654
X R B 0.904
X B R 0.919

B507D 6CR (Schematic H714)
R B X 0.683
R X B 0.701
B R X 0.534
B X R 0.545
X R B 0.905
X B R 0.918

P313D 6D (Schematic H711)
B C E RESULT
R B X 0.004
R X B 0.004
B R X 0.004
B X R 0.004
X R B 0.000
X B R 0.000

B507D 6CR (Schematic H713)
R B X 0.186
R X B 0.186
B R X 0.185
B X R 0.184
X R B 0.000
X B R 0.000

Will remove and retest tomorrow and post results. Any other transistors I should check also? (These 4 are the ones on the big heat sink). Thanks.
 
Oddly you said you were adjusting R728 and your probe touched R736. According to the schematic that's where H712 and H714. I am not sure about your meter but my meter even in diode test would show 0.000 for short and according to your list of your measurments, H711 and H713 appears to be shorted (damaged outputs). Are you sure you got the output numbering right?
 
Correction

Good Catch! I measured from the bottom side of the foil and got my numbering mixed up.

P313D 6D (Schematic H711)
B C E RESULT
R B X 0.559
R X B 0.564
B R X 0.619
B X R 0.654
X R B 0.904
X B R 0.919

B507D 6CR (Schematic H713)
R B X 0.683
R X B 0.701
B R X 0.534
B X R 0.545
X R B 0.905
X B R 0.918

P313D 6D (Schematic H712)
B C E RESULT
R B X 0.004
R X B 0.004
B R X 0.004
B X R 0.004
X R B 0.000
X B R 0.000

B507D 6CR (Schematic H714)
R B X 0.186
R X B 0.186
B R X 0.185
B X R 0.184
X R B 0.000
X B R 0.000
 
In that case. It definitely looks like your outputs (H712 and H714) are blown. I had the same problem with my Kenwood when I bought it knowing it was dead. Would not power up (blowing fuses) and found 2 outputs were blown. I would suggest when you replace the outputs, you might want to check the 2 resistors between the emitters and also if I were you I would check all the transistors on the affected side especially your driver transistors to make sure they're not shorted as well or you may blow the replacement set of outputs.
 
Re-Cap

If I recap, after I get it working, are only the electrolytic caps replaced? Just looking ahead, positively.

Thanks...such a great forum
 
I did the same thing to a sansui au-999 and it took that amp sitting in my closet for years before I tackled it.

Best of luck! Sounds like you found the probelmo.
 
Alaska Bill said:
If I recap, after I get it working, are only the electrolytic caps replaced? Just looking ahead, positively.

Thanks...such a great forum
Click to expand...
QUOTE=Alaska Bill;1590551]If I recap, after I get it working, are only the electrolytic caps replaced? Just looking ahead, positively.

Thanks...such a great forum[/QUOTE]

Generally, the electrolytics and any tantalums are replaced when re-capping.
As for the outputs, MCM lists Sanyo parts as in-stock, less than a buck each.
2SB507
2SD313


Tom
 
Out of Circuit Test Results

Out of circuit:
D313D Schematic H712
B C E RESULT
R B X 0.005
R X B 0.005
B R X 0.005
B X R 0.005
X R B 0.000
X B R 0.000

B507D Schematic H714
B C E RESULT
R B X 0.299
R X B 0.299
B R X 0.295
B X R 0.296
X R B 0.000
X B R 0.000

Sm on Heat Sink Schematic H706
B C E RESULT
R B X 0.708
R X B 0.714
B R X OL
B X R OL
X R B OL
X B R OL

Sm on Heat Sink Schematic H705
B C E RESULT
R B X 0.708
R X B 0.708
B R X OL
B X R OL
X R B OL
X B R OL

B507D Schematic H713
B C E RESULT
R B X OL
R X B OL
B R X 0.546
B X R 0.555
X R B OL
X B R OL

D313D Schematic H711
B C E RESULT
R B X 0.570
R X B 0.574
B R X OL
B X R OL
X R B OL
X B R OL

So does this mean H712 and H714 are bad and the rest are OK? Should I take any more transistors out and test them?

When replacing H712 and H714, should I be replacing H711 and H713 at the same time even though they are OK?

Thanks for the help gent's; and a special thanks to EchoWars for the nice tutorial on how to test.
 
Alaska Bill said:
So does this mean H712 and H714 are bad and the rest are OK?
Click to expand...
What does your spidey-sense tell you?
Should I take any more transistors out and test them?
Click to expand...
As you can see, transistors generally short from collector to emitter. Do cursory tests in-circuit, and remove if you suspect a short. If you power the unit up after repair with a current-limited supply (search: dim-bulb tester, probably ought to use about a 60W lamp with this small amp) you ought to be able to see if you got all the bad guys.
When replacing H712 and H714, should I be replacing H711 and H713 at the same time even though they are OK?
Click to expand...
Depends on if you need to find substitute parts, or if you go with original part #'s.
 
You're welcome. I hope it works out for you. Just after you fix it, watch your probes. I would recommend using one of those probes that you can push and clip it on the terminal. I'm not talking about alligator clips. I use that rather than the regular probes. No accident "yet". I made several close calls with regular probes. Sometimes did short something sometime ago with regular probes. With clips I haven't shorted anything yet. Still be cautious especially narrow space between terminals.

I can't think of the name of that doggone clips. Maybe some AK'ers will beat me to it.
 
Interm Report Card

An Update - replaced the 2 power transistors, using NTE153MCP, on the one channel and now back in business playing nice music! Thanks again all.

Will wait until the service manual comes (on order) and then more carefully this time, adjust the bias. And possibly re-cap it to.
 
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