STOP RIGHT THERE he likely DOESNT know what he's doing. I have HAD IT with those who claim to know how to service Counterpoint.
There is a combination of BIAS and DCO and predriver balance which requires 3 multimeters probing 3 things to adjust. He likely over-compensated the DCO pot causing your bias to run hot. You might end up frying your pre-drivers.
Buy 3 cheap multimeters and 3 pairs of cheap clip probes and check the darn thing yourself. Otherwise you will end up sending it to CA for me to repair!!!
Most people see the bias and DCO pots but fail to see the BAL pot (see 1st pic)
1.) hook 1 multimeter across speaker terminal, DCV. Goal is 0
2.) hook 2nd meter across bias test points (IMG_6227) on output driver card, DCV, goal is 50mV AFTER warm up for 10 min
3.) hook 3rd meter across TP1 and TP2 in first pic, goal is 650mV, this should be the same as TP3 and TP4 on motherboard next to TP1 andTP2, if not adjust BAL pot. Depending on your voicing resistors it may be anywhere from 580-750 but the goal is for the 2 phases 1/2 vs 3/4 to be balanced.
Adjust DCO to 0, you will see bias change
adjust bias accordingly. You may need to go back to DCO to tweak once you change bias.
Play safe and go for a LOW bias for starters, say fiddle with DCO and if you see bias shoot up back the hell off.
DO NOT over adjust, if you need to turn over 180 degress something is NOT right. Or you are reading something wrong.
It's a delicate balancing act.
There is a combination of BIAS and DCO and predriver balance which requires 3 multimeters probing 3 things to adjust. He likely over-compensated the DCO pot causing your bias to run hot. You might end up frying your pre-drivers.
Buy 3 cheap multimeters and 3 pairs of cheap clip probes and check the darn thing yourself. Otherwise you will end up sending it to CA for me to repair!!!
Most people see the bias and DCO pots but fail to see the BAL pot (see 1st pic)
1.) hook 1 multimeter across speaker terminal, DCV. Goal is 0
2.) hook 2nd meter across bias test points (IMG_6227) on output driver card, DCV, goal is 50mV AFTER warm up for 10 min
3.) hook 3rd meter across TP1 and TP2 in first pic, goal is 650mV, this should be the same as TP3 and TP4 on motherboard next to TP1 andTP2, if not adjust BAL pot. Depending on your voicing resistors it may be anywhere from 580-750 but the goal is for the 2 phases 1/2 vs 3/4 to be balanced.
Adjust DCO to 0, you will see bias change
adjust bias accordingly. You may need to go back to DCO to tweak once you change bias.
Play safe and go for a LOW bias for starters, say fiddle with DCO and if you see bias shoot up back the hell off.
DO NOT over adjust, if you need to turn over 180 degress something is NOT right. Or you are reading something wrong.
It's a delicate balancing act.
Last edited: