Fender cyber twin replacement encoder problem

[Klemay83]

I just replaced a broken encoder from an old Fender cyber twin amp. Fender no longer make the part that broke so I found a modern ( unbranded) encoder. The original and the new part are both 4-bit Grey code 16pos encoders.

The new part doesn't seem to be acting the way it should. Instead when you turn it the values jump erratically up , and down, instead of going in increments up or down.

Any ideas with what the issue could be?

[Enzo]

Each switch has four outputs. Get a scope or volt meter on each one and rotate. Does it follow the bit code on the data sheet?

I know the parts list says Gray Code, but is it really? COmpare the switch closure pattern with one of the other original working parts.

Replacing a Gray code with a binary code or vice versa would cause trouble such as you describe.

We need to determine if the part is the correct type, or if the new part is defective, or if the circuit the new part is in also has a problem.

[Klemay83]

Ok , some guessing the bit code was just not the same. So I switched it out and out the original encoder back in. The original encoder worked it was actually the knob shaft in it that had broken.

After about 30 mins the amp showed up with a DSP host error...., never done it before.

Did a factory reset and it was fine for an hour or so , the. The same, DSP error.

Is it possible the other part has some how screwed up the DSP of the amp?