Maker Pro
Maker Pro

Heathkit AR-15

mdillah

Dec 12, 2020
1
Joined
Dec 12, 2020
Messages
1
Hi Guys:
I am new to this site and would greatly apricate some help on solving lack of audio from both channels regardless of source. I have provided a schematic.
these are my findings on the flowing voltages from Q201 & Q202, the voltages from Q203-Q207 are ok
Q201- b-.6v, correct, e-0v correct, c-0v should be 8.5v
Q202- b-0v, should be 8.5v, e-0v should be 7.9v, c- 27.7v should be 14.5v
Thanks
Mustapha
 

Attachments

  • Heathkit-AR-15-Sch.pdf
    857.9 KB · Views: 4

bertus

Moderator
Nov 8, 2019
2,644
Joined
Nov 8, 2019
Messages
2,644
Hello,

Here is the extracted amplifier part of the posted schematic:
Heathkit-AR-15-amplifier.png It looks like a C-E short of Q201, as both are at 0 Volts.
Could you take out Q201 and measure the transistor?

Bertus
 

Ylli

Jun 19, 2018
373
Joined
Jun 19, 2018
Messages
373
lack of audio from both channels
Are these incorrect voltages on both channels? Normally a failure of both channels is from something that is common to both channels, like a power supply voltage. A bad Q201 in one channel will not affect the other.
 

Ylli

Jun 19, 2018
373
Joined
Jun 19, 2018
Messages
373
Yeah, I just used "Power Supply" as an example of something that was common to both channels.
 
Top