Laney TT50H No Outout

[g1]

First make sure it is stuck down to the board with pins lined up using some kind of glue or fixative like the original had (red stuff). You need a fine tip on your solder iron. If you don't have one, in a pinch you can grind it down. Make sure the tip is coated with fresh solder for quickest heat transfer. Solder should be fairly fine type as well.
Get on and off the chip as fast as possible. Allow chip to cool between soldering each pin, and stagger the order of the soldering so you aren't doing pins next to each other, which also helps prevent overheating.

[ca7922303]

Yes, both parts are 'D' suffix, so either one will work. D suffix indicates SOIC-14 package.

I've got U2 now(2 of them), can you tell me any tricks to soldering one this small with 14 legs? Thanks.

[g1]

Yes, both parts are 'D' suffix, so either one will work. D suffix indicates SOIC-14 package.

[ca7922303]

Previous U2:. 771-74HCT08D-T

[g1]

Depends which one you used before. Was the other one a D suffix? Or AD or PW? They are different packages so one will fit and one won't.
If the other one was 74HCT08D then this one will work.

[ca7922303]

Yes it's possible. Aside from overheating, it could have been damaged by the ribbon cable going to the wrong socket at other end, or if something funny happened at the footswitch connector.

Previous U2 I ordered from mouser(74hct08) is out of stock until 9/22. Can you tell if this one will work in its place? Thanks. 74HCT08D-Q100,118 Datasheet (PDF)

[g1]

Yes it's possible. Aside from overheating, it could have been damaged by the ribbon cable going to the wrong socket at other end, or if something funny happened at the footswitch connector.

[ca7922303]

Lifted U2 pin 5, R3 now(10k ohms). I'll order at least two(2) this time. Thanks.

Also, channel was working, can overheating cause it to go bad over a short period of time like this one did?

[ca7922303]

Such small chips are easy to overheat when replacing. If the R3 reading goes to 10K when pin5 of U2 is lifted, you will need to replace it again.

Lifted U2 pin 5, R3 now(10k ohms). I'll order at least two(2) this time. Thanks.

[g1]

Such small chips are easy to overheat when replacing. If the R3 reading goes to 10K when pin5 of U2 is lifted, you will need to replace it again.

[ca7922303]

Yes, U2 was replaced.

[g1]

Back around New Years I had said a couple times that U2 needed to be replaced. You had the old one removed, did you replace it with a new part?

[ca7922303]

What resistance readings do R2 and R4 give?
Wasn't one of those replaced before, which one?

If R2 and R4 give 10K readings, then de-solder U2 pin5 and recheck R3 resistance.

R13 I believe without looking(at work now) was the only surface mount resistor that was replaced.

[ca7922303]

R2/R4(10k ohms). Will desolder R3 this evening when off work. Thanks.

Meant to write desolder U2 pin 5.

[ca7922303]

What resistance readings do R2 and R4 give?
Wasn't one of those replaced before, which one?

If R2 and R4 give 10K readings, then de-solder U2 pin5 and recheck R3 resistance.

R2/R4(10k ohms). Will desolder R3 this evening when off work. Thanks.