Question about vintage receiver

famous beagle

famous beagle

Well-known member
I bought a vintage Kenwood receiver and turntable at a garage sale a while ago. Until recently, it's always been finicky when playing records. It has two phono inputs, but regardless of which one I plugged into, one side would kind of crap out, and I'd have to tap the top of the receiver to get it to come back on.

This morning, I wanted to test out the AUX input to see if I could run my new Sony TC-530 reel to reel into it, so I just played some music on my phone through it to test it. It worked great. So I decided to put it through the phono inputs just to see what happened.

I know phono is not a line-level device, so I turned the volume all the way down at first. I slowly rolled up the volume and, though the sound was distorted (because of the level mismatch I presume), there was no shorting/crapping going on at all. Both sets of phono inputs seemed to be working fine.

Just for shits, I plugged my turntable back into phono 1, and ... now it seems to be working great, with no crapping out. ????

WTF?

So my question is, could what I did (run a line device through the phono jack) have somehow cleansed an issue or something? Why did it all of the sudden start working? I've played dozens of records before now, always with the same crapping-out-on-one-side result. Now all of the sudden, it's working great. I even tapped the receiver to see if it would trigger a crap-out, and it still worked fine.

Any clue?

Thanks
 
I would clean everything up real well. Not just the jacks but the switches as well with deoxit.
i have an old kenwood kr 9400, a big boy with 120 watts a side.
love it. Sounds stellar. Ive had it since new when i got it in 79.
Almost all the lights are burned out, but it still performs flawlessly. Every couple of years, I open it up, blow the dust out and clean it all up.
Just keeps working and sounding great.
:-)
 
I used to have that issue on a mixing console. Cranking the signal sometimes fixed the drop out. Eventually I discovered that working the switches was a better treatment so I'm guessing there's some buildup on the contacts in the switch that puts something (capacitance?) in the path.
 
The phono inputs could be dirty and oxidized. Plugging in and out of them a few times could of cleared them a bit and gave you better contact. It's always good to douse a pipe cleaner with deoxit and run it through those old RCA jacks.
 
Yeah. Too many people just spray inside and clean the ground sleeve. You get a good looking shiny rca jack that is still dirty.
pipe cleaner is the best
 
I'll have to try the pipe cleaner idea. I haven't done that.

I did open the thing up a while ago and did blow it all out with compressed air. I can't remember if I used deoxit on the switches or not while I had it open.

Actually, come to think of it, I did just spray some deoxit on the source switch yesterday just from the outside (took the knob off and did what I could externally, spraying at the base of the shaft and turning the pot back and forth). I don't know why I didn't think of it, but that must have done the job. I had planned on taking it apart and deoxing from the inside (and I'm sure that wouldn't hurt), but something came up, and I had to leave before I could take it apart. So I just did the quick external job before I left and forgot about it.

But I guess that did it. Awesome!

Yeah I love that old thing. And now I'll probably use it much more considering the fact that it's working. One of the first albums I bought on vinyl when I got the system was Roberta Flack's debut album from 1969, First Take. Holy crap .. that album just sounds soooo good. I mean ... I know people talk about how clear and clean recordings sound nowadays, and you can hear each instrument, blah blah blah, but ... I don't care how they did it: that album sounds amazing. Warm and pleasant are the first words that come to mind.

The first track, her cover of "Compared to What," is just as warm and funky as it gets. And of course it contains "The First Time Ever I Saw Your Face," which is a masterpiece.

RFR: I'll have to check the model number of my Kenwood. I don't even know what it is.
 
The Ghost of FM said:
Before the days of deox-it, folks used to burnish their connectors with a gritty surfaced insertion tool to clean off the oxide.



Cheers! :)
Click to expand...

Yes I've seen Gerald Weber do that on some old Fender amps in one of his amp instructional videos. I don't have a burnishing tool, though.
 
+1. Cleaning switches is always good practice.

I'm reminded of the common issues with LCD screens and their PSU caps, although I don't know how relevant it is.
Still, it'd be interesting to see if your phono inputs cease to work again after a day or so of not being used.
 
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