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Denon DP-52F won't spin. Repeated clicking

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Denon DP-52F won't spin. Repeated clicking

Postby grindfix » 15 Oct 2017 01:58

This was my main turntable until it decided not to spin one day. Did not have any issues playing it day before.
Platter tries to spin and makes repeating clicking sound resembling relay clicks. No issues with tonearm operation. I took bottom cover off and removed motor driver PCB to see if I can spot bad connection or bad solder joint but did not find anything and put everything back together and it came on! I have been running it for extended periods of time with tonearm lifted just to put load on the motor circuit to see if it fails to start after cool-off again. So far it hesitated to take off once and produced same clicking but within few seconds everything was normal again. I wonder if anyone experienced similar situation with Denon turntables. I assume most of Denon Quartz Lock drives are similar.
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Re: Denon DP-52F won't spin. Repeated clicking

Postby EdAInWestOC » 16 Oct 2017 06:17

You may have seen posts in this section of the forum from me before. I will say the same thing I have said before. The electronics of the Denon turntable has many electrolytic capacitors. Electrolytic caps have a finite lifespan.

Now that they are 20+ years old, the caps are all out of spec and the performance of your turntable is going to be unpredictable. If certain caps short out you are going to burn out hard to find semiconductors and your turntable will be a door stop...at best.

I suggest you recap your turntable or plan on buying another. No matter how many stories you can write about "now it works", there is nothing you can do to make your turntable reliable other than recapping the electronics.

The symptoms you will see will be associated with everything that the turntable does. If your turntable works but while listening you notice that notes are wavering, the caps are the culprit. If your turntable refuses to respond to its switches or pushbuttons, the caps are likely the cause.

No matter what anyone tells you, the caps are old and out of spec, or shorted. Don't bother looking for swollen caps. That is a symptom that sometimes happens to caps in the power supply of some gear.

All of the electrolytic caps need to be replaced. All of them. You might get by by leaving some of them in the circuit but they will fail in a short amount of time and you will be opening the turntable up again. If you want a reliable turntable you have to replace all of the electrolytic caps.

And again, I mean all of them. Nothing changes the fact that the age of those caps makes them unreliable. Electrolytic caps are mostly cheap and easy to replace. I don't understand people who waste their time by not replacing a $0.25 cap. Are they really saving money?

Of course not. The parts cost is so low that the consideration is the cost of the labor. If you hire someone to do the recapping job it is smarter to have them replace all of the caps while they are working on your turntable. Then the job is done...period.

If you are handy with a soldering iron then your time is wasted by not doing the complete recapping job. I have a DP-62L that was bought new in 1983. It was well treated and in spite of good care, it started to give me speed control issues. The "Lock" indicator flickered on and off.

The only way I could restore my 62L was to completely recap the electronics. The total cost for all of the electrolytic caps was under $40 USD (IIRC). Now that the turntable is recapped, it is reliable again.

One other warning...the main bearing in your turntable is not something that lasts forever. Denon may have referred to the main bearing as a life long bearing but that is an interesting term. The life long bearing is the life of the turntable.

Once the capacitors start to fail the turntable's life span is over. The life long bearing is also over the hill. Minimally you need to open up the turntable's drive motor and clean and relube the main bearing. Once you have the motor open visually inspect the thrust pad and if there is any sign of wear, the thrust pad needs replacement.

All of this is unwelcomed news. Denon made great turntables but the design of those turntables makes them unreliable when they get old. Many other vintage turntables work fine once they get old. Those turntables are much simpler devices with less to go wrong. Denon turntables do not belong to that group.

Sorry for the bad news but it is the truth.
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Re: Denon DP-52F won't spin. Repeated clicking

Postby Freddymac1 » 16 Oct 2017 14:19

I am in total agreement on the re-cap, but I have been told that the boards are very tender and can be damaged in the process. I would love to think it will only cost $40 but shipping can be $15, and I don't think I can get 40 good quality Nichicons at today's prices. Which grade is recommended?
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Re: Denon DP-52F won't spin. Repeated clicking

Postby captmark » 16 Oct 2017 23:22

The boards are not particularly tender, but you should know what you are doing as far as working a soldering iron to keep from burning/tearing traces or making a cold solder joint. Most 51/52f boards are not marked on both sides, so you need to be patient and double check you are heating up the right parts. Do NOT remove the boards to recap it...a guy sent me pictures once of his Denon board where he had cut and marked all the wires to solder them back together... Cutting wire ties, pulling a couple of ground wires and plugs, and depending on model removing (but not unhooking) the transformer from its mount will gain you enough slack to flip the boards where you can get to what you need. Using a bright light (with a magnifying lens doesn't hurt either) to shine through the board helps tremendously.

As a tip you should change the CDS photo sensors (under $1 each x 3 here), but even to this day after almost 200 Denons (!)I always do them last (if the arm worked going in) to see if my operation was successful. Then I change them. If the arm doesn't work going in I change the sensors first, then test it before going forward with the recap. More than one thing can cause arm issues, and chasing down two problems when you can easily rule one out equals a lot of wasted and potentially frustrating time.

I know this argument has been bantered around, but if the $15-$20 total dollar difference between jobber quality and audio grade Nichicon FG's (or similar Elna's, Panasonics, etc) is a determining factor in this DIY project for you I feel that much more blessed. I use the FG's if for no other reason their black/gold color makes it very easy to prove you've done a recap and know where you left off. It's true no audio goes through these paths, but in the overall scheme of things the probable tighter tolerances would eliminate them as a likely problem source if after doing the recap you have the same (or new) issue.
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Re: Denon DP-52F won't spin. Repeated clicking

Postby grindfix » 17 Oct 2017 04:19

Second one I have is DP-45F that has tonearm skate syndrome. I will start with DP-52F as it is in better shape.
Is there a BOM list posted somewhere?
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Re: Denon DP-52F won't spin. Repeated clicking

Postby EdAInWestOC » 17 Oct 2017 18:37

Freddymac1 wrote:I am in total agreement on the re-cap, but I have been told that the boards are very tender and can be damaged in the process. I would love to think it will only cost $40 but shipping can be $15, and I don't think I can get 40 good quality Nichicons at today's prices. Which grade is recommended?

Most of the caps are not critical. Its just general purpose caps with the exception of the two coupling caps that are between the servo pickup head and the speed control microprocessor.

I ended up using Nichicon FGs for those two caps because that's what I had on hand. Any audio grade coupling caps should suffice. Please remember that I am talking about recapping a DP-62L but your table should be similar.

The people who posted about the circuit board being somewhat sensitive are correct. Heat the solder until it flows and immediately remove the iron. The traces tend to crack and cause all sorts of interesting issues if you overheat the solder joints.
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