Laney TT50H No Outout

[ca7922303]

Yes you can proceed the the HT issues. See post #240.
I'm really not sure what happened there, whether there will be some fault that wants to blow the fuse again. It seems this happened about the same time as the switching stopped functioning at all? But you never noticed anything?
If I had to take a wild guess I would have thought the midi board fell onto or touched the main board while running.

D2,3,4,5 read(0.5v) diode testC25,26,27,28(5.7nf)
D5(0.6m/22m ohms) resistance.
Replace D5?

[g1]

When your meter tests resistance, it is at very low current. So those connections may read ok but they are visually burnt. Once they need to pass current they will heat up and the resistance will rise. The HT lugs that are soldered to the board in your picture show the solder problems and both HT lugs should be resoldered. Inspect the connectors on the wires that go to the lugs visually and replace if they look burnt or overheated. The board is black there because of a problem.

[ca7922303]

When your meter tests resistance, it is at very low current. So those connections may read ok but they are visually burnt. Once they need to pass current they will heat up and the resistance will rise. The HT lugs that are soldered to the board in your picture show the solder problems and both HT lugs should be resoldered. Inspect the connectors on the wires that go to the lugs visually and replace if they look burnt or overheated. The board is black there because of a problem.

Ok, cleaned board and resoldered both HT pins, connectors look good. Anything about the readings I posted?

[g1]

I missed post #272 somehow. Yes, replace D5. However, they are cheap, and the others there may have been stressed. I would replace all four. (D2,3,4,5).

[ca7922303]

D2-5 is a 1N4007. Mouser shows about 60 with different prefixes, currents, and voltages. Do you know the forward and reverse currents, voltages, and maximum surge current. I know the length(.52 mm). Thanks.

[g1]

D2-5 is a 1N4007. Mouser shows about 60 with different prefixes, currents, and voltages. Do you know the forward and reverse currents, voltages, and maximum surge current. I know the length(.52 mm). Thanks.

When you use the mouser search, always click the box that says 'in stock'. Once I do that, there are only 14 to choose from. The 1N4007-T at the top of the list is fine. They have hundreds of thousands of them because they are the most common.

[ca7922303]

When you use the mouser search, always click the box that says 'in stock'. Once I do that, there are only 14 to choose from. The 1N4007-T at the top of the list is fine. They have hundreds of thousands of them because they are the most common.

Installed U6 using white thermal compound in photo. I'm seeing a maroon colored substance on board @ R13 & U2. Am I ok to use what I used on U6 or should I use something else? Thanks.

[g1]

Installed U6 using white thermal compound in photo. I'm seeing a maroon colored substance on board @ R13 & U2. Am I ok to use what I used on U6 or should I use something else? Thanks.

You don't need thermal paste on U2 or R13. That red stuff is just a fixative/glue to hold the part in place so it doesn't move when being soldered. Use something similar, get the pins lined up, and let it set before soldering. Nail polish will probably do the trick.
You should have a very fine tip on your solder iron to do this kind of surface mount stuff.

[ca7922303]

You don't need thermal paste on U2 or R13. That red stuff is just a fixative/glue to hold the part in place so it doesn't move when being soldered. Use something similar, get the pins lined up, and let it set before soldering. Nail polish will probably do the trick.
You should have a very fine tip on your solder iron to do this kind of surface mount stuff.

Installed D2,3,4,5 on main power board, reconnected everything again and at full power with all tubes installed, I'm getting 180vdc@HT pin that got hit earlier. R43(0.0), V1-V6 pins 1&6(0.0), pins 9 to 4(6vac), hum balance pot(24vdc).

[g1]

Installed D2,3,4,5 on main power board, reconnected everything again and at full power with all tubes installed, I'm getting 180vdc@HT pin that got hit earlier. R43(0.0), V1-V6 pins 1&6(0.0), pins 9 to 4(6vac), hum balance pot(24vdc).

You replaced the HT fuse? Is it still good?
0 VDC on both sides of R43?

[ca7922303]

You replaced the HT fuse? Is it still good?
0 VDC on both sides of R43?

Changed fuse before putting it back together and fuse was blown when I just checked it. New fuse and now R43(445/445vdc), hum balance pot is under 10vsc, V1-V6 pins 1 & 6(-1vdc), pin #9 to pin #4(6 vac), full power and all tubes are lit.

[g1]

V1-V6 pins 1 & 6(-1vdc)

R43 is same voltage on both sides so no current is flowing through it. Check it's solder and check for a blown trace between it and R14. Somewhere the trace coming out of R43 is interrupted, and that is why there is no DC on V1-V6 plate pins.

[ca7922303]

R43 is same voltage on both sides so no current is flowing through it. Check it's solder and check for a blown trace between it and R14. Somewhere the trace coming out of R43 is interrupted, and that is why there is no DC on V1-V6 plate pins.

So back side of R43 needed resoldered(I guess from taking the board in and out so much?) now have 0.0 ohms resistance going out toward R14, but no voltage at R43 again(blown HT fuse). Replaced HT Fuse, now @ R43(443/370vdc), V1-V6 pins 1 &6 have voltage. Waiting on PIC from Laney UK. Still need to order a piggyback pushbutton switch for boost/expand. E-switch no longer makes the switch and C-K not responding. Any ideas? Thanks.

[g1]

Did you ask Laney if they had that switch? Getting it shipped at the same time as the PIC would be ideal. If they don't have it you may be out of luck.

If the HT fuse has blown more than once there must be some problem there. Are you using slow-blow type?

[ca7922303]

Did you ask Laney if they had that switch? Getting it shipped at the same time as the PIC would be ideal. If they don't have it you may be out of luck.

If the HT fuse has blown more than once there must be some problem there. Are you using slow-blow type?

Thanks for that idea. Just sent them an email. Have slo blo, is it possible that fuse might have blown with a loose solder joint like I had on the back of R43?