Japanese Victor RC M70 repair

[aiwapanasonic]

I need to open my Victor on the weekend. There may be places like this with some glue; which shouldn't cause any issues normally. Some glue turns conductive on cassette decks but I haven't read about any issues with conductive glue on the M70.

This is the video I was referring to, over 2 hours long:

here's another video and you can see that resin is there on the Victor model at 9:36

 

[SpicyLuckster]

Based on this info, I think the yellow substance is actually a yellowed glue adhesive to keep them in place.

 

[SpicyLuckster]

So I tested it out today after deoxit-izing the controls with D5 and F5, and I switched it on, the speakers popped once but then went quiet. I powered it using the mentioned Toshiba laptop charger (I got a friend to swap the polarity on it for me), set it to line-in, and all I can hear is a faint static now coming from both speakers, it gets louder when I adjust the volume. I proceeded to connect my laptop to the bluetooth receiver and test some sounds, it's not much that comes out of the speakers, just minor pops. This is obviously better than the previous crackles and loud static, but now it's just quiet/no audible sounds accompanied by soft static. If it helps to include, the red power indication light isn't illuminating when the power switch is on, either. Any further guidance?

 

[Superduper]

The blob that you are seeing is setting wax, used to prevent movement of certain critical components and coils once the tuner (and that IS the tuner board) is properly aligned. You should not do anything to that board, don't even touch or handle it if possible. Those soft copper coils and even the position of some of the caps and transistors are critical. If you accidently move the components or distort the coils, you could cause the tuner alignment to drift. It is easy to accidentally touch and move or distort parts when handling that board.

If the power LED is not illuminating, then I suggest you clean the power switch which is a leaf type switch. Clean it carefully because they are easy to break and if you break it........... well let's just say you'll be wishing you didn't mess with it. If the switch is operating properly, then you should test the power LED to see if it is toast. You can generally do this with the diode function of your digital multimeter. If it illuminates while testing it with your meter, then the next area of concern is the voltage regulator that supplies power to it. There is a voltage regulator that powers not only the power LED but also the dial lamp and the MMS. If your tuner light will not light, the power indicator is out, and the MMS does not function, it's a good indicator that this regulator is out. This X505 regulator is hard to access and you might not be able to service it without taking the main board out, which is a big deal.

But since you are unable to address the power supply either, I'm afraid this service will definitely be beyond your comfort level.

 

[SpicyLuckster]

The blob that you are seeing is setting wax, used to prevent movement of certain critical components and coils once the tuner (and that IS the tuner board) is properly aligned. You should not do anything to that board, don't even touch or handle it if possible. Those soft copper coils and even the position of some of the caps and transistors are critical. If you accidently move the components or distort the coils, you could cause the tuner alignment to drift. It is easy to accidentally touch and move or distort parts when handling that board.

If the power LED is not illuminating, then I suggest you clean the power switch which is a leaf type switch. Clean it carefully because they are easy to break and if you break it........... well let's just say you'll be wishing you didn't mess with it. If the switch is operating properly, then you should test the power LED to see if it is toast. You can generally do this with the diode function of your digital multimeter. If it illuminates while testing it with your meter, then the next area of concern is the voltage regulator that supplies power to it. There is a voltage regulator that powers not only the power LED but also the dial lamp and the MMS. If your tuner light will not light, the power indicator is out, and the MMS does not function, it's a good indicator that this regulator is out. This X505 regulator is hard to access and you might not be able to service it without taking the main board out, which is a big deal.

But since you are unable to address the power supply either, I'm afraid this service will definitely be beyond your comfort level.

I'll clean the power switch the best I can, and see what I can do regarding the power indicator, will definitely be disassembling the boards this time to get a better look at them. I may not be the electronics wizard but anything's worth the shot. Thanks, Supe.

Regarding the static, I've looked around at other forums and often they mention the muting circuit, and your stated voltage regulators. Any other causes could lead to this?