Technics SA-103 TLC

swahl

New Member
I'm new here. I hope I'm in the right place. I've read a few posts that seem applicable in the first few pages, but I haven't exhaustively searched the forum first. Correct me in my ways if necessary!

I've got a Technics SA-103 from my high school days, and it needs a little TLC. The pots and input selector switch are noisy. The FM stereo decoder does not want to kick in unless I fiddle with the stereo/mono push button switch a lot. And, as long as I will have it open, the lights on the tuning dial indicator have gone out.

I'm no stranger to electronics, have taken plenty of things apart, rebuilt a tube based jukebox amp or two, etc. But this being my baby (more sentimental than real value I'm sure), I want to adopt best practices for this one.

For cleaning the pots and switches, I was hoping to find a generally recommended best practices sticky post or something. Both the input selector and the volume knob really need my attention here, the others are not nearly as bad. What products should I use for the Pots? For the selector? Caig has such a variety of products but they don't seem to be telling me exactly which ones I need for this. Deoxit (which one?) followed by Fader Lube? Or is Fader Lube only for slide pots? How about the selector switch?

For the FM stereo problem, do I just need to make an adjustment? Or, is it likely I need to replace aging electrolytic caps? The one thing I have going for me is over the years, this unit has been powered on at least once a week or so, it's never sat on the shelf unused for any length of time.

Finally, how to find replacement lamps for the tuning slider? Two bulbs, was it white and green?

Thanks for any help!
 
Welcome to Audiokarma! And also welcome to one of the greatest hobbies ever!

For cleaning, there is a Sticky in the General Audio part of this forum that has all you need to know: http://audiokarma.org/forums/index.php?threads/the-idiots-guide-to-using-deoxit-revisited.207005/

I'm not familiar with fixing FM tuners so will let someone else comment, but your best investment will be a service manual or schematics for this unit. There just happens to be such an animal for your receiver in the AK Database: http://akdatabase.com/AKview/displayimage.php?album=39&pos=4 That will give you info on where to start looking for the problem. If it's related to that Mono push button, it just may need cleaned up.

For lamps, check them with a multimeter to see if they are actually burned out, and then if they're not soldered to their wires try taking them out and seeing if there is a part number or voltage/current specs on them. Parts Express has a good assortment of old-school receiver bulbs.
 
Well, I got to this last night.

The most important thing was probably the DeOxit on the controls. Getting this apart far enough to get to the controls isn't easy, you have to get the radio dial all the way off the front of the unit to really get in there. I was successful, *but* on replacing the radio dial cord, I must have put too much tension on it because I broke off a little plastic nub that held the right hand side pulley block vertical (instead of two screws, it has a screw and a hole that the plastic nub fits into). I ended up drilling a hole for a second screw where the nub had been to repair this.

Aside from that, the DeOxit cleaning worked well. I shot DE5 in there where I could, ran things through their ranges, and then on the pots shot some FL5 in there. The result sounds just like new.

I was also able to fix the FM stereo with an adjustment to a trimmer as documented in the service manual. Thanks for the pointer to that!

I've given up on the dial lights, however. I had replaced them back in the 80's, and they burned out again soon after. The real problem, though, is the lights travel back and forth with the dial pointer. The wires have become very stiff over the years, and they are interfering with the dial pointer movement, so I've just removed them from the dial pointer and tied them back in a fixed position. With my experience breaking the pulley mounting, I don't want to fuss with the dial mechanism any more than necessary!

That's an aesthetic problem, anyway. The receiver is now working well, and that's the main point. I use it in my music making / office corner of the basement, with a mixer / computer audio interface in the tape monitor loop. So the receiver selects CD/phono/radio to go into the mixer, and the mixer output comes back to the receiver for amplification on the rare occasions when I use speakers instead of headphones. Having the volume control and source selector cleaned up is going to be wonderful! (I also have a SL-5 turntable, RS-M226 cassette deck, and SL-P120 CD player in this system, in case someone cares.)
 
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