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Help please, sansui R30

J

Jerry Hawtho

New Member
New to solid state, use to tube radios.
Problems
1 flunked the dim bulb test. Replace rectifier and two input caps.
2 left channel has +24v at speaker output.
Removed 2 output transistors. No help.
3. TR23,noted to have a broken lead (2SC1845). Removed
Voltages on "socket " -38B, -38E, +37C.
4. R161 2.2K off TR23 Smoked and open, + 34V on one side and--34 on the other!
5. C163, 33mfd shows +34v on both sides.
Other than trying to find the resistor and Tr23, where should I go from here?
Thanks for any help.
Jerry
 
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The schematic has voltages at different points in the amp circuit. Look to see where the voltage goes off track.

- Pete
 
The service manual shows only 2 voltages for the amplifier section, plus and minus 34V. I tried attaching a screen shot of the amplifier circuit but it was unreadable. Hoping for a little guidance based on my observations.
Thanks, Jerry
 
kwayde said:
View attachment 3811379
Click to expand...
Thank you for that, I was working on the other channels schematic as the part ID info matches the channel I'm having problems on. My first venture into solid state stuff, use to tube radios.
I have the AM/FM Working on one channel but I'm a bit lost on the other. I have listed some voltages reading based on the removal of the output transistors and TR24 (number on you posted schematic).
I need some guidance where to go next please.
 
To add more confusion on.my part some voltages readings:
Socket readings, transistors removed.
TR 23. E-37V C+37V B-37V
TR21. E+37V. C-37V. B-37V
TR19. E+32V. C+36V B+36V

IN "socket readings:

TRs 13 and 17. -36V for BC&E
TR 15 +36V for BC&E

Sure would be nice to get some guidance on this. As indicated I'm new at this solid state stuff. All measurements were from chassis for ground.
Thanks for any suggestions, I'm lost!
Also as mentioned earlier, R161 a 2.2K resistors blew open, having a large positive voltage on one side and a large negative on the other.
 
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Bringing the subject up again, I had it working then it died in the same channel. Replaced all the transistors and the following are my voltages readings.

B. E. C
TR 22. --36 +36. -36
TR 20. +36. +36. +36
TR 24. -29. -36. +28
TR 18. -36. -38. -32
TR 14. -36. -36. -36
TT 16. -28. +36. ÷36

I hope with these voltages some could provide a little guidance on what to do next.
Thanks, Jerry
 
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