Denon DP-30L Direct-Drive Turntable Service & Repair

I work on quite a few of these lovely Denon decks. Here’s a closer look at a Denon DP-30L I serviced recently, and a reminder of why it’s important to take your deck to the right person for work.

For more Denon DP-30L goodness, check out this service and review article. This particular unit came to me having just had an Ortofon 2M Red moving magnet cartridge fitted, plus a new lead-out cable. You’d think she be good to go right..?

Cartridge Alignment Blues

The 2M Red was installed at a well known local hi-fi store. I have to say, this was easily the most misaligned cartridge I’ve ever seen, the images below don’t really do justice to just how bad this was. It’s safe to say that whoever installed this had little idea about what they were doing.

You’ll note that the cartridge is heavily twisted in the headshell. Some deviation from zero is acceptable, but rarely is much needed, certainly never this much. The cartridge mounting distance was also incorrect. No big deal, these issues were easily fixed.

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The less said about this the better I think. Just remember, this cartridge was installed by someone working in a hi-fi store, who supposedly knew what they were doing.

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DP-30L, as I received it.

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Cable From Hell!

There were a couple of other problems with this lovely deck. Firstly, the owner’s friend had fitted this new lead-out cable for him. Very nice of him to do that, for sure, but he used a the wrong type of cable and one that was really too thick/stiff for the job.

This looks to be a car stereo cable, purchased from a local electronics supplier and not what we would normally use for a turntable. It’s so thick that he was forced to Dremel out the back of the cabinet for it to fit. The job was done quite neatly, but there was a problem with quality control – you’ll see what I mean in a moment.

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This cable is stiffer than the power cord!
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Hmm… I’m joking around here of course, but this cable is really stiff!

I know what you’re thinking – “Mike, you’re always pretty harsh on these issues you find…” etc. The thing is, if this was done properly, I’d be OK with it and there would be no problem. The basics are there for sure. The problem is that the owner experienced intermittent channel drop outs after the cable was replaced. Can you spot why, from the image below?

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This is what you might call an ‘installed short’.

Hopefully you can see it – a whisker of copper from the new cable is shorting out signal and ground in the left channel. This is why the deck never worked properly after the cable was installed. After proper trimming, cleaning and inspection, the joints look like this:

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There’s quite a difference and I’m hoping that readers can see that the attention to detail I go on about really matters. Here is a tangible example, in this case making the difference between a deck that works and one that doesn’t.

Arm Lifter Repair

The last issue was that the automatic arm lifter was not functioning to drop the needle at the start of a record, or to lift it at the end.

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Layout of the DP-30L, arm lifter motor and linkages to the left.

The arm-lifter linkages were jammed, I disconnected everything and, after lubrication and careful  examination, I was able to determine that the mechanism had been put back together incorrectly. Presumably this was done at some point in the past, by someone troubleshooting the arm-lifter mech. Once I resolved this, the arm lifter worked perfectly.

Motor Service

Finally, I serviced the motor and made some adjustments to the master speed controls on the main board, so that when you switch from speed to speed, no adjustment of the vernier speed control is needed.

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First, the motor has to be removed.
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Opening up the motor then gives access to the rotor and stator sections. The bearing should be cleaned and re-oiled.

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I usually use a solvent to remove any greasy build-up inside the bearing well.
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Same applies for the rotor or bearing shaft.
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This is typical of the dirt that comes out of a bearing assembly.
Speed Control Adjustment

Lastly, the deck went to the workshop for some electronic adjustments. The deck is supported, to allow access to the main-board underneath. This is an extra step that most would never do, but it makes the difference between a deck that works well and one that works perfectly.

What I did here was to restore the range of vernier speed control, so that it operates right in the middle of its range. An equal number of turns of the knob up and down produce the same speed adjustment up and down, say 3% each way. Additionally, both speeds (33 and 45 rpm) are spot on now when you switch between them, without needing to fine tune them with the vernier.

The deck now works perfectly, as it should after a service like this. To quote the owner: “Sounds friggin amazing, thanks Mike!”

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Beautiful! Job done, the owner is very happy. To quote the owner: “Sounds friggin amazing, thanks Mike!”

3 thoughts on “Denon DP-30L Direct-Drive Turntable Service & Repair”

  1. Great stuff but painful to see what is happening these days with TT. Most people have no idea what is important and how to fix it. Do you do also measurements for speed and Wow and Flutter, to check if the motor is running perfectly and the bearing is in good condition? Yes you need an analyzer and special Testrecords. Anyway, you are doing lovely things with care. I really like that. Regards from Holland.

    1. Hi Chet, yes agreed, I have a wow and flutter meter along with a huge range of other test and measurement equipment, test records and tools. I’ve been doing this a long time so wow and flutter analysis is only warranted when I test a deck and hear something not right. I listen to every deck I service of course.

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