I have a Trio KA-8700 japanese version of kenwood KA-801 in Europe /America.
Curretnly i am trying to replace all electrolyte caps in all boards(Power amp except 4 10.000uF/63V i can not find, pre amp and tone control ).
After replacing & re-assembly i powered it up in order to adjust dc offset, bias current etc.
The amp relay clicks after 5-6 seconds but i see smokes from the transistor D313V/B507V (regulation of the pre-amp board) the heatsink is very hot so i turn off the amp and look carefully all caps in amp for correct value & direction, any short wires etc....
Powered again and smoke comes again. So i must shut off it immediately and now look for the reasons.
I want to look at schematics/service of this amp but the service manual download from Hifiengine, Audiokarma... seem to be not fully or has very bad quality - unable to read for my repairing purposes.
Has someone a schematics from this amp kenwood KA-801 i would like to thank in advance.
Further i want to know also how can i substitute these D-313V-AL/B507V-Al if they are burnt?
PS:
By measuring: R77/R78: 47ohm,
R79/801,3K,
R81/82: 1,2K
all is as stated in the service manual
The power supply to the pre amp i get B +/_ appr. 58 V. is it normal or?
My knowledges in electronics is limited please help me for easy understanding why these transistors get burning if anyone can and what i must check etc.-
thank you!
Curretnly i am trying to replace all electrolyte caps in all boards(Power amp except 4 10.000uF/63V i can not find, pre amp and tone control ).
After replacing & re-assembly i powered it up in order to adjust dc offset, bias current etc.
The amp relay clicks after 5-6 seconds but i see smokes from the transistor D313V/B507V (regulation of the pre-amp board) the heatsink is very hot so i turn off the amp and look carefully all caps in amp for correct value & direction, any short wires etc....
Powered again and smoke comes again. So i must shut off it immediately and now look for the reasons.
I want to look at schematics/service of this amp but the service manual download from Hifiengine, Audiokarma... seem to be not fully or has very bad quality - unable to read for my repairing purposes.
Has someone a schematics from this amp kenwood KA-801 i would like to thank in advance.
Further i want to know also how can i substitute these D-313V-AL/B507V-Al if they are burnt?
PS:
By measuring: R77/R78: 47ohm,
R79/801,3K,
R81/82: 1,2K
all is as stated in the service manual
The power supply to the pre amp i get B +/_ appr. 58 V. is it normal or?
My knowledges in electronics is limited please help me for easy understanding why these transistors get burning if anyone can and what i must check etc.-
thank you!
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