• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Phase Linear 400

how this ? The top TO 92 the first 2 are flat up and the next 2 are flat down .
 

Attachments

  • MVC-007S.jpg
    MVC-007S.jpg
    128.1 KB · Views: 32
MPSA18 ,I knew you going ask that The E voltage is close. On the right side I think Q7 might be shorted .I'm getting 40v on the R34 &R36 junction an 50v at D10& R76. I checked Q7 's orientation and it matches the board .The resistors are correct also . I have to go out . I'll be back
 
the right was 10v and going up when I shut down. The lfet swings from +9v to -10v. Both are L&R are constantly changing .
 
yes on the diodes on C6. 10v on the speaker terminals . I'll check the rails
 
Last edited:
Checking voltages at different stages in the amplifier rarely accomplishes anything due to the fact that it is direct coupled. If q7 is shorted you get 70 volts or so on the output. If offset is in the 10V range with full input voltage then the problem is in the front end. Transistors in backwards will cause this
 
I checked all the transistors and there in correctly according to the directions. I looked up the pin outs and compared them to board the best I could. The voltages are close to spec. with the exception of RQ7
 
At the node of q7 base, cathode of D10, and R76R you should have -.74 volts referenced to ground. At the emitter of Q7 where it joins with R34, R34 you should have --.10 volts.
 
I have an old Sony floppy disk camera here a few more
 

Attachments

  • MVC-002F.jpg
    MVC-002F.jpg
    141.4 KB · Views: 11
  • MVC-003F.jpg
    MVC-003F.jpg
    135.4 KB · Views: 8
You must log in or register to reply here.
Back
Top Bottom