Hartke 3500

[shortcircuit]

You said you don't have IC's on the FX loop board, so that schematic in post #27 should be correct or very close.
You don't need +/-15V on the loop board then.
Try the patch cord connecting send to return again.

jumping s to r just tapping on instrument cable at passive input , has a definite increase in power, where is my missing link ??

[g1]

You had a burnt resistor R501 on the loop board, there is probably another bad one there or a burnt trace or something. And double check you got the right value for R501.

[shortcircuit]

You had a burnt resistor R501 on the loop board, there is probably another bad one there or a burnt trace or something. And double check you got the right value for R501.

double check R501 100ohm , other 4 10k resistors all test good out of circuit , in circuit with s/r vol at 10 I get R501 10k, 502 10k ,503 6K, 504 6K, 505 4.7k . I have found I get my power back when I turn the s/r vol to 0 , with no jumper.
readings on resistors with s/r vol at 0 R501 10K, 502 10K, 503 7.25K, 504 21.5 ohm

[g1]

I'm not sure exactly what version this is, but some of them have a 'balance' pot for the loop. It has a center detent that is labelled '0' on the rear panel. That is where you run it with nothing in the loop. At full 'wet', if you have nothing in the loop you will lose your sound.
It sounds like that may be what you have, if so, it is normal.

[shortcircuit]

I'm not sure exactly what version this is, but some of them have a 'balance' pot for the loop. It has a center detent that is labelled '0' on the rear panel. That is where you run it with nothing in the loop. At full 'wet', if you have nothing in the loop you will lose your sound.
It sounds like that may be what you have, if so, it is normal.

You are correct I missed that when I looked up the manual. All you support members are fantastic, can't thank you all enough.

[J M Fahey]

A little late and apparently the dog ate my homework ... errrr .... my answer to your post #12 .
In any case, and for future reference:

I'm suspect of Q309 I have my b+ at the collector , not at the emitter , have b+ at collector not the base on q313 thru 319. I should have it here correct.

No.
+B on collectors is fine, they are fed straight from it, but both bases , under static conditions (no signal), must only have bias voltage on them, so "one diode" (about +0.6V) on Q313 base, and "two diodes" or some 1.3V on Q309 base.

And each emitter "one diode" down, so basicall 0V on Q313 emitter and "one diode" on Q309 emitter.

[shortcircuit]

A little late and apparently the dog ate my homework ... errrr .... my answer to your post #12 .
In any case, and for future reference:

No.
+B on collectors is fine, they are fed straight from it, but both bases , under static conditions (no signal), must only have bias voltage on them, so "one diode" (about +0.6V) on Q313 base, and "two diodes" or some 1.3V on Q309 base.

And each emitter "one diode" down, so basicall 0V on Q313 emitter and "one diode" on Q309 emitter.

Thank you , you've made my shade of green a little bit lighter

[The Dude]

You are correct I missed that when I looked up the manual. All you support members are fantastic, can't thank you all enough.

Does that mean the amp is fixed and working as it should, or are there still problems?

[shortcircuit]

Does that mean the amp is fixed and working as it should, or are there still problems?

I am taking the amp to the owner for a test drive , so I can't answer as it should/problems , just yet.

[shortcircuit]

Does that mean the amp is fixed and working as it should, or are there still problems?

I can now say job well done , the amp is up and running . Could not have done it without the great support from this site,you are all incredible !!!!

[The Dude]

And, easier, cheaper, and faster than changing entire boards. Glad you got it!

[shortcircuit]

And, easier, cheaper, and faster than changing entire boards. Glad you got it!

touche' and thanks again