On Wednesday, April 3, 2013 10:18:02 AM UTC-5, Naor wrote:
responding to

http://www.electrondepot.com/repair/...er-145554-.htm , Naor

wrote:

billdegener wrote:



On Saturday, March 23, 2013 11:28:59 PM UTC-5, WLD_Bill wrote:

Pressed power button, unit powers off after 3 seconds.







Bypassed protection mode by holding "Effect" &

"Night" buttons while



pressing power button.



Unit displayed the code "PRD PRT 210"







Manual states as follows....







When there is a history of protection function due to abnormal DC



output







PRD PRT:xxx (xxx AD value when the protection function is working)









Cause: DC output of the power amplifier is abnormal.







Supplementary information:



The protection function worked due to a DC voltage appearing at

the



speaker terminal.



A cause could be a defect in the amplifier.



If the power is turned on with the abnormality unsolved, the



protection function works in about 3 seconds to turn



off the power.







Ideas where to start? LOL.... DC voltage appearing at the speaker





terminal? None showed



up with a DVM



Checked Q119 (2n5551c) with dvm. I checked ok.





Hi I have the same problem with my receiver, did you managed to fix it?



Thanks

Did you check the voltage outputs of the amp of the (7) protection circuit resistors? They are the white large cement (ceramic) type.

Download the datasheet and it will demystify the the circuit and how it works.
I found it quite interesting, especially the 8 bit code to the MCU stuff that Mark Z explained. I haven't delved much into that yet (just curious) The overvoltage protection circuit is neat how it puts the amps into standby mode, etc..