Mark goes at it again... just bought a PL700/II!

mlucitt

Veteran and General Yakker
Joined
Jun 24, 2011
Messages
3,339
Location
Jacksonville, FL
Great video Mark. Your description of the power switch loop/thermoswitch black AC wire got me to thinking. I might run the fan AC jack black wire to the closest thermoswitch "hot" terminal rather than back to the transformer terminal strip. That way, if the amp overheats and shuts down due to a thermoswitch opening, the fan AC jack still has power, so the fan stays on to help cool the amp. Plus, it's a shorter run for that black AC wire.

Thoughts?
 

MarkWComer

Veteran and General Yakker
Joined
Nov 1, 2014
Messages
3,198
Location
Gaston, SC
Tagline
Victim of the record bug since age five
Great video Mark. Your description of the power switch loop/thermoswitch black AC wire got me to thinking. I might run the fan AC jack black wire to the closest thermoswitch "hot" terminal rather than back to the transformer terminal strip. That way, if the amp overheats and shuts down due to a thermoswitch opening, the fan AC jack still has power, so the fan stays on to help cool the amp. Plus, it's a shorter run for that black AC wire.

Thoughts?
The fan outlet would be unswitched. If you want to do that, just leapfrog directly from AC input as I did with the neutral wire. The original wiring had the fan outlet switched and I wanted to keep it that way, but nothing says you can’t leave it live. Some have even omitted that outlet altogether.

My big issue is that I wanted the thermal cutoffs after the switch, not between them (also according to the original wiring).
 

MarkWComer

Veteran and General Yakker
Joined
Nov 1, 2014
Messages
3,198
Location
Gaston, SC
Tagline
Victim of the record bug since age five
Great video Mark.
I’m not satisfied with it. Bad continuity, choppy editing, and I restarted the wiring part twice because I didn’t have the grade of wire I wanted. I tried to cover too much in the original video and tangled how I wanted to make the presentation. Short videos hold attention better, smaller chunks of procedure allow better detail. Probably the worst video I made so far.

BAD error, too- I had the AC to the LED meters coming directly from the rectifier instead of the 6-6-12 transformer winding.

I meant to ask- who on Phoenix discovered my first series on the 400? I only meant those to be home movies, and production on those were crappy, too. Regardless, one of our members with limited internet access requested that series on a disc, mailed it out just now.
 
Last edited:

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
Heck Mark your doing at least three jobs at once, the build , the video, and the production, don't be hard on yourself cause what your doing is very much appreciated by us. Continue on and we'll be there. Thank you!
 
Last edited:

MarkWComer

Veteran and General Yakker
Joined
Nov 1, 2014
Messages
3,198
Location
Gaston, SC
Tagline
Victim of the record bug since age five
Installed second row of outputs, getting -.6vdc at the +15 test point. What does this indicate?
All other TPs read correctly. Bad transistor?
L channel...
 
Last edited:

MarkWComer

Veteran and General Yakker
Joined
Nov 1, 2014
Messages
3,198
Location
Gaston, SC
Tagline
Victim of the record bug since age five
First row produced good results?
First row was fine.
After second row, measured 122vdc (on variac/DBT) between filter caps far negative to far positive, 122vdc on pads 11/12 of left control circuit, 60vdc on pads 11/12 of right control circuit. (Sorry, the problem is on the R, not L).
 
Top