Halfway through fixing this C Audio SR606. Looks like it's an early version with relays on the driver boards and copper heatsinks. . This one was completely dead when it arrived....
Found out there was a bad fuse holder in the back. Temporary fix by bypassing it and relying on fuse in plug .
Powered up on dim bulb... Slowly ramped up till the soft start released. This was a bit hit and miss as second attempt it went dead again... Found a power switch wire bad joint. Then I finally got it fired up.
It then goes straight into protection.. 75v DC on channel B. Very low DC offset on the other side. Still on dim bulb so lower voltage. I can hear two relays click. Sounds like one is the soft start and the other from the good channel.
Removed the power wires to the MOSFETs and pulled out drive board. Measured driver board output and still got huge DC. So fault on this board . Found at least 6 small signal transistors shorted. BF422/23s. I'm hoping there is no shorts on the MOSFETs. They did test fine with a quick test and fuse wire not blown. .
These boards do not have any component markings on the PCB at all.
I used a white pen to mark the shorted transistors
If I don't get this repaired this still plenty of spares for my other C Audio amplifiers.
Found out there was a bad fuse holder in the back. Temporary fix by bypassing it and relying on fuse in plug .
Powered up on dim bulb... Slowly ramped up till the soft start released. This was a bit hit and miss as second attempt it went dead again... Found a power switch wire bad joint. Then I finally got it fired up.
It then goes straight into protection.. 75v DC on channel B. Very low DC offset on the other side. Still on dim bulb so lower voltage. I can hear two relays click. Sounds like one is the soft start and the other from the good channel.
Removed the power wires to the MOSFETs and pulled out drive board. Measured driver board output and still got huge DC. So fault on this board . Found at least 6 small signal transistors shorted. BF422/23s. I'm hoping there is no shorts on the MOSFETs. They did test fine with a quick test and fuse wire not blown. .
These boards do not have any component markings on the PCB at all.
I used a white pen to mark the shorted transistors
If I don't get this repaired this still plenty of spares for my other C Audio amplifiers.
