Hartke 3500

[shortcircuit]

Have you tried a cable between the send and return jacks on the back panel?

yes have tried that, no change thanks for the input

[Enzo]

I don't find 2pin an404 which is on the send /return on the schematic , I have a 3pin con coming from an401 off the pre board I get -14v on both pin 1 & 3 0v at pin 2 on the pre board not at the send/return all the traces on the harness check good

The jack board is in more than one place around the drawing. If your loop ICs have no power, they pass no signal. Follow the traces or whatever you have to do to get power to the IC on the loop jack board.

Looking at AN401/CN401, no way should there be -14v on any pin of it. However, if IC501 is missing its +14, then the rest of it snaps over to -14, which would appear on pin RE of CN401.

[shortcircuit]

The jack board is in more than one place around the drawing. If your loop ICs have no power, they pass no signal. Follow the traces or whatever you have to do to get power to the IC on the loop jack board.

Looking at AN401/CN401, no way should there be -14v on any pin of it. However, if IC501 is missing its +14, then the rest of it snaps over to -14, which would appear on pin RE of CN401.

Thank you Enzo,
I do not have -14 at cn4001 re , I don't have an IC501 , I have a 3500B and now that we've moved to the pre amp board it's a totally different set up and I don't have that schematic yet. would you happen to have it 4005198000a main brd. / 4005197000 pwr amp brd? before I go any farther I will try and get one. I apologize for starting the thread wrong should have called it 3500B
Thanks
The fool on the hill

[The Dude]

You're not likely to find boards and, if you did, they would be costly. Plus at this point it's a guess as to which board(s) you need. You could spend a fortune on boards and the thing still won't work. It shouldn't be that hard to fix. Is there and op amp on the send/return jack board in the amp you have in front of you? It matters not what the designation number is. If there is one, it's not going to work without +&-15V. You'll have to trace it back and find out why it's not getting there.

[shortcircuit]

The jack board is in more than one place around the drawing. If your loop ICs have no power, they pass no signal. Follow the traces or whatever you have to do to get power to the IC on the loop jack board.

Looking at AN401/CN401, no way should there be -14v on any pin of it. However, if IC501 is missing its +14, then the rest of it snaps over to -14, which would appear on pin RE of CN401.

Taking your advice in principle I traced down the loop found a resister R501 on the jack board that didn't test well,replaced. I now have sound if I run a jumper cable between send and return. Tried the amp still have no real volume and it sounds like a blown speaker, distorted , regardless which pre I use tube or ss , with both off.

[shortcircuit]

yes have tried that, no change thanks for the input

Taking your advice in principle I traced down the loop found a resister R501 on the jack board that didn't test well,replaced. I now have sound if I run a jumper cable between send and return. Tried the amp still have no real volume and it sounds like a blown speaker, distorted , regardless which pre I use tube or ss , with both off.

[shortcircuit]

You're not likely to find boards and, if you did, they would be costly. Plus at this point it's a guess as to which board(s) you need. You could spend a fortune on boards and the thing still won't work. It shouldn't be that hard to fix. Is there and op amp on the send/return jack board in the amp you have in front of you? It matters not what the designation number is. If there is one, it's not going to work without +&-15V. You'll have to trace it back and find out why it's not getting there.

Sorry I'm so green, was looking for the actual schematics for the boards listed.There is no op amp , no IC at all on send /return board , I was typing a reply relevant to what your saying , I replaced R501 on jack board , now if I jump send/return I have sound, it's distorted but a signal, but I do not have +15/-15 anywhere on the jackboard or at an401 which feeds it. I agree something simple/stupid is going on,I'm just to simply stupid to find it , I'm learning. I can't thank everyone enough on the forum for there help and patience.Don't throw me to the dogs just yet.

[The Dude]

.......Don't throw me to the dogs just yet.

That's not the intent at all. We're just trying to save you from spending lots of money for nothing,........ if it were possible. I doubt seriously that the boards are available anyway.

So, no IC on the Send/Return board. If that's the case and R501 burnt, assuming it's off the send jack like the wrong schematic we are looking at, my guess is that some really hot signal was input there by accident. I'd look at the first op amp in from there, maybe IC107 op amp. It may have taken a hit. What are the voltages on pins 1 and 7 of that IC?

Edit: You may have to do some tracing. IC107 may not be the first op amp in from the Send/Return board since our schematic is not the exact right one.

[shortcircuit]

That's not the intent at all. We're just trying to save you from spending lots of money for nothing,........ if it were possible. I doubt seriously that the boards are available anyway.

So, no IC on the Send/Return board. If that's the case and R501 burnt, assuming it's off the send jack like the wrong schematic we are looking at, my guess is that some really hot signal was input there by accident. I'd look at the first op amp in from there, maybe IC107 op amp. It may have taken a hit. What are the voltages on pins 1 and 7 of that IC?

Edit: You may have to do some tracing. IC107 may not be the first op amp in from the Send/Return board since our schematic is not the exact right one.

IC107 -14 at both 1 & 7

[The Dude]

If you have +15 at pin 8, I'm betting the IC is shorted. I'd replace it.

[shortcircuit]

If you have +15 at pin 8, I'm betting the IC is shorted. I'd replace it.

I do have +15 at pin 8 , I will replace it , might take a few(days) to find one . Once again thank you so much.

[g1]

I think this schematic may have your fx loop circuit.

[shortcircuit]

Thank you g1

[shortcircuit]

I have replaced ic107 , I still do not have +15/-15 any where on return/send jack board, how ever I now have a signal plugging into the return jack , it's a clean sound . Plugging into passive front input jack I have a clean sound , but I don't have much output , I can crank this and it gets maybe the volume of a 5 watt amp. Any suggestions ?? I feel one step away from this coming back to life. Still waiting for a reply from Hartke on a 3500B schematic

[g1]

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.