700B blew one Right channel 5A supply fuse

[Gepetto]

Wire color on my board leaves something to be desired but seems to concur with what you sent in the link.

It is not UV resistant and fades with time. Crappy wire was used in these.

 

[laatsch55]

I daresay it's not heat resistant either....

 

[Gepetto]

I daresay it's not heat resistant either....

You are right Lee. Crappy PVC with no meltback resistance and no UV resistance.

 

[laatsch55]

The FaboNav has roont me....going back is unthinkable..

 

[Gepetto]

The FaboNav has roont me....going back is unthinkable..

High quality is a very good thing...

 

[laatsch55]

What does it mean when it's the ONLY thing?

 

[62vauxhall]

I stand corrected. The left side of my board agrees with your link but the right side does not.

The blue wire at pad 9 goes to Q11 base as it should but the violet wire and striped wire are swapped. I made the correction and left the violet wire off. Guess I wan't as careful as I thought I was although I'd swear on a stack of bibles thatI put those wires back on exactly the same way they came off.

With no wires from the board connected to Q11 base and Q12 base on either channel, the bulb lit brightly then dimmed to off in a few seconds. The resistors at the speaker terminals remained intact during the 30 seconds or so that I had the amp plugged in.

 

[laatsch55]

While in this configuration with power off and rail fuses out, go back through all 10 transistors on each side of the board. A quick runthrough to check forward voltage, standard semiconductor test. With those wires being backwards that could hurt the small signal trannys. Just a quick runthrough... 3 tests in circuit B-E, B-C C-E...

 

[laatsch55]

You have eliminated the backwall as the source of problems now...

 

[62vauxhall]

Do that test without re-connecting the wires to Q11 and Q12?

 

[laatsch55]

Yes, just looking for obvious shorts and opens before hooking the wires back up and dim bulbing again...

 

[62vauxhall]

Sorry for needing to rehash old information. Before I test those transistors, can you please advise on the pinout pattern for the TO39's? I've gotten confused looking at datasheets and comparing them to the schematic.

If I understand correctly, Base is consistently in the same position but I'm unsure of Emitter and Collector.

I've numbered the pins according to a topside view but that might be my incorrect interpretation of the diagrams I've seen.

If you could "fill in the blanks" it would be greatly appreciated.

 

[laatsch55]

The emitter is closest to the small metal tab on the side and the collector is common with the case...

 

[62vauxhall]

Thanks. I did see that reference about tab being closest to emitter but what I read said "in most cases" plus it was dated 2002 so I was hesitant.

The Q11 and Q12 wires are still disconnected and the rail fuses are out.

I just now realized those resistors are still in place at the speaker terminals. Would removing them have had any effect on these readings I got from the transistors?

I measured both ways across the points you you said so it's a long list. Red ​indicates where I placed the red test lead.

Unless leaving the resistors in place makes a difference (which I will remove and re-measure if so) your speculation about damaged transistors seems right.

Left channel Q1 - TIS97
B to E - OL
E to B - .659
B to C - OL
C to B - .658
C to E - OL
E to C - OL

Left channel Q2 - TIS97
B to E - OL
E to B - .665
B to C - OL
C to B - .664
C to E - OL
E to C - OL

Left channel Q3 - TIS93
B to E - .585
E to B - OL
B to C - .606
C to B - OL
C to E - OL
E to C - OL

Left channel Q4 - MPSA93
B to E - .644
E to B - OL
B to C - .050
C to B - OL
C to E - OL
E to C - .916

Left channel Q5 - 2N3439
B to E - .734
E to B - .560
B to C - OL
C to B - .566
C to E - ascending past .700
E to - OL

Left channel Q6 - 2N5088
B to E - .831
E to B - .828
B to C - OL
C to B - .669
C to E - OL
E to C - OL

Left channel Q7 - 2N5416
B to E - .571
E to B - OL
B to C - .544
C to B - OL
C to E - OL
E to C - OL

Left channel Q8 - 2N1304
B to E - .048
E to B - OL
B to C - OL
C to B - .107
C to E - OL
E to C - OL

Left channel Q9 - 2N1305
B to E - .047
E to B - ..047
B to C - .470
C to B - .047
C to E - OL
E to C - ,121

Left channel Q10 - 2N3439
B to E - OL
E to B - .580
B to C - OL -
C to B - .580
C to E - OL
E to C - OL


Right channel Q1 - TIS97
B to E - OL
E to B - .666
B to C - OL
C to B - .665
C to E - OL
E to C - OL

Right channel Q2 - TIS97
B to E - OL
E to B - .666
B to C - OL
C to B - .665
C to E - OL
E to C - OL

Right channel Q3 - TIS93
B to E - .669
E to B - OL
B to C - .659
C to B - OL
C to E - .892
E to C - OL

