Kenwood kac 820 repair

[Halse]

kac 820

Thank you.I will buy what is available.

 

[Halse]

can i replace those resistors with 0.25W fusible resistors?

 

[Perry Babin]

Fusible resistors are OK. If you have to repair the amp again, remember that flameproof resistors often show no signs of being burned so you have to check each one with your meter to determine if it has failed. The originals were 1/4 watt.

 

[Halse]

thanks!

 

[Zenekfrompoland]

I live in Poland so on start i sorry for my english, i got problem with the same amplifier KAC-820

Amp rest current when i connect reinforcement starting from 0,8A and getting up to constant 1,5A after some like three minutes (when REM is disconnect), any transistor on opamp board isn't hot, only MOSFET's on main board is warm(voltage on mosfets is the same it for both couples just). When i connect REM, amp turned on and nothing change with current, soft start work, amp working ok, any noise... when i disconnect the -28V and 28V tense from main board to opamp board the amp rest current 170mA on disconnected REM and 250mA on REM connect so i thing something is wrong on opamp board...

I'm not electronic engineer ;/ in service one guy want help my but he need circuit diagram, please help my some1 ;/

 

[Perry Babin]

If the amp is producing clean audio and the only concern is the idle current, the only problem may be that the idle current is set a bit too high. 1.5 amps of current isn't really a problem if it stabilizes there.

 

[Zenekfrompoland]

ok i know what i the problem, in these old amplifier the end of power (mosfets) is still working on power connect, someone who got it before my don't use the amp often and transistors is broken, i change the point of work the mosfets and rest current now is stable 490mA, if i want got the lower current i must take a new transistors, capacitors and check every resistors or replace it too... now amp is connect to relay and its ok, if something going wrong in the future i rebuild it, but now can working, sound is ok, power is probably lower (change point of work MOSFet) but is still satisfactory for my (feed the high freq speakers), thanks for all for help!!! (particularly you Perry)