Crate FXT 120 switching jack problem

[groovyfingers]

I will be replacing three switching jacks on this amp. The input on the front, Channel/Gain Select and DSP on the rear. I'm assuming these three are the same TS type switching jacks. Does anyone have a part number for this jack? A seller has some but for a Marshall and I don't know how similar these switching jacks can be. I guess I could call Crate? Thanks

[Enzo]

Look at the jacks, do they have two contacts or three? The three ways are TRS jacks.


These are your basic Cliff type jacks, also made by Neutrik/Reann, and others.

[groovyfingers]

These three jacks take a TS cable connector, a guitar cable end. So they should be two contact, not three. I will search for Cliff type jack along with the make, thanks Enzo.

Look at the jacks, do they have two contacts or three? The three ways are TRS jacks.


These are your basic Cliff type jacks, also made by Neutrik/Reann, and others.

[Enzo]

Channel/Gain footswitch jack is TRS. Tip is channel and ring is gain, I think.

The Insert jack is a TRS. RIng is send, tip is return, I think.

[groovyfingers]

Yes the channel/gain select is TRS along with the insert. Only going to replace the input, and leave the little board that has the channel/gain select and DSP alone. I ordered three TS jacks and I'll use the nuts off two of them to mount that small board that was loose inside the chassis. The input jack was pulled clean off the main circuit board! When I get the main board out and on my work bench I'll see what damage was done tearing that input plug off. Hopefully not too much.

[groovyfingers]

Enzo, will it be fine to just reinstall the board and tighten up the heat sink with what grease is left on it? Or do you apply additional?

[Enzo]

I always have a tube of heat grease next to me on the bench, so if I take apart something, I generally put a new stripe of white goo along the surface.

[groovyfingers]

K will have to get some. Thanks.

[groovyfingers]

Replaced input jack, reflowed solder on all pots, heat sink grease on heat sink, reassembled circuit board in chassis, and installed chassis into cabinet. Powered up and clean channel not working right, volume pot goes from no sound to sound that stays at a fixed volume no matter what position the pot is in. Nowhere near the volume a 120 watt amp should have. Rats. On a positive note, the overdrive channel works fine. Goes from low to high with volume galore. Sprayed Deoxit in both the insert and aux speaker jacks and worked them by inserting and removing a 1/4" guitar cable end just to clean them. The three switch pedal and cable works the channel switching and DSP just fine, although the LED indicator for when the DSP is engaged is dim, not bright like the Channel/Gain LED's. What to do next in your opinion?

[Enzo]

Sounds offhand like that volume control is open or has a broken connection.

[groovyfingers]

Will search for testing a potentiometer like I have to verify proper operation and connection thanks.

[Jazz P Bass]

Search what?

A potentiometer is nothing short of a resistor (the two outside legs) with a variable leg that moves up & down that resistance.

As to a broken connection, that can be verified with an ohmmeter also.