BIG problems

[laatsch55]

No it's not. There are some amps that all you will do is piss off the soft start, a variac is especially useful. Take it to 20%, wait for the bulb tro dim, walk it up another 20%, etc...

 

[Michael F]

Alright then. It`s got a volt and ammeter, what kind of current draw would be deemed acceptable at the various voltages?

Should I bolt the heat sinks on with only the drivers running?

 

[laatsch55]

Can't mount the TO-3's without the heatsinks! Do you have the meter on each side of R38??

 

[laatsch55]

Acceptable current draw is the bulb going dim....

 

[Michael F]

Can't mount the TO-3's without the heatsinks! Do you have the meter on each side of R38??

10-4. I`ll be testing in the PM, too tired now. This thing better f#@*&%^g work

 

[laatsch55]

I'm working till about 2 in the afterniin tomorrow. Good amping!!

 

[NavLinear]

I'm working till about 2 in the afterniin tomorrow. Good amping!!

Is that Dutch? We might need a translator.

 

[laatsch55]

FFS, AGAION

 

[Michael F]

Round 1

DBT passes, however, 40vdc on right output, .022 on left

 

[Gepetto]

DBT passes, however, 40vdc on right output, .022 on left

Plus or minus on both readings. Polarity matters to help debug what might be your problem.

Assuming the 0.022V is really -0.022V The offset is typically in the slight negative direction due to the bias current of the front end differential pair.

 

[Gepetto]

Did you check that Q6 (2N3403) was good on both channels before starting?

 

[laatsch55]

And if you have 40VDC in the outputb terminals and it is not blowing fuses it's usually contained in the board.

 

[Michael F]

Plus or minus on both readings. Polarity matters to help debug what might be your problem.

Assuming the 0.022V is really -0.022V The offset is typically in the slight negative direction due to the bias current of the front end differential pair.

Plus on both readings

 

[Gepetto]

Plus on both readings

Check Q6 (chassis mounted) on that right channel that has 40V on it. If Q6 is good then next check Q7 and Q10.

 

[Michael F]

Check Q6 (chassis mounted) on that right channel that has 40V on it. If Q6 is good then next check Q7 and Q10.

Q6,7 and 10 check out OK in circuit, they measure the same as their left channel counterparts

 

[laatsch55]

Have you double checked the pinouts? Solder bridges? Did you replace any of the diodes? And double check the back to back you put on C6 to make sure they're going opposite of each other.

 

[laatsch55]

Could you list what went in q1-q10??

 

[Michael F]

Could you list what went in q1-q10??

Q1 MPS5172
Q2 Same
Q3 2N5401
Q4 Same
Q5 2N3439
Q6 2N3415
Q7 2N5415
Q8 2N1304
Q9 2N1305
Q10 2N3440

 

[Michael F]

DBT passes, however, 40vdc on right output, .022 on left

Would you consider Left channel to be good? I can use it as a reference.

 

[laatsch55]

Good enough for a reference, yes. Q4 should not have been used for Q4. Q4 is the hardest working TO-92 in there. The e-bay seller should know that. It'll do to get you up and running, but it's not something that inspires a medal for reliability. Are you sure about Q6's number??