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Problem with MCP 737NG V3H

Posted by baw19 
Problem with MCP 737NG V3H
July 12, 2018 10:01PM
Hi all,

I've had an MCP 737NG V3H for about two years and it's worked perfectly all that time. However I upgraded P3D to v4.3 about a week ago and since then (coincidentally or not) the MCP LEDs go black and the unit hangs after random periods (sometimes a few seconds, sometime half an hour or more). The only way I can make it work again is to turn it off then on again and restart SIOC.

If I leave it hanging the LEDs flash every now and again but they remain blank and the unit still doesn't respond.

Similarly if I use the SIOC monitor, when it first starts I can see all the rotaries and switches doing stuff in the monitor window but after the LEDs go blank none of them work anymore.

Has anyone else suffered from this problem? Does anyone know how it can be fixed?

For info I'm running P3d v4.3 on Windows 7 64 bit with no other software other than the latest version of SIOC (v6). I've tested the power supply with a volt meter and it's pushing out 6.2v when it's not plugged into the MCP and I've moved the USB cable to a socket on the PC chassis to eliminate USB hub power problems. My chassis USB is v2.0.

I'm stumped. It looks more and more like a hardware failure but if anyone has any ideas to try I'd be really grateful - these units are so expensive, I simply can't afford to buy a replacement - I'm saving up for a pair of OpenCockpit FMCs!!

If it needs to be returned for a repair can someone tell me how to do so? It was purchased from Aviation Megastore 4th Aug 2016.

Video of the problem

Many thanks,



ps Forgot to say, I've checked that the sim power is on - it's not simply going black with a flat battery!

Edited 2 time(s). Last edit at 07/13/2018 08:39AM by baw19.
Re: Problem with MCP 737NG V3H
July 13, 2018 01:14PM
Have you updated FSUIPC to the latest version? P3DV4 requires FSUIPC5 to work.


Hope this helps


Re: Problem with MCP 737NG V3H
July 13, 2018 01:27PM
Hi Dave,

Thanks for replying! I updated a couple of days ago so I don't think it can be that.

Does anyone know if SIOC writes logs that I can look at?


Re: Problem with MCP 737NG V3H
July 21, 2018 03:12PM
For anyone watching this topic, or anyone who faces this in the future, I think it's a problem with the MCP itself.

I tried running the unit via a long USB extension to another PC running FSX and it still failed.
I bought a regulated 6v 2A power supply and used that instead - failed
I tried running it on a different household mains circuit (all protected by RCD) - still failed
I tried it through a different mutli-gang plug board - failed
I tried it on it's own power socket failed

The common factor is that when I turn on something else in the house (another PC, my jet washer, the sim projectors) it blanks out all the LEDs - thought it must be said that it's pretty random in which items will upset it and when. The backlights and switch lights stay on but the LEDs flash & go out and I need to power it down then up again and restart SIOC to make it work.

I think it needs to go back to Opencockpits for repair. Can't say I'm very happy, this is bound to cost me and expensive kit like this should not start failing after less than two years use.

Re: Problem with MCP 737NG V3H
July 22, 2018 11:54AM
To me this looks like a "loose" cable issue. I would have unscrewed the chassie and inspect and make sure all cable connections are connected firmly to t the sockets.
Re: Problem with MCP 737NG V3H
July 22, 2018 09:34PM
Hi Roarkr, something's not right but the only cables I know of are the USB and Power connectors and since the LEDs and the backlights all work reliably I think a capacitor may be on the way out. That might make them less able to cope with fluctuations in the power. I'll take it out tomorrow night and return it for repair - it'll be a good chance to peek inside and see if anything's looking loose before I send if off. Thanks for the idea!


Re: Problem with MCP 737NG V3H
November 12, 2018 01:36PM
For anyone else with the same problem I'm afraid never go to the bottom of this.

I sent it to OpenCockpits who were kind enough to run loads of tests but they could find nothing wrong with it.

My best guess is that I have a problem with one of my multi-gang power sockets. I'm told that if the power is interrupted long enough, or even dips a little through earth-leakage, SIOC can lose contact with the MCP.

The problem hasn't occurred since OC returned it so I can only hope that it's gone away.


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