Help fixing Problem with Kenwood KRF-X7775D


Joined Feb 27, 2018
I have an identical problem in this model, what I have noticed is that the mute pin in test mode is 3.3v and in normal mode it is only aprox 1.2v on DSP board
So I fixed one couple of years back.

I remember no Audio output from tht either.

I did replace some DSP related SMD chips but to no Vail.

It was some capacitor issue. I recall couple of smaller caps and a super cap near a μC.

The PCB is at the bottom most. Where I'll know when I see the PCB.

Post some pictures of the inside so I can recall my rusty memories.

I think it was a uC not resetting issue. Well, tht's what I figured cause it still works like a charm
So now i am bag to the Unit... I have changed the Gold Cap... (only bevore disassembled the Unit) ..

The Unit can now only be switched in The Test mode by Pressing Input select and Power this was before easier to go into that Mode ;-)..

But the hole Sound in normal Mode is gone as well like before.

Now i disassembled the Unit and take out the Card´s and looked under the Layer Board for Inspection.

I found that the Big AC/DC Bridge is soldered out at all Pin´s could that be a Part of the Problem.. The Solder Pin´s are very cold and scratched.

I want to ask you if it is a good Idea to take out all Cap´s for testing it´s ESR and put in new ones with better ESR ( by the Same Cap and Voltage)

How about the AD/DA Board on the Photo with Software on a Flash is there a Way to look on it and if necessary change the Software on the Flash..

Thank´s for Today i come bag Tomorrow and we look forward to fix this Unit.. Jürgen
I have a same model and same problem . .we change the ADSP IC (ANALOG DEVICES). and its work again.same like brand new.