Just replaced the output transistors. Looking for a procedure to set up the trimmer resistors VR202, VR201. I believe these adjustments are for DC bias. Could you provide this information?
Thanks in advance for your help.
Comments
This site helps you to save the Earth from electronic waste!
Hello Cello,
Yes,they are the bias adjustment trimmers.
Service manual
tj
0
Thank you tj. Unfortunately the service manual does not provide the adjustments values. Would you suggest what the values should be?
Thank you for the help.
0
Hello,
30-40 mA.
0
Thanks for the reply torokj.
Would you be so kind to tell me if the 30-40ma are calculated or you got this info from the service manual. I cannot see this information on the service manual that is on line. Also, what would be the procedure to adjust VR-202,VR-201. Where to connect the ammeter? I assume with a speaker load and no signal?
Best regards
cello
0
Hello,
I calculated this data (+-27 V power supply,old school power amp ) Connect the ammeter to the power supply positive ,and the power amp positive (The easiest way desoldering the collector pin of the Q209 (after Q210)
With speaker (or dummy load) and zero volume.
Good luck!
Bias tutorial
tj
0
Thank You torokj. Much appreciated.
1