Author Topic: Denon AVR-x2000 fault  (Read 1425 times)

0 Members and 1 Guest are viewing this topic.

Offline cpposteveTopic starter

  • Regular Contributor
  • *
  • Posts: 58
  • Country: gb
Denon AVR-x2000 fault
« on: January 24, 2020, 01:07:44 am »
Hi all.

after a bit of help here.

i bought this 7ch amp broke. and having a bit of a mare trying to fix it.
i fixed the original fault with the help of the service manual where one of the ksa992f transistors went short circuit and kept blowing resistors.
on powering it back up it now doesnt cut off after 2 seconds and flash red. but instead now it starts to blow the big transistors on the board.

in the picture  you will see two 22r resistors marked in pink. when powering the amp up it sits there happy for a while, then after about 5-10 seconds these resistors start to glow and pop, taking out the large transistors marked in orange. and while on its travels it takes out part of the resistor network in blue.

its really bugging me as looking at the schematic it would apear to me there is a short on the 2sc3694 (Q445).
but i have tested all 7 of these and they are working fine.

amps are not my forte so any help in diagnosing this would be a great help.

cheers

steve
 

Offline mzacharias

  • Frequent Contributor
  • **
  • Posts: 710
  • Country: us
Re: Denon AVR-x2000 fault
« Reply #1 on: January 25, 2020, 01:09:56 am »
Bias transistor 2SC3964, output transistors, diode string associated with the bases of the output transistors (probably at least two bad) all four emitter resistors. Check the remaining transistors and there may be burned resistors associated with them. If so replace those transistors and any such resistors.

Check carefully for potential bad solder connections with the outputs to the main amp board.
 

Offline cpposteveTopic starter

  • Regular Contributor
  • *
  • Posts: 58
  • Country: gb
Re: Denon AVR-x2000 fault
« Reply #2 on: January 25, 2020, 08:38:48 pm »
cheers for your reply.

the bias transistor all seem fine.
the diode string is not fitted to this model.
the emittor resistors are burning up along with the output transistors, which is the issue im having. i cant fathem out why they randomly popping when switching on,
i have checked most of the other associated resistors and all seem fine. ive also checked all of the voltage regs and they all seem good too. im really stumped

steve
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf