FPALB
Well-known member
Just putting up my findings for anybody else who may have to repair one of these in the future as Classe has been out of business for some time.
First tip: Lift with your legs...it's VERY heavy
The owner came in and let me know the unit stopped powering on.
In a separate post I was requesting schematics, but found none - Classe was actually responsive and gave me what schematics they had on file, which were hardly helpful at all. Ill attach them here also just in case someone needs them.
I opened it up and found that the system has 2 completely separate power supplies - a low voltage supply to make power standby capabilities possible, and a high voltage for the actual amplification circuits.
The bulk of the front end is made up of 3 transformers (the big one which is the amplification mains transformer, the top mounted mains transformer, which originally says "classe" on it, which is for low power stuff like relays, and the tiny chassis mounted mains transformer which is for the standby circuit), mains filtering for all 3 separate amp blocks, and high power relays.
The circuit at fault here was actually the low power circuit. I can't be sure exactly what happened as this circuit is fairly basic, but my only guess is that the rectifier shorted out and blew out the top mounted transformer and luckily blew the fuse labeled "F1" . I freaked out at this point because I thought it was game over, but upon inspection of the PCB this transformer has only 1 secondary and some international option on the primary, so..its nothing special. This transformer feeds a rectifier, which was also blown, and then fed a 12v regulator (there was also some filter caps and they measured great). So luckily I had a 12v secondary toroidal transformer that I mounted (luckily fit perfectly) and replaced the rectifier and everything popped back on and so far is working great. As you can imagine this is the abridged version of my repair story.
Hope this helps save another tech some time.
All the best.
Jon
First tip: Lift with your legs...it's VERY heavy
The owner came in and let me know the unit stopped powering on.
In a separate post I was requesting schematics, but found none - Classe was actually responsive and gave me what schematics they had on file, which were hardly helpful at all. Ill attach them here also just in case someone needs them.
I opened it up and found that the system has 2 completely separate power supplies - a low voltage supply to make power standby capabilities possible, and a high voltage for the actual amplification circuits.
The bulk of the front end is made up of 3 transformers (the big one which is the amplification mains transformer, the top mounted mains transformer, which originally says "classe" on it, which is for low power stuff like relays, and the tiny chassis mounted mains transformer which is for the standby circuit), mains filtering for all 3 separate amp blocks, and high power relays.
The circuit at fault here was actually the low power circuit. I can't be sure exactly what happened as this circuit is fairly basic, but my only guess is that the rectifier shorted out and blew out the top mounted transformer and luckily blew the fuse labeled "F1" . I freaked out at this point because I thought it was game over, but upon inspection of the PCB this transformer has only 1 secondary and some international option on the primary, so..its nothing special. This transformer feeds a rectifier, which was also blown, and then fed a 12v regulator (there was also some filter caps and they measured great). So luckily I had a 12v secondary toroidal transformer that I mounted (luckily fit perfectly) and replaced the rectifier and everything popped back on and so far is working great. As you can imagine this is the abridged version of my repair story.
Hope this helps save another tech some time.
All the best.
Jon
