The solution to jogwheel problems with vinyl mode enabled

Engine DJ Hardware Standalone Controllers
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As I mentioned in other posts, I sent my Prime 2 to Algam, the repair center in France, regarding a playback issue on the right jog wheel when vinyl mode is activated.

This resulted in poor touch detection on the surface of the right jog wheel and/or, conversely, phantom touch detection, causing playback interruptions as if you were randomly touching the jog wheel when you weren’t.

This seems to be a recurring problem on some Denon DJ units. Browsing groups and forums, we can see that this particularly affects the Prime 2, but also some Prime 4 units, and to a lesser extent, some SC Live series units.

In most cases, you’ll simply see users mention grounding issues and simply advise disabling vinyl mode.

While this may be a workaround for many users, I think it’s a bit like having a warning light come on on your car dashboard, but simply removing the light bulb from that light. You no longer see the light, so you no longer see the problem, but the problem is still there.

So, I’ll try to separate fact from fiction and explain concretely what’s really going on.

The first thing you need to know if you’re experiencing this problem is that there’s no point in looking for software solutions, such as a factory reset or downgrading the firmware. This is an internal hardware issue within the unit.

What’s really going on?

It seems the culprit (or rather, culprits) is a series of faulty 2SK1828 MOSFETs causing internal ground issues.

This ground “interferes” with the touch calibration sequence of one of the jog wheels during the unit boot and can sometimes even cause problems with the buttons.

Since this “interference” is quite random, sometimes your unit will start without a problem, sometimes it will start with problems. And if you touch a metal part of the unit or the surface of the problematic jog wheel during the boot sequence, this “interference” is canceled by your body’s conductivity, and your unit won’t crash.

In the case of my Prime 2, four MOSFETS had to be replaced (Q3, Q4, Q5, and Q6). The service report also indicates that a jumper was replaced.

So yes, this problem is indeed due to a grounding issue, but it’s an internal grounding issue within the device, not an external grounding issue (power strip, power cable, or related to the location you are in).

Hope this article will be useful to some people :slight_smile:

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Nice to know about this. Where do these MOSFETs are located in the device? On what board, how far away from the PSU?

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And remember folks, what’s been damaged in one prime unit doesn’t necessarily mean is faulty in every Prime model.

One repair shop, repairing one prime unit won’t be able to make sweeping statements which “fix” any other prime … even if they claim to have had “a couple like that”

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I don’t have the exact locations; I only have the identification of the faulty MOSFETs and some explanations that the technician was kind enough to share. So, since I don’t have access to the service manuals, I unfortunately can’t answer this question.

But I’m sure there must be some electronics experts here who have already disassembled their Prime and who can provide more details and maybe even take some photos.

Of course, I’m not saying it’s always these four MOSFETs; it could very well be just one, two, or three of them; it could even be similar MOSFETs located in other locations for the left deck. But it seems this is a common defect in a whole batch of 2SK1828 MOSFETs used in some Denon DJ products.

So I’d say these MOSFETS should be the first avenue to explore and the first components to check for anyone with soldering skills who wants to repair their unit themselves.

Of course, I always encourage you to go through an authorized service center if your unit is under warranty, or a professional technician if you don’t know what you’re doing. It seems that just disassembling and reassembling Prime units is a nightmare in itself.

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Again , just because one of the mosfets were defective in one particular Prime 2, doesn’t mean “OH my god every mosfet xyz in the same batch is defective around the cosmos” -

There used to be a repair guy on this forum who used to Cry Wolf a lot but thankfully doesn’t post much since learning his lesson

So, yes, there might be a prime 2 with one or more poorly mosfets in it, but few service centres have seen a dozen prime 2 , less still will have seen 25 prime 2s… so it’s not possible to really justify any inferred bias of “one prime 2 had a mosfet issue, so 50 or 100 or 1000 of them must have a mosfet issue, in any viable way, aside from perhaps unintentional scaremongering

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Enfin une solution! Merci pour ces informations précieuses!! :innocent:

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Thanks for reporting your issue.

