KR-7600 rt ch pops in FM

KR4me2

New Member
Great site! Thank you "mods" for your time and efforts. :thmbsp:
Found a clean KR-7600 with no power. On/Off sw was pretty lose from front side. Found the contacts inside of switch toasted/gone and some of the bakelite broken! Was able to use the other side of the STDP contacts and we now have power after repalcing the 6A main fuse. (Am currently using a Poiwer strip to save my precious remainig contacts until i can add a relayed power sw circuit or see if the Pioneer SX sw i ordered will mount up)
Deoxed/cleaned and amps sound good. Problem is that when first tried the FM Stereo got a terreble pulsing from both channels when on dead center of tuning. Off center or mono the output would clean up but of course not in Stereo. Fired KR up the next day and wow FM seems to work but with the right channel poping at random when the tuning locks in the PLL section. Again off center and poping ceases. Traced the pop back to pin 5 of the HA-1156 MPX. Have IC on order now.
The queston i have is that the tuner board in the KR-7600 i have is marked p/n X05-1420-10. The SM calls out p/n X05-1320 and the schematics nor board layout are the same as the X05-1420 in the receiver? Anyone know where i can find the schems for the X05-1420-10 tuner board?
 
Thank you kindly sir. Yes those are the ones i too have from the KR7600/6600 SM from AK. In my searches i saw one reference to a KR-4010 manual that contained addendums of "various Tuner" boards but those did not include this particular X05-1420-10 board either.

Received a used Pioneer SX receiver ASK-507 Power switch (ALPS N-327) and the operating lever is the same type and length as the stock KR-7600 (ALPS J-271) with the bown contacts and broken bakelite. The mounting holes are different as is the housing but low and behold it fits into the stock slot almost perfectly. Just a little bit of filing the bottom of the chassis sheet metal and the switch sits perfect. Drilled two new mounting screw holes in the face of the hidden sheetmetal and a perfect fit. Moved the transient cap from the old switch and the stock Kenwood beuaty knob fits fine. I now have a solid "vintage" power switch back in the working Kenny. :music:

While waiting for the HA-1156 i noticed some green oxidation on the 4 gang variable Tunning cap where the spring metal contacts touch the center of the tuning shaft. This was after the intial compressed air blow out and Tuner Solvent cleaning. Hit those stuborn areas with Tuner Solvent/Contact Cleaner again and then a drop of penetrating oil on the shaft where it goes through the pot metal and on the contacts. Worked oil in good. Tunning cap was now way easier to turn by hand. Hit the nylon gear drive with a drop of Lithium Grease from the spray can as well.
Dried all out with compressed air then let it sit. Fired it up later. Well all be, the tunning circuit is now smother than ever and the right channel popping is missing? How the tuning cap can only affect one channel is beyond what i know as a shade tree bench tech. LOL But who am i to question the laws of physics! Anyone need a HA-1156 MPX DIP? No, ill hang on to it and tape it to the inside of the Kenny and maybe my son or his son will need it one day! LOL
 
Back
Top Bottom