Right channel Q4 - MPSA93
B to E - OL
E to B - OL
B to C - OL
C to B - OL
C to E - OL
E to C - OL

Right channel Q5 - 2N3439
B to E - .730
E to B - .561
B to C - OL
C to B - .556
C to E - ascending past .700
E to C - OL

Right channel Q6 - 2N5088
B to E - .718
E to B - .618
B to C - OL
C to B - .618
C to E - .787
E to C - OL

Right channel Q7 - 2N5416
B to E - .574
E to B - OL
B to C - .547
C to B - OL
C to E - OL
E to C - OL

Right channel Q8 - 2N1304
B to E - .047
E to B - OL
B to C - OL
C to B - .107
C to E - OL
E to C - OL

Right channel Q9 - 2N1305
B to E - OL
E to B - OL
B to C - .118
C to B - OL
C to E - OL
E to C - .124

Right channel Q10 - 2N3439
B to E - OL
E to B - .586
B to C - OL
C to B - .578
C to E - OL
E to C - OL

 

[laatsch55]

Gary, ya didn't need to do all those measurements, just the 3 per transistor. Pull the resistor off the output jacks, sorry I didn't mention that as I said "in this configuration"....what I wanted you to do is the standard 3 jct test for the NPN's on the NPN's, and the standard 3 jct test for the PNP's on the PNP's.......In circuit on Q5, Q7, and Q10 you will get some other reading which are the interactions with other components....we will address thenm later if there are readings that shouldn't be there.

The standard NPN test is positive on base, PNP negative on base....leave the base lead on the base and toggle to the emitter, then the collector. Run through those and tell me what ya get....

 

[laatsch55]

One thing for sure, right channel Q4 is toast, I believe I sent more than 4 though/....

 

[62vauxhall]

Yes, you did send extra MPSA93's for Q4.

The resistors have been removed from the speaker terminals and rail fuses still out.

Same as before, Red indicates where that test lead was placed which was I hope, correct.

Q1 Left channel TIS97 pnp
B to E - OL
B to C - OL
C to E - OL

Q2 Left channel TIS97 npn
B to E - OL
B to C - OL
C to E - OL

Q3 Left channel TIS93 pnp
B to E - OL
B to C - OL
C to E - OL

Q3 Left channel TIS93 pnp
B to E - OL
B to C - OL
C to E - OL
'
Q4 Left channel MPSA93 pnp
B to E - OL
B to C - OL
C to E - OL

Q5 Left channel 2N3439 npn
B to E - OL
B to C - OL
C to E - ascends past .800

Q6 Left channel 2N5088 npn
B to E - .828
B to C - OL
C to E - OL

Q7 Left channel 2N5416 pnp
B to E - OL
B to C - OL
C to E - OL

Q8 Left channel 2N1304 npn
B to E - .047
B to C - OL
C to E - .110

Q9 Left channel 2N1305 pnp
B to E - .047
B to C - .122
C to E - .121

Q10 Left channel 2N3439 npn
B to E - OL
B to C - OL
C to E - OL


Q1 Right channel TIS97 pnp
B to E - OL
B to C - OL
C to E - OL

Q2 Right channel TIS97 npn
B to E - OL
B to C - OL
C to E - OL

Q3 Right channel TIS93 pnp
B to E - .000
B to C - .664
C to E - OL
'
Q4 Right channel MPSA93 pnp
B to E - OL
B to C - OL
C to E - OL

Q5 Right channel 2N3439 npn
B to E - .725
B to C - OL
C to E - ascends past .800

Q6 Right channel 2N5088 npn
B to E - .716
B to C - OL
C to E - .736

Q7 Right channel 2N5416 pnp
B to E - OL
B to C - OL
C to E - OL

Q8 Right channel 2N1304 npn
B to E - .047
B to C - OL
C to E - .107

Q9 Right channel 2N1305 pnp
B to E - .OL
B to C - .PL
C to E - .123

Q10 Right channel 2N3439 npn
B to E - OL
B to C - OL
C to E - OL

 

[laatsch55]

Gary, take one of those brand new 21196's and run, a quick test. They are NPN's. I think you have to be opposite of what I'm saying because your meter doesn't reverse the leads internally.....which is what most meters do, I have forgotten just exactly why... Try the NPN test , then the PNP test...

 

[laatsch55]

Gary, Q1,Q2 are NPNs, Q3,Q4 PNP's, Q5 NPN, Q6 NPN, Q7 PNP, Q10 NPN>..

 

[62vauxhall]

Gary, take one of those brand new 21196's and run, a quick test. They are NPN's. I think you have to be opposite of what I'm saying because your meter doesn't reverse the leads internally.....which is what most meters do, I have forgotten just exactly why... Try the NPN test , then the PNP test...

21196's ?

I have spares of TIS97, MPSA93, and TIS93. I have written down that TIS97 is an NPN. Will that do?