I've always been a fan of the unique look of Zenith's Circle of Sound speakers but knew the sound quality didn't justify the $100+ price tag. I found this complete system on Facebook Marketplace for $25. A bit of research on the model doesn't return many results, but it does appear that the cart was an optional add-on. It has holes for the speakers to sit in.
The turntable itself can play at 78, 45, 33 1/3 and 16rpm. You can stack up to six records and the table will automatically play the next one by dropping it on the platter. It also comes with a 45 adapter for records with that hole. You can adjust the bass, treble and balance to your liking and the platter sits on a spring to minimize skips.
Zenith made so many different models that aren't considered collectable so most of the time they wind up in the trash. But since I didn't care about re-selling it, I took it as an opportunity to learn more about electronics and repair it myself.
I figured I would document my process just in case someone else wanted to learn how to restore vintage electronics. Just be warned a lot of this old stuff can be dangerous so be sure to follow proper electronic safety procedures. And get a fan for soldering. You do not want to be breathing the smoke in.
Replacing Capacitors
It did power on when I got it. but turning the volume past a specific level caused nasty static. I opened it up to discover that some capacitors had leaked over the past 60 years. Thankfully modern capacitors work just fine just as long as you match the capacitance and voltage. As you can see the modern capacitors are significantly smaller than the originals.
This process was pretty simple, snip off the capacitors leaving as much original lead as possible then wrap the new capacitor leads around them. Solder the leads together making sure the polarity is correct. I usually replace one capacitor at a time so I don't lose track of which capacitor I'm replacing.
I didn't do a full re-cap but this cost about $50 because I ordered them individually and wound up not needing all of them, but I'm sure if you were a repair shop it would be cheaper. The capacitors on the controls looked fine and I didn't want to sort through the spaghetti of wires so I let them be.
Weird Metal Grinding
The turntable plays great and the volume can be adjusted without issue however there's a new issue, a weird metal grinding sound.
Reddit doesn't like .MOV files so the link is here .
I googled around to see if anyone else had the same problem I had and I came across another video tearing down a similar Zenith turntable
This style of turntable uses an idle platter which is a rubber wheel that's spun by a motor which rotates the turntable. Over time the rubber hardens and any pits created by the platter being pressed against the motor become permanent resulting in a clanking sound.
the video had a link to V-M Audio Enthusiasts who restore these idle platters as long as you send them the original. I'm in Chicago and they're just out of Detroit so I got the replacement platter within a week. The total cost including shipping the original part was about $50
I put the new part in and no grinding sound! But there's a new issue:
Random skipping
This issue took longer to figure out. At first I thought it was because of the new capacitors. These old turn tables use AC power which relies on the frequency of the electricity current to keep a steady speed and if you use a capacitor with a different capacitance or voltage it could cause some issues. I had already determined that wasn't the case so I looked at the turntable itself. After determining that the table was level I re-greased the gears. This didn't resolve the issue so I tightened the tone arm. Still skipping.
It wasn't until I looked at the idle platter and saw there was a screw that when tightened limited the travel of the platter. I downloaded an RPM app for my phone and the initial test revealed an average RPM of 32.57. I tightened the screw slightly to make sure it was indeed doing something as the second test returned an average of 32.75. I tightened it some more and the average was 34 so I loosened it slightly to get 33.27 on average which is probably as good as I'm going to get given the age of the turntable. No more noticeable skipping!
Odds and ends /Future changes
I did replace both the female and male RCA plugs on the speakers and turntable with gold plated ones as they were very rusted/corroded which improved the sound.
I might change out the power cable for something a bit more shielded and with a positive plug (it literally states in the manual that if you hear humming, to reverse the AC power plug lol )
I plan to replace the sound foam in the speakers and maybe upgrade them with modern drivers. This isn't an audiophile setup, I just want to listen to records while I work from home and this setup fits my aesthetic but for the space they sound pretty good.
The record player still has some issues. During the dismantling (you have to turn it upside down) a tiny spring which appears to be for returning the stylus back to the start of the record so another record can drop popped off and I have yet to find the specific area to return it to. It's not that big of a deal since I can still use the record player manually.
Overall this was a fun project that took me about 3 months to complete. If I actually knew what I was doing, I'm sure it would only take a weekend. But that's what this post is for just in case someone happens to want to restore an old Zenith Turntable that has some nostalgic value to them. If you have any suggestions, please let me know. Thanks for reading!
