• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

JVC R-X60 Receiver - Equalizer works only on one side

ProBlogger

ProBlogger

Well-Known Member
I just finished cleaning out my first piece of good gear that I bought in 1983, a JVC R-X60. I cleaned out the inside, cleaned all the pots with a can of duster, and everything fires up and works great. However, as I listen to it through my headphones I can tell that the onboard SAE graphic equalizer is only working on the left side. Any thoughts on how to get the other side to kick in?

index.php
 

Attachments

  • IMG_0496.JPG
    IMG_0496.JPG
    80.5 KB · Views: 193
Register to hide this ad
ryuuoh said:
Has the unit been out of service for a while? Might still be dirty controls.
Click to expand...
Yes unit has been sitting for about 13 years. I've cleaned it very thoroughly, so next step is to recheck all the connections and spray it down one more time unless anyone else has some other suggestions.
 
I had this problem with an R-X40 that I bought. I ended up re-soldering everything on the SEA PCB. It works fine now. Look at it with a magnifying glass to see if there are any cold solder joints. I could not see any that looked bad, but re-soldering all fixed it.
 
From what I've read, don't use deoxit on the EQ sliders, I think you want fader lube for that.
Nice receiver. I bought my girl friend a R-X40 back then.

Hope you get it back to its former glory again!
 
Hey ProBlogger, I was just wondering if you made any progress on this. I picked up another R-X40 from a recycler for $17. It is actually not in bad shape. The cord was cut, so I bought a new one and installed it. Before I bought the cord, I tried to see if any of the output transistors were shorted. I couldn't get a good reading with my meter (it's hard to get the probes on the leads and harder to remove the bottom), so I said the hell with it and powered it up and watched for smoke. At first nothing lit up so I turned it back off. Then I realized none of the tuner buttons were pressed in. So, I pressed FM and powered it back up. The display lit up and it clicked a couple of seconds later . Yay! The bulb that illuminates the SEA logo and also lights up the text on the cover over FL display was out. I checked the DC offset and it looked OK (under 10mV both channels), so I plugged in my headphones. The controls were a little scratchy so I worked them back and forth about 50 times. It plays fine except the EQ acts very strange. Saturday, I replaced the bulb (12V 100mW, BTW) and replaced the power cord. I took the front off and put a small amount of Fader Lube in the EQ , VOLUME, and BALANCE controls. It helped the Volume and balance, but the EQ still has problems. If I start all five at 0 db, I can reduce the EQ and both channels work as expected. When I increase the EQ above 0 db, nothing happens. I am wondering if C559 / C561 or other cap is bad and not letting the signal through? I'll attach the EQ schematic. It is actually from a R-X80 because I'm too lazy to scan my R-X40 SM. I believe they are the same board though.

R-X80 SEA.PNG

It will be a while before I get back into it. I was just wondering if you made any progress.
 
Last edited:
No progress...other than the EQ works now. I guess it just needed a few hours of running after sitting for so long.
 
That makes me think even more that it is caps. I'm glad it is working now for you. I'll bet it sounds great.

There was a real nice R-X80 on the auction site recently. No one bid on it the first 2 times it was listed. It is in very clean shape. Last time it was listed, a couple of people bid. It went for $80 something dollars with about $40 shipping from Canada. I wanted it but figured my wife might kill me if I keep buying this stuff.

I had to rescue that R-X40 from the recycler. I could not let it go to the schredder! I might play it for a while this weekend. Maybe it will fix it too.
 
Pretty much.

Lots of electronics with lytics in it works better when warmed up. But ironically heat is what destroys them. Typical life.
 
Just to follow up on this. I played this receiver for a while. The EQ had the same symptoms as before, cut works, boost does not. After about an hour it stayed the same. I unplugged my headphones, raised the EQ sliders all the way up and turned the volume full blast with music playing through it. After a couple of minutes, I turned the volume down and centered the EQ settings. I plugged the headphones back in and the EQ works as it is supposed to. All bands work boost and cut. The Faderlube did it's job, all controls are quiet. I turned it off for a minute and the left channel did not have boost on the EQ. I unplugged the headphones and raised the volume EQ settings up again. It returned to normal operation. I might let it run some more. Maybe those caps are reforming. Maybe I'll just recap the EQ board.

Here's a picture of it... Sorry it's a little blurry.

20160207_004534-2.jpg
 
So, I replaced the 12 electrolytic caps and it still has the same symptoms. Cut works, but boost does not. Could the op-amp be bad?
 
I had this problem on an r-x80.. took out the eq board and carefully reflowed all the solder joints on the back. That fixed it. I think a lot of heat is generated around that eq board so using a 3 inch external laptop cooler fan to extract air from the cabinet might help. These do tend to run warm in use . Hope you manage to sort it.
 
Thanks for the reply. I think you are right that the EQ PCB gets a lot of heat because of a big transistor nearby.

I have two R-X40s. Both had these EQ problems. The first one I fixed by reflowing all of the solder joints. I was trying to actually troubleshoot the second one and make sense of what is happening. The way it was acting, it seemed like a bad cap or one that needed reformed. If that were it, replacing the electrolytics should have fixed it. On the first one, I was kind of thinking the heat from the soldering iron may have done something to "wake up" some component (electrolytic cap) because i did not see any obvious cold solder joints. I have used a plastic pick to tap on the PCB too. If it were a cold solder joint, that should have got something acting up. What really gets me is how you can turn all EQ bands up and raise the volume up high for a minute or so (no speakers or headphones connected) and after that all works fine until powered off. That's why I was almost sure it was a bad cap. I haven't had a chance to mess with number 2 lately. Maybe I''l just stop trying to figure out what is really wrong and resolder the whole board.
 
You must log in or register to reply here.
Back
Top Bottom