WJMX-50 Desynced input

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Hi everyone, first-time user here.

A couple of months ago I bought a Panasonic WJ-MX50, and I haven’t been able to get it working properly yet. I’ll explain what I’ve tested so far.

The mixing functions themselves seem to work fine — transitions, effects, etc. However, the input signals look dirty, desynced, and sometimes show tearing.

At first, I thought it might be a PAL vs NTSC issue. A friend suggested that could also be caused by a weak signal.

I checked the unit and noticed it was made in Japan (model WJ-MX50A, I think), so I assumed it was NTSC. Based on that, I bought some cheap PAL/NTSC converters from AliExpress.

This week I finally tested everything:

  • Camcorder → Source 1

  • HDMI (converted to PAL) → Source 2

  • Output → LCD TV

The converters didn’t really help. Also, my LCD TV seems to support both PAL and NTSC, so that probably isn’t the issue.

After more testing, I started suspecting the mixer might actually be PAL. I connected it to a CRT TV and confirmed that — the internal demo runs perfectly there.

I also read a similar post ( Panasonic MX50A Troubleshooting ) where someone mentioned that this kind of issue could be caused by ribbon cables needing reseating. I checked the cables, but I’m not sure which one handles the input signal, and everything looked fine to me.

I even tried an internal feedback loop (Output 1 → Source 2 via BNC), but no luck.

I’ve attached a video showing the demo running on my LCD TV and a video showing how the tearing / desyncing looks.

Furthermore, I’m not at all afraid of diving deep into the rabbit hole. Already got the service manual downloaded.

Any ideas on what might be causing the issue?

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unclear on what the specific issue is here

IF this is a PAL mixer then

  1. any NTSC source you put in is gonna be wonked up, if it shows up at all.
  2. any attempt to view output on an NTSC only CRT is gonna be wonked up, if it shows up at all
  3. using a cheapo hdmi to PAL convertor isn’t really going to give you reliable enough information to figure anything out b/c theres a very high chance that the PAL signal being output isn’t quite to spec

first thing to really drill down on is if its a PAL mixer and is otherwise working in perfect condition, because that would explain a lot. there is probably some way to determine this from serial numbering schema, this would likely require a bit of research

the other thing is that if you know anyone with a PVM/BVM crt monitor, they will typically be equipped to handle both NTSC and PAL signals, and will often display a readout saying NTSC or PAL when a signal is plugged in.

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possibly also: there might be a setting in the menu of your LCDtv that says what the active video signal is?

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Hi Andrei, thanks for replying. I’m almost for certain the mixer is PAL. I bought it from a audiovisual warehouse situated here in portugal, also on the back it says the input power must be 50 Hz which further points to PAL. My camcorder is PAL. As for my CRT TV it can take both signals but its PAL dominately because when i send a NTSC signal through it (i have a cheapo converter) the image goes to BW. So far I’ve tried PS2 video signal as well as the camcorder, what I’m thinking is either the digital frame synch went to shit or the signal im providing to the mixer isnt quite to spec as whats mentioned in the manual 10 Vp-p/75 Ohms (I think it’s the former because two input signals not working with the mixer, when they work standalone, is a bit suspicious).

As for the last part I don’t know anyone near me that has those PVM/BVM crt monitors or does anything a/v related for that matter, but ill keep it in mind.

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…they pop up on eBay (many offers from the UK = customs!) quite regularly, in Germany you can find them on kleinanzeigen.de - there are similar portals (that i know of) in the Netherlands, and Poland and in Switzerland (customs!) and if they ship and you pay for the shipping there shouldnt be much of a difference between shipping within Germany or to Portugal…

…i bought one a few years ago from Poland and it arrived in best condition…

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gotcha, yes if the power is 50hz then the hardware is PAL no doubt
if you opened things up and nothing looks obviously wrong, usually the next stage is testing and replacing capacitors (recapping), which i think has been mentioned in more than a couple other panasonic repair threads here?

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yeah. Trimpots too. The trimpots can really affect these. There are a ton of them on the AD board. Alcohol, then tiny amount of faderlube. Move them around. Caps can be an issue for sure, but they are not always. I had an MX12 doing very similar, but caps were not a problem actually it was more the trimpots which took a while to settle down.
I think if it’s not been used for a while the caps can reform when they get some electron flow again (run it for a while)
PSU caps can be a bigger problem though, and there are quite some small fuses in the PSU for different rails.