Where to find 6000uF 50V replacement cap cans??

[RG100ESROX]

Yes, DC volts to ground.
Good luck to Utah in the NHL game Tues. (old Jets vs new Jets). 

Thanks! We'll take all the luck we can get!

I'll have those voltage readings for you on Thursday.

Thanks again!!

[RG100ESROX]

Here are the voltage readings you requested for Q-8 thru Q-16.

Voltages are located by the location they were taken within a white square. (maybe it's just me, but the voltage readings don't seem like they are what would be expected (e.g.: -18VDC/-31VDC/+31VDC...strange)

Voltages were taken with a supply voltage of 110VAC because of the current limiter light bulb glow.

Let me know if you have any questions.

-Jay

[Jazz P Bass]

Those voltage readings are not good.
Especially the -18 volts on the output bases.

[RG100ESROX]

Those voltage readings are not good.
Especially the -18 volts on the output bases.

So, what should I be checking next? What would be the cause of these odd/bad voltages???

I do have the following parts on hand if needed...

.18R 10 watts x 2
.27R 10 watts x 4
.62R 10 watts x2
2N5484 FETs x 20
TIP31C x 10
TIP32C x 10
2N6254 x 5
Many assorted 1/2 watt Carbon Film resistors

[g1]

For now, focus on the TIP32 nearest to the trimpot (Q10).
You show +30V at the emitter.  It is a PNP transistor, so if good, the base can only be 0.7V more negative.  Yet you show -18V at the base, which is impossible if the transistor is good.

[RG100ESROX]

For now, focus on the TIP32 nearest to the trimpot (Q10).
You show +30V at the emitter.  It is a PNP transistor, so if good, the base can only be 0.7V more negative.  Yet you show -18V at the base, which is impossible if the transistor is good.

Okay, I'll take a reading on the TIP32C again and get back to you.

Should I be able to get a resistance reading on the 250K bias trim pot? Because I am not able to measure any resistance from any point to any point, or from any point to ground. Does this trim pot have to be removed from the board before a resistance measurement can be taken? Or is the pot bad?? I have some coming just in case.

Thanks in advance!!

-Jay

[g1]

The trim pot should be 250R, not 250K.  You should be able to measure it in circuit.  And there should be a resistor, R51 in parallel with it (value somewhere between 47R and 100R).
What do you mean, 'not able to measure resistance', is it giving you 'OL' indication?  Otherwise, a reading of zero ohms indicates a short circuit.  Always state the reading the meter shows.

[RG100ESROX]

The trim pot should be 250R, not 250K.  You should be able to measure it in circuit.  And there should be a resistor, R51 in parallel with it (value somewhere between 47R and 100R).
What do you mean, 'not able to measure resistance', is it giving you 'OL' indication?  Otherwise, a reading of zero ohms indicates a short circuit.  Always state the reading the meter shows.

Yes; it is. You are correct. I just have 'K' on the brain.

I'm not getting a reading when I probe the two front lugs (the reading was erratic and would not settle anywhere), or front to side like I thought I should. And at some point I would think that the DMM would show me 250R regardless of where I have the trim pot set and it's not.

At this point I should probably remove it and try to get a measurement on it out of the circuit. I'll be specific with the readings I measure in my next reply.

[RG100ESROX]

Readings on the trim pot: (trim pot set to minimum and maximum setting)
Two middle left lugs = 9.0 ohms min/ 39.0 ohms max
top middle to top lug = 9.0 ohms min/ 39.0 ohms max
Bottom middle to bottom lug = 0.3 ohms min/ 0.3 ohms max
Top lug to bottom lug = 0.3 ohms min/ 0.3 ohms max

DMM set to diode test mode:
First TIP32C (Red lead on Collector)
B to C = .556v
E to C = .441v

Readings on the TIP31C (black lead on Collector)
B to C = .537v
C to E = .443v

Second TIP32C - w/heatsink (Red lead on Collector)
B to C = .540v
E to C = .540v

Let me know what ya think and what I should check next.

Thanks in advance.

-Jay

[g1]

Do diode check for E-B on three transistors above.  With black lead to base, then with red lead to base.

[RG100ESROX]

Do diode check for E-B on three transistors above.  With black lead to base, then with red lead to base.

1st TIP32C black to B/E = .562v
Red to B/E = .590v

2nd TIP32C black to B/E = .284v
Red to B/E = .284v

TIP31C black to B/E = .602v
Red to B/E = .552v

[g1]

2nd TIP32C black to B/E = .284v
Red to B/E = .284v

Disconnect either the base or emitter from the circuit.  Re-check.

[RG100ESROX]

Do diode check for E-B on three transistors above.  With black lead to base, then with red lead to base.

You didn't comment on it, but I'm assuming the bias pot is okay based on the fact that there is a 48R resistor in parallel with it?

I'm actually surprised that the bias range of this amp is so narrow. Is this typical for a SS amp??

[RG100ESROX]

2nd TIP32C black to B/E = .284v
Red to B/E = .284v

Disconnect either the base or emitter from the circuit.  Re-check.

Will do!!

[RG100ESROX]

2nd TIP32C black to B/E = .284v
Red to B/E = .284v

Disconnect either the base or emitter from the circuit.  Re-check.

2nd TIP32C with base removed from board/circuit black to B/E = .596v
Red to B/E = .OL