Finally My WOPL 400 finished with wattsabundant Help

Joined
Feb 18, 2018
Messages
186
Location
Southern Indiana
Tagline
---6 and 7 days work week, no end in sight
#1
So I was having trouble getting my WOPL 400 up and running.
I contacted Joe for some advice on who I can send the amp to. Joe ran off a list of great people's names I could have went with from here on Phoenix to help me trouble shoot. Decided to contact one of the names that was the closest to me. Don Imlay from wattsabundant is four hours one way. We set a date for me drive the four hours one way to Don's house.

So Saturday 4 January, I met up with Don at his house with my PL 400 8 fin series one. First thing is to go in Don's shop and take the covers off. I already had the control board wires disconnected. Don proceeded to check out the control board out and found some things on the board blown.

When I originaly populated the control board I put a resistor in R14R instead of R41R for Full Comp. I had already corrected that.
In doing so , Q2 TO-200 MJE15033G Transistor, D81 Zener Diode, small Diode on the right side was blown.
Good thing Don has a lot of these items in his shop. Don replaced the blown parts. Got the control board back in and I wired it up.
Got the amp hooked up to Variac and some other scope equipment Don has. Almost instantly R27R started to cook and smoke. Got it powered off quickly.
Right side I had the 5R and 4R wired back words. Got those wires in the correct connections.
Don was not concerned about the R27R, so continued to power the amp back up once again. Got the amp Bias set and DC looked good according to Don's
equipment. So we installed one of Don's DC Protect relay's, I did not install one yet. Don made sure and tested the DC Protect relay worked before going in the amp. Works great in the amp, I like it. Everyone should have one of these DC Protection relay's in there amplifiers. wattsabundant DC relay are top of the line.
After about five hours at Don's house, my amp is now a fully working WOPL 400. For a cup of tea, well worth it.

If you ever get a chance to meet Don, your going meet a real knowledgeable gentleman.
 

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Joined
Feb 18, 2018
Messages
186
Location
Southern Indiana
Tagline
---6 and 7 days work week, no end in sight
#3
The White Oak light board has soft white LED's I thought were still pretty bright. Got some amber color film and put the film between the meter bezels and meters, I like that look. Most go with a blue, just wanted to be different. The rack handles I got off ebayer "ohmbob". Amp sounds great. Frist WOPL I ever listened to.
 
Joined
Feb 18, 2018
Messages
186
Location
Southern Indiana
Tagline
---6 and 7 days work week, no end in sight
#6
The White Oak up grades Joe sells are top of the line. Can't beat it. The build was fun. I'm just not good at trouble shooting when I goof something up.
The WOPL 400 I sounds awesome. I play the amp every day. If I do another WOPL, I know will have to happen with my PL 700 II, the control
board, backplanes and Cylon meters will have to be already assembled.
 
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wattsabundant

Chief Journeyman
Joined
Apr 26, 2011
Messages
842
Location
Central Ohio
#7
A couple comments: Ron had already determined the negative 15 volt supply had failed. I started by connecting a variable power supply at the regulator input with the current limit set to minimum. The power supply immediately went in to current limit which suggested that Q2 failed. Further testing rvealed a shorted 20 volt zener. I didn't have the exact replacement parts. I used 2 x 10 volt zeners in series. I used an MJE 15029 in place of the MJE15033. Although R27 did smoke, it still measured within spec. I left it in so that we could continue. The voltage rating of the MJE15029 is marginal for the application. When we finished I urged Ron to order the correct parts for long term reliability.
 
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