Control Resources Monitor Panel MDS100

[Gayden.Peel]

When we purchased our coach the monitor panel wasn’t working. It looked like somebody had added a switch at some point or maybe that was from the factory. It’s hard to tell with the way it’s wired today. Naturally Control Resources is defunct now and I didn’t want to ship it off to an electronics repair service until I had a go at it. I searched around the site a bit and found some references to the technical information about the monitor panel wiring plug. This has the breakouts to the sensors and power reference in and out. When I opened the monitor panel up I did find some residue that had leaked out of a few components so it looks like at one point there might have been a power surge to it and maybe have blown up one of the capacitors. I ordered some new capacitors and a new transistor which was a TIP 30 C and proceeded to remove and replace the new components. After swapping those out the monitor turned on and read some values. I performed  the calibration reset and it seems to run thru its paces. Some of the values are off so there might still be some components that are messed up. I will go through and test the rest of the capacitors. There are some other suspect Components. Here are some pics for reference.

[Gayden.Peel]

This MDS100 panel has a lot of character with its vintage glass surface and capacitive touch buttons, so if I can make it work then I'd love to keep it since it matches the Magnum IntelliDrive System. If I continue to get weird readings from it after going back thru the components then I might search for a replacement. Most of the ones on the market are very lack luster and are simple membrane pad with led indicators. An LCD touch panel would be neat to find.

[Eric Maclean Co-Admin]

Gayden
It obvious you have some electronics experience
I believe that panel arrangement is 12volt dc feed as such it may have at sometime been reverse polarized by someone working on the battery banks.
The fact you got it up and running is a good step.
As with all vintage electronics of this age those electrolytic capacitors will be or have aged out developing a lower ESR which can mess with calibration of the circuit and effected readings.( The leakage on that electrolyte capacitor in the picture is evidence of this).
I would also go through and check all the transistors as they too can develop age / heat related problems.
I would also check the diodes in the system as a reverse polarity could have wipe one out somewhere .
Also be careful to control static as many of those ic chips will be static sensitive.

If you end up looking for another unit you could try here

https://usedrvparts.visonerv.com/

Looks good great work
Good luck
Eric

[Gayden.Peel]

Yeah last night late dodging freezing rain running back and forth to the rig I was able to "test" the unit out lol. Leg 1 and 2 disagree on the input AC voltage, one says 142V one says 138V, neither of these would be correct, so I agree, something is throwing this value off. With the input DC voltage its reading almost 18V, which I checked, it was closer to 13.2. The tank levels seemed to be correct, but who knows if it was a fluke. My coach no longer has solar but when you select the solar button it comes up with "Full" lol no actual reading. I suspect more bad caps, There looks to have some more recurring "custom" wires, there are two 4 pin Bosch relays electrical taped up spliced into the wire harness. I couldn't find a reference to this on the Beaver wire schematics, so who knows what else was wired in or borrowed from this source. I was going down the minimum viable product just to see if it could come back to life. Next is get it right It's nice to know that there, fingers crossed, might be a place to order another old unit. I want to make a breakout cable for it that I can control from my bench to test with, might order that next.

I really appreciate the level of response from you and this forum in general, honestly forums have kind of gone out of style on the current interwebs in leu for Facebook groups. I grew up dealing with message boards, so I am so excited this group is active here.

Thanks!

[Eric Maclean Co-Admin]

Gayden
I agree forums and the useful information they provide are slowly disappearing.
The key to making a forum vibrant and relevant is the input we all contribute each of us has a skill set and collectively that is vast.
For instance I'm sure that there is more than one person out there with the same monitor panel as your with similar issues watching this thread
In hopes to gain understanding and even a possible fix for their own.
Please keep us up to date and in the loop it's people who make this forum relevant and vibrant people like you
Welcome aboard

BAC forum Co-administrator
Eric Maclean.

[Eric Maclean Co-Admin]

Gayden
In the picture of the circuit board I see in the top left corner a gold colored trim potentiometer do you suppose it's there to calibrate those meter readings?

[Joel Ashley]

Hayden, I don’t know if you ever resolved your PCB issue.  I regularly go into a circuit board searching for a faulty component, and have “fancy” tools, like LCR tweezers.  But an essential tremor confounds many of my soldering escapades with minuscule solder points.  And I’m minimally conversant in electronics despite multiple books on the subject.

I know this is late to the party, but if I couldn’t ferret out a problem with a board from our coach, I’d consider sending it to M&M, or at least consulting them:
https://www.mmrvelectronics.com/

Joel

[Gayden.Peel]

Hayden, I don’t know if you ever resolved your PCB issue...

I did for the most part, It shows some of the levels and such, the screen is still a bit dimmer than I would expect considering the CAT Engine Display which seems to be made by the same company is very bright. I would love to get it back to 100% but other issues on the coach are plaguing me as of late. Thanks for the link, I might look into it and see what they think. 

[Joel Ashley]

The only issue with M&M is they understandably prefer to see the device installed, so they can best analyze its behavior.  That commonly entails taking the coach to them.

Joel