- Joined
- Jan 14, 2011
- Messages
- 75,404
- Location
- Gillette, Wyo.
- Tagline
- Halfbiass...Electron Herder and Backass Woof
I don't know either....
So looking over my work I have now realized that I made a mistake when replacing C2 and C9 (rated at 22uf 10V) and substituted 2.2uf 35V in its place. Don't know if that could be causing the loud hum (which appears to be 60 Hz) but it obviously needs to be corrected. Was using a bad pdf of the service manual and was able to get my hands on a better resolution one and realized there was not dot between the 2's. Waiting for the parts to show up as the leads on the old parts are too short now to put back in
Hopefully this rectifies the situation and I can move forward cleaning this unit up. Still waiting to get some quality time with the 400 now seeing as I have pretty much all the parts and just need some time to start the tear down.
So I ended up not having a good ground connection between the board and the chasis. I had installed the center screw holding the board and not the two outside ones when I was testing the unit. Didn't realize at the time they were the actual grounding screws. Now it runs great. Next step is to clean up all the rca jacks and front pots then install the new replacement op amp with the brown dog adapter.
Thanks again for helping me narrow down the issue and learn a few things especially the basic stuff.
Love the pic of the old cornbinder scout!
Still working slow and steady on the phase linear 400. Was browsing the threads and found some information on latch up tendency and placing diodes across C6 to help fix this. I think I have a handle on why the diodes would be beneficial but I was unclear on if it is something that should be installed automatically or only if I have issues. Also wasn't sure which diode would be appropriate to install
Thanks
You desoldered the swirch totally?