PM-1000 troubleshooting - resistor fried/replaced, just a few questions

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rrandall

New member
Joined
Jun 20, 2015
Messages
2
Hi all,

This is one of my first posts here but I'd like to say thank you right off the bat for all of the old posts on the PM-1000s. Lots of fun researching and reading, building my power supply, chopping up the modules, etc etc. I recapped one and tested it and it sounds great. Recapped the second one today, and made a mistake and now I am trying to figure this out.

- I installed my C6 cap backwards and did not catch it. I powered it up and the 22 ohm resistor right after it in the schematic went up in smoke. Whoops!  :mad:

- I pulled another 22 ohm resistor off of another board, and made sure to measure it with my meter. I installed it and a new C6 cap and powered it all up. Just a bunch of hum, and noise. the low freq knob does introduce more low end to the hum, same with the mids. When I turn the "treble" knob up past a certain point, and my re-wired "echo 2" knob (now serving as my output volume) is up high, a really loud pop followed by a loud hum is introduced.

- If I power the module down, but leave it plugged into the wall, I can then hear signal coming from my mic into my interface (tapping, saying CHECK really loud). It's only when the channel strip is powered on that it is not working.

- I posted a picture showing the resistor that I fried. I am wondering if maybe I also messed up the transistor that is between the C6 Cap and the resistor. If this is the case, am I able to steal one from an unused section of the board and swap them out? If not, and I need to order a new one, I may as well swap them out. What is the best one to use? The one I saw referenced on digitaldrummer.net isn't available at mouser any more.

Thanks for any help! 
Randy

open
 
hey all,

I'm guessing everyone's sick of PM-1000 stuff. I'm bumping just to see if someone knows the answer to one question I have:

Why would I hear signal from my mic when the channel is powered down (but still plugged in to the wall) and only hum and noise when it is turned on?

Thanks, I thought I'd just try this one bump. Appreciate it!
 
No... Do you have an o scope? Do you have a tone generator? If so plug a 1K sine wave into the unit and trace  until you get to that part not working then replace it.
 
Back
Top