I think I might have this issue on my prime 2 also. My right deck sometimes stutters playing music. Also when I use my right jogwheel to fast forward to parts in a track it doesn’t sound like it should.

I downgraded to 4.0.0 the other day thinking it might be a software issue but it still happens. I will try turning off vinyl mode later on.

I have already had repairs on the same right deck from Technosound about 2 years ago.

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Thanks for specifying what you’ve found out about this issue and compiling all information into this post! Good to know what specific part of the device was causing it, and will be helpful to point out to technicians to look at that first. Also, in my DJ lifetime I’ve encountered such issues only on Prime 2, I mean, on every Prime 2 (out of 2 of them which I’ve seen / touched), and didn’t see such issues on Prime 4 / 4+ / GO, at the same time I can’t be sure if I heard about this issue rarely happening on SC Live 4, but there might have been one instance

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I’ve seen a few posts on a few Facebook groups from people having issues with touch detection and/or intermittent audio cutouts due to phantom touches on one of the two decks on some original Prime 4s, always when vinyl mode was enabled.

The Prime 4+ seems to be significantly less affected. However, the Prime 2 does seem to be particularly affected.

The most logical explanation would be that there was a batch of defective MOSFETS in a number of units produced between 2019 and 2023, and that starting in 2023, these MOSFETS were replaced by a new, much more reliable batch in the production line.

The problem is that most of the affected units won’t necessarily have been sent in for repair during the warranty period, as most users who only do beatmatching without scratching will have simply disabled vinyl mode to avoid the problem. Which was less of a hassle than being without the unit for several weeks.

Which is a shame because many original Prime 2 and 4 units currently on the used market can be affected by this hardware issue, never repaired under warranty, and therefore lose a lot of resale value.

So I think one of the first things to check when buying a used original Prime 2 or 4 is to enable vinyl mode on both decks and play tracks to see if the jog wheel’s touch response works as expected and if no intermittent audio dropouts occur.

And to perform this test over several successive reboots to ensure that it’s a fully functional unit as it should be.

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So after playing around all weekend with my prime 2 on different occasions. I have turned vinyl mode off and not had one single problem with crashes or music stuttering.

How much did it cost for all your repairs and parts?

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The total cost of the repairs was €110 (parts + labor + shipping/returns) at Algam, the official Denon DJ repair center in France.

This price includes shipping the unit to the service center (€25) and returning it to my home (€25).

So the repair itself represents around €60 of the total bill, knowing that the components don’t actually cost much. It’s the labor and time spent disassembling and reassembling the unit that cost the most.

I think it was worth it to have a unit that works perfectly as it should and is completely bug-free now.

As I mentioned in one of my previous posts, there’s a trick to bypass this internal ground issue and keep vinyl mode active without the sound stuttering or jog wheel touch issues.

Usually, the problem only occurs on one side, either the right or left deck. For some reason, the right deck seems to be the one most affected in most cases.

The trick is as follows:

  • Immediately after turning on the unit, place one hand on the jog wheel surface on the side where the problem occurs, and with your other hand, touch another metal part of the unit, such as the mixer faceplate or the opposite deck, during the entire startup sequence (until all the LEDs stop flashing).

Your natural body conductivity will act as a jumper between the defective deck and the rest of the unit, thus canceling out this interference that distorts the tactile calibration sequence of the jog wheels that occurs when the unit starts up.

Once the unit is started, you should be able to use the unit normally with vinyl mode active on each deck without encountering any problems.

While this tip may be a workaround that can help, I don’t recommend it for long-term use.

Firstly, because you’ll have to repeat it every time you start the unit, and secondly, because this isn’t intended to be a normal use of the product. Furthermore, you’ll be left with a defective unit that will therefore lose a lot of resale value if you come across someone who wants to scratch a little or even do some backspin during its performances.

Given the moderate cost of the repair, I think it’s better to have the unit repaired.

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