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