Is this turntable worth fixing?

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madhatton
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Is this turntable worth fixing?

Post by madhatton » 02 Nov 2019 18:33

Hello!

I'm new here, both to this website and to the vinyl scene in general. A few days ago, I was talking with a co-worker about music and mentioned that I wanted to get into vinyl. Well, it turns out that this co-worker is a bit of an audiophile, and said he had several turntables lying around that he didn't use if I would like to look at them.

The other day, he brought them in and straight-up gave me four turntables. Two are vintage novelties that work, but I'm not planning on using them that much (I've developed a bit of a reputation as a collector of old tech due to my job).

The two nicer tables are a Pioneer P-112D and a JVC QL-F4. The Pioneer had no belt, so I ordered one, and hopefully, that will be that. However, the JVC is not working. When the start switch is flipped, or the tonearm is moved to the platter, the platter moves extremely briefly- I'd say for maybe a quarter of a second. It's more of a twitch, really. I downloaded the service manual for it, but I have limited experience repairing electronics with circuit boards.

Is it worth fixing the JVC? There's a part of me that would certainly like to- I've read good things about it. But if it would be too difficult for me to perform the repair myself or prohibitively expensive to have it serviced, I will regrettably not bother.

paddypaws
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Re: Is this turntable worth fixing?

Post by paddypaws » 02 Nov 2019 19:49

It certainly is worth fixing, excellent quality and specs similar to a Technics sl-1600 mk2. Does it detect that there is or isn’t a record on the platter like a sl-1600, which will only start briefly if there’s no record on the platter.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 02 Nov 2019 20:21

If it does, then it's constantly detecting that there is no record on the platter. It behaves the same whether or not there is a record on it. However, there is one new development. The turntable twitches upon plugging it in.

Also, the strobe lights that indicate consistent rpm speed don't light up. They did initially.

AsOriginallyRecorded
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Re: Is this turntable worth fixing?

Post by AsOriginallyRecorded » 02 Nov 2019 21:21

As a simple, can't do any harm exercise, try plugging the TT in and leaving it "on" for a day or two. There have been others who have done the same with various brands of TT that have been out of use for some time and have had positive results. It appears in these cases, that the capacitors have lost their charge holding capacity over time, and were actually able to regain capacity after receiving such a "boost". Worth a try. Sorry I can provide some more details and specifics, but the twitch description triggered the memory for me. Definitely a worthwhile TT to get up and running if not too complicated or costly. [-o< :)

spensar
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Re: Is this turntable worth fixing?

Post by spensar » 02 Nov 2019 21:43

For the JVC, a simple first step is to remove the bottom and check for micro switches and spray some contact cleaner in there. You can get some pretty inexpensive ones vs. going the Deoxit route.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 04 Nov 2019 05:07

Alrighty. I'm going to try to get it up and running. I was finally able to plug the Pioneer into some speakers and, well, something isn't happy. I may need to replace the RCA cable. I put an old Christmas record with no value on the platter just to see if everything was working (even though it has no belt, I figured I could turn the platter manually to make sure sound came from the cartridge and everything) and upon plugging in the RCA cables, I got very little sound but lots of very loud pops and hisses. So I'm not sure what to do about that. I also plugged in the JVC, and there was thankfully no noise of that nature.

vanakaru
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Re: Is this turntable worth fixing?

Post by vanakaru » 04 Nov 2019 09:12

Pops and hisses indicate that there is some continuity problems on the line from cartridge coils to RCA plugs. First spot to check is cartridge wires, then RCA plug(unless you will not be able to open these), then where wires from the arm meet out cable. If visually everything checks out use multimeter to investigate further.
BTW you use phono preamp, don't you.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 05 Nov 2019 04:03

Alrighty. I'll check it out and yes, I have a preamp.

Back to the original turntable I was having issues with, I followed the troubleshooting flowchart for the JVC. My problem is "Transistors x805-x812 defective. motor lead from circuit board disconnected. Check for loose socket, floating pattern, and defective soldering." So I'm not sure which one it is. If I'm honest, I don't even know what floating pattern means. I'll attach a photograph of the circuit board. The two large capacitors have leaked pretty badly. I'm wondering if that's not my issue. Thoughts?

EDIT:

After further testing according to the troubleshooting flowchart, I'm not getting a consistent result. There is a resistor labeled R822 that must be short circuited, which can fork the path one of two ways depending on if the platter turns or not when this is done. Sometimes, the platter will turn. Sometimes it won't. When R822 does turn, one of the integrated circuit boards will also cause the platter to turn when certain pins are shorted. But when R822 doesn't cause the platter to turn, it doesn't. So I'm still not sure what to do.

EDIT 2:

Photos

https://drive.google.com/open?id=1CbEm2 ... lQ50LF1NFS

vanakaru
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Re: Is this turntable worth fixing?

Post by vanakaru » 05 Nov 2019 07:14

Looking at the pictures the first thing I would do is to replace the capacitors. Or at least unsolder these and check what this black substance is. It may be just a glue they use to attach the caps before soldering. If it is leakage you may have corroded connections where it has seeped on. Usually the old dying caps are cause of erratic problems. And I would clean it off in any case. That diode sitting in the pool of black goo may not act as a diode any longer.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 08 Nov 2019 05:33

I got the capacitors today, and I'll replace them soon. We'll see what happens [-o<

I also got a new cartridge and put it on the pioneer. No more crazy pops, but now there is no sound coming from the right channel at all (I made sure it wasn't the cartridge by putting it on the JVC and manually spinning the platter- bingo, sound from both speakers). I'm not sure how to test if it is the cable or the small wires coming from the tonearm. And if it is the tonearm wires, I haven't been able to figure out how to get at them to replace them.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 08 Nov 2019 06:47

I should also clarify: I stuck the entire cartridge/headshell to the JVC and I got sound from both speakers, so it's not the cartridge wiring.

Alec124c41
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Re: Is this turntable worth fixing?

Post by Alec124c41 » 08 Nov 2019 13:06

If you don't have one, get a digital multi-meter. Even a $20 one will allow you to trace the different sections of wiring to check continuity. The better ones will check capacitance, too.
If you got this far, I suspect you already have one.

Cheers,
Alec

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 09 Nov 2019 04:36

Well, there is some slightly good news. I whipped out the ol' multi-meter and confirmed that it is, in fact, the RCA cable.
Considering that the guy who gave these turntables to me just had them lying around, I'm not all that surprised honestly.
I'm not sure how they were stored.

I have continuity in the right channel from the tonearm to the RCA terminal (hallelujah! that would have made this a much harder job), but not from the terminal to the actual RCA plug, so there's my problem. I'll just need to solder in a new one. I ordered an RCA cable with a dedicated ground fork like the original, but it's a male-male cable. I think I can just cut it in half and I'll have a spare if it ever goes out again. So that's the Pioneer (hopefully) fixed and up and running. Next is the JVC... updates to come.

madhatton
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Re: Is this turntable worth fixing?

Post by madhatton » 10 Nov 2019 02:32

I am now able to declare victory over the Pioneer. I replaced the RCA cable, and while I cut it a little short (oops), it's far from unusable and I have sound coming from both channels!

On the JVC front, I was following the toubleshooting table again, dropped one of my test leads, shorted something out, and blew a fuse. C'est la vie. I've ordered new fuses.

spensar
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Re: Is this turntable worth fixing?

Post by spensar » 13 Nov 2019 14:31

Congrats, great feeling to bring a piece of gear back to life.

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