Moogerfooger Noise Troubleshooting

Hello,

I own 5 moogerfoogers. 3 are completely silent when audio passes through. My LPF is VERY noisy and my Murf is kinda noisy.

I have cleaned the contacts with cleaner but the noise persists.

The chassis on these is more metallic than the others, the others seem to be a hybrid metal.

Could this be the case?

I am using the designated power supply.

So please reply with suggestions on the noise solutions.

And/or point me in the direction of the schematic for the LPF and the MURF with typical voltages so I can locate which component might be bad.

Regards
HMPS