Repair of a Sheng ya sp-991

One of my amps is not putting out any power. Took it to my tech and after 4 hours he gave up unable to work with a Chinese made shengya without the schematic. Love these amplifiers and do not want to replace them. Does anyone have any experience with the Sheng ya sp-991 repair. It is the monoblock that puts out 100 watts Class A and 300 watts total in A/B configuration. Some say it is identical to the Vincent sp-991 or the Kavent p-220. Live in the
seattle area.
Hi Luked

Have you tried contacting sellers of Shengya gear? Maybe they can steer you in the right direction or give you the schematics or service manual you need.

Here is one e-tailer that has sold Shengya stuff for some time. or

From looking through the A'gon Manufacturer directory here is the contact e-mail I was able to find from there

If you have tried these avenues already with no luck my apologies for the duplicate info.
My suggestion is to contact Ian or Rachel at Grant Fidelity. They are a Sheng Ya dealer and I believe they sold this particular amp in the past.
I contacted Grant audio and they were of no help. Email to Sheng ya provided no response. It is a shame that there are no service centers that are set up to handle an amplifier that is sold world wide under several names.
Luked, I agree; that's very disappointing. I'm quite surprised no one at Grant Fidelity could/would help you. Where did you purchase it? The only other ideas I can come up with are to check with Joe at Pacific Valve who used to be a Sheng Ya dealer (he's in Chicago) or to find out where the Vincent products are serviced here in the states. Both of these are probably longshots, but may be all you have left. Best of luck.
How about this?

Try to call the Vincent Audio Distributor to see if they can help you.

Call toll-free: 1-866-984-0677

Just say you are having issues with the Vincent SP-991 amplifier rather than mentioning ShengYa.