Phase Linear 200 rebuild

Excessive Dc offset usually comes from Q1, Q2, Q3, Q4

Watching the unloaded amplifier output on the scope as I bring it up on the variac, I get increasing +DC with respect to return. If I bring the AC up high enough, I start seeing +DC on the scope channel where I am monitoring input. It is occurring on both channels.
 
It does not smoke. I have to wait for my loads to arrive for a full up test. I have triggered the protection circuit a couple of times and it comes right back after a delay. I tried to upload video, but it failed, sigh.
 

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It does not smoke. I have to wait for my loads to arrive for a full up test. I have triggered the protection circuit a couple of times and it comes right back after a delay. I tried to upload video, but it failed, sigh.

Try dragging your video clip over Dan. That usually works.
 
Hmm. It appears that I have failed to upload the video once again . I just tried again (via dragging it into a message composition window). I saw an "Oops! We ran into some problems." dialog after the transfer completes. I must have missed seeing that last time - Ugh.
 
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I’m setting out to rebuild the 200b sitting on my self for 10 years. Many have stated the poor performance of the series one and b , the series two is compatible with a series ll 400 and 700 in basic design . My goal is a tweeter amp
well this one not a series ll so I’m gutting it and fitting a rev E board I have. This is just right size to fit in.
it’s going to be full complimentary with addition of extra output to drive the mj21195/96 pairs

gathering parts for December build. And one idea is the vu meters that I have. No idea what they came out of as they are 113 x82 mm just smaller that the 400 and 700b

should be strat forward build

thing that may need addressing are resistors in protection circuit and possibly power supply section21D8CF48-5460-4952-8695-5C1884159BD6.jpegF325FF46-5FE0-44EE-A458-E7B577BF9D7E.jpeg705454FC-9795-4DE0-8ABE-6BACA8D35AAB.jpegE2705E41-CBBF-474C-889C-259CFA0CB147.jpegA6381B15-1AAB-4B26-BEBE-938E163BF2F7.jpeg1E5C47E8-B185-4592-945D-8952EA6D81F4.jpeg
 
This amp has delay on with speaker protection
the protection circuit is a little curious as the main power output to the board that I senses has different values from left to right channel R57 and R58 on b and r1 and r2 in series ll schematic attachedFAF91515-69D2-4CAD-8C72-9A6DFBA96559.png36E8AE46-4022-44EB-8FFC-43F2702B3BA5.png

the other thing will be thermal bias control added via bias transistors added
 

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The PL200 S2 is a sweet sounding amp, not a lot of power but very pleasing sound. As Ed said on the S1 versions.


Anybody found any newer info on updating the PL200B and the PL200II? I'm heading to Chicago area to deliver some gear and pick up some gear for repairs. He's got 2 of the 200's (a series II and the 200B) and they need some TLC and I'm upgrading everything in both amps, caps, transistors, Outputs, speaker jacks (they need to be 5 way and not spring loaded junk), wiring and it will get a few other items. So if you see any good threads on replacement parts, let me know. I'm also picking up a Sansui 5330 cassette deck and a Tascam 122MK III both for services, belts, missing buttons/knobs. I'm gonna spend his money for sure. I think I have another piece or 2.
 
122 MkIII needs the motor board caps replaced. Sam does it no matter what as they are a known failure point. SMDs I believe. Otherwise, clean and lube, then electrical set up/base bias for ONE tape- the other two reference the one, so find out his favorite tape and set base bias for that...
 
122 MkIII needs the motor board caps replaced. Sam does it no matter what as they are a known failure point. SMDs I believe. Otherwise, clean and lube, then electrical set up/base bias for ONE tape- the other two reference the one, so find out his favorite tape and set base bias for that...


If the manual is worth a shit, unlike the sansewer Integrated I just reworked, the manual tells you to adjust VR4 for xxx and there isn't a VR4. I'll hit the manual and do what I can.
 
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