Crate FXT65 DSP Troubleshoot?

[misterc57]

Picked up this amp but it did not have the original 3 button foot switch. I want to see if the DSP is working.

There is a mono 1/4 jack in the back for DSP toggling. Next to it is a TRS jack for channel / gain switching.

I inserted a standard one button foot switch but I am unable to get the DSP to function. The tip of this jack does toggle to ground when I press the foot switch button.

The DSP "level" mix knob is turned up.

I am wondering if there is a problem with the DSP circuit. TP16 has 10 VDC and I see 9.6 VDC up the wire #4 to the DSP board.

I have attached the schematic.

Thank you for your help and suggestions.

MC

crate_fxt-65_fxt-120_07s194_sch.pdf

[g1]

Is your test footswitch a latching type? Have you tried a momentary? Or just plug in a cord and briefly touch the tip at the open end to the shell at the amp end.

[Jazz P Bass]

Do you have a signal at IC 5 pin 1.
The footswitch should toggle that on & off (Q28 E).
If you have signal, then that gets sent to the DSP board & returns at J10/ pin 1 as a DSP'd signal.

[misterc57]

The latching footswitch is toggling the signal feeding the DSP board. However there is no signal returned from the DSP board.

[Jazz P Bass]

This may or may not be the same DSP schematic.

[misterc57]

This is the board I have. Crate DSP board 06-885-01

[g1]

This may or may not be the same DSP schematic.

Here is revision V5 of same.