sansuibutch
Super Member
Gotchya. I measured those and here's the results
Left channel
B. -.03
E. .03
C. -.605
Right channel
B. .143
E. .00
C. -.725
I thought I would understand these better but there all over the place
Ba2000 right channel sounds very distorted
- Thread starter sansuibutch
- Start date
Gotchya. I measured those and here's the results
Left channel
B. -.03
E. .03
C. -.605
Right channel
B. .143
E. .00
C. -.725
I thought I would understand these better but there all over the place
Moving along, voltages are missing off left channel so ---
First check blue circled right channel then left channel
Then green circled right channel and left channel (may be a couple out of circle)
Going to be on the road the next couple of days perhaps Hyperion will continue for me?
-Lee
First check blue circled right channel then left channel
Then green circled right channel and left channel (may be a couple out of circle)
Going to be on the road the next couple of days perhaps Hyperion will continue for me?
-Lee
sansuibutch
Super Member
Thank you both . I appreciate it. I'm going to measure the voltage at them very shortly.
sansuibutch
Super Member
These are the measurements from the blue circled ones.
Right channel
B -57.6v
E -58.2v
C - 1.496v
Left channel
B 57.9v
E 58.4v
C 2.18v
It looks to me like the voltage drop is between the last two measured on the left channel. I notice there is more voltage on b,e and c on the left channel. Is that because its not traveling to the other transistor?
Right channel
B -57.6v
E -58.2v
C - 1.496v
Left channel
B 57.9v
E 58.4v
C 2.18v
It looks to me like the voltage drop is between the last two measured on the left channel. I notice there is more voltage on b,e and c on the left channel. Is that because its not traveling to the other transistor?
sansuibutch
Super Member
Tr21 and tr07
TR21 & TR07 - They both look OK - sorry I am going to have to go over some stuff already covered.
If these readings were for TR15/17 or TR16/18 (or a combination) - if so, these aren't all that important at the moment. (please indicate the TR numbers for these).
Does one channel work and if so which?
If these readings were for TR15/17 or TR16/18 (or a combination) - if so, these aren't all that important at the moment. (please indicate the TR numbers for these).
Does one channel work and if so which?
sansuibutch
Super Member
The readings you posted are from tr17 and tr18 and the right channel is the working channel
Those TR numbers are from one channel - but noted below as being from each channel
Please clarify.
sansuibutch
Super Member
Right channel
B -57.6v
E -58.2v
C - 1.496v
Left channel
B 57.9v
E 58.4v
C 2.18v
These are from tr07 and tr12.
Tr07 and Tr21 are both left channel. I was thinking between these was where I was loosing voltage and might need to be disregarded. Not sure
sansuibutch
Super Member
I erased this response and used the reply option.
Last edited:
sansuibutch
Super Member
sansuibutch
Super Member
Tr13
C 1.943v
E -1.253v
Tr14
C 1.774v
E -1.48v
I turned them both while measuring and the voltage seems to increase pretty equally on both.
sansuibutch
Super Member
I did ohm out the trimmers also and they tested good
OK, I hope you have a set of hook tip probes? - I want you to measure the voltage between the bases of TR19 and TR21 - (both in the left channel) - the safest place is to hook onto R39 (top end) and R41 (bottom end) and try that trimmer adjustment again - remember you are adjusting the Bias - so be careful - remember to return the good channel bias (R) to where it was before the adjustment from post #256.
I usually power off to connect probes for this kind of adjustment - just gives you a chance to get them in exactly the right place without fear of shorting anything.
I usually power off to connect probes for this kind of adjustment - just gives you a chance to get them in exactly the right place without fear of shorting anything.
sansuibutch
Super Member
OK, I hope you have a set of hook tip probes? - I want you to measure the voltage between the bases of TR19 and TR21 - (both in the left channel) - the safest place is to hook onto R39 (top end) and R41 (bottom end) and try that trimmer adjustment again - remember you are adjusting the Bias - so be careful - remember to return the good channel bias (R) to where it was before the adjustment from post #256.
I usually power off to connect probes for this kind of adjustment - just gives you a chance to get them in exactly the right place without fear of shorting anything.
With the trimmer all the way down it reads -1.78v. I spun it all most all the way up and it was -1.95v
OK - it looks like the bias transistor isn't turning on, so it is either faulty or installed incorrectly, OR R37 (47 ohm), R39 (1K), or R41 (1K), are open or the wrong value. (also possible R29 5.6K, R31 1K). What do you have for a bias transistor? (schematic says 2SC1904) - test it, and the resistors - change anything that is out of spec (lift the resistors to be sure) - then try measuring that voltage again - you should be able to vary it a lot more.
