Pelonis Model 6 Signature Series Amplifier

[lazarate54]

Hey Peeps! Has anyone here ever worked on a Pelonis Model 6 Amplifier. Similar to this Chris Pelonis PSS 215A system with amps and crossovers | Reverb (Picture 8). I am looking for any documentation on this amplifier I currently have 1 on my bench with power supply issues on channels 5 & 6.

 

[pucho812]

Any photos?
Whenever I have to work on something without docs I start with testing and taking measurements. Have a dmm? Can go real far here. If you have 4– out of 6 channels working without issue, then should be able to compare and contrast working vs non working.
You have have a blown fuse, it maybe bad capacitors. It maybe way worse.

 

[lazarate54]

Any photos?
Whenever I have to work on something without docs I start with testing and taking measurements. Have a dmm? Can go real far here. If you have 4– out of 6 channels working without issue, then should be able to compare and contrast working vs non working.
You have have a blown fuse, it maybe bad capacitors. It maybe way worse.

Sorry for the late response. I'll attach photos to this response. When I first started working on this amp i had a nasty square wave tone on all 6 channels. I found that the issue was from channels 5-6 but the tone was oscillating thru all 6 channels because they share a common ground. Before i changed anything i made sure that the issue was power related by swapping ribbons from 3-4 and 5-6 and the problem followed.

I discovered that a couple of the diodes (1N4004) had shorted and the thyristors (Q4025L6) on channels 5-6 had gone down. Because of that i was not getting the proper voltage (80vdc) to the filter caps designated to channels 5-6. I was only seeing about 50vdc. After fixing those 2 issues I fired up the amp without plugging in the channel cards to the power supply and I was getting the right voltage across the caps. however when I plugged in the cards channels 5-6 dropped down to 50vdc. Again I swapped ribbons with channels 3-4 and the issue followed so I don't think its a bad audio card.

This has me stumped.

 

[pucho812]

are you sure the caps measure o.k. and have low esr?
Also I didn't quite follow you after you fixed the shorted diodes and replaced the thyristors, what happened? You can connect channels 1-4 and be o.k. but if you did channels 1-2 and 5-6 you have issue, or any combination of adding 5-6 causes a problem?