MEP 805B display problem found.

[155mm]

I started to play with my 805b the other day, and notice some moisture in the display. Removed box from genny and took it to the shop to 'have a closer look' As I was carrying it to the shop, water was dripping out of the front glass, well thats not good.


Get to the shop, take the back off, and whoosh, I make a mess out of my shop table with about 2 cups of water that came out of the display. Well crapola.



The water was about 1" deep in the display box.



So I continued to disassemble the unit to hopefully salvage it and get things dried out so that it would function again. Get it all broke down, and find the display looks 'odd', so i disassemble the display.... ugh.... where the water stood in the box on the display it had broke down the plastic film in the display. Wonderful now I get to 'try' to find a display.



Lucky for me, the part number sticker was not damaged. Have not found a place in the US that will call me back, so Amazon from China looks the best bet to gamble on to try to find another display.

Moral of the story, if the plexiglass on the front of your display has any hint of moisture, IMMEDIATELY tear it down and reseal the front glass to keep the moisture out.

While the plexiglass is out is a perfect time to use some headlight polish on it to get rid of that 'dirty' look from any CARC overspray.

 

[155mm]

When I get my new display from China in about 2 weeks, I will do another write up to show assembly/disassembly for those of you who might need to do it.

 

[Korgoth1]

Thats another reason to prefer the a model

 

[baxter462]

Did your replacement display from China end up working well? If so, do you have a part number and vendor info available? I need to replace the LCD panel in one of my CIMs also. Yours is the color 2nd gen CIM, right?

 

[csheath]

These aluminum cases seem to promote condensation. My 803A had reset documentation in a sealed zip lock bag and it had about 2 cups of water in it. All the meters are corroded and rusted inside from moisture.

 

[155mm]

I did replace the screen with a China version but now I get this screen



if you cant read it.... it says

'Unbootable device available
r- reboot
s- setup
esc- bios debugger'

I did not use an exact part number replacement, the one I used was a direct replacement. So I ordered an exact part to replace it with, but I have not got to the tearing it down again. Hoping this weekend I can get some green iron time in.

 

[155mm]

delete please, double post

 

[baxter462]

Hello,

That makes me think your replacement screen is fine, but there is something wrong with the "computer" part of the CIM (the circuit boards on the inside of the back cover). Maybe the BIOS isn't set properly to boot from the internal flash memory drive, or the flash drive is bad/has corrupt software on it? Either way, I don't think another replacement screen will help. I wish more information was available on these CIMs so we could diagnose and repair them more effectively.

 

[baxter462]

Please delete

 

[155mm]

I wondered if there was a different driver for the different screens, only reason I got an exact pn replacement, see if that helps things, if not.... well i have a spare screen.

 

[baxter462]

Well, if you get time to play with it and swapping the screens fixes it, that'd be awesome! Keep us posted. I ordered an exact replacement screen for mine (thanks for the p/n by the way!). I'll give you an update on mine as well.

 

[bikeman]

Yeah.... that's a $10k part in the Army. Sealed unit. Got one back from rebuild that had a bad screen/CPU pack. Thankfully it was covered under warranty from Red River...

I'm guessing something happened to the actual computer portion of the panel. you'll need a programmer to look into it.

 

[155mm]

Luckily, I do have another 805B with a very good screen, looked new to me, so now to just find a computer nut to pull the fill out of 1 and put it in the other.

 

[155mm]

Well, if you get time to play with it and swapping the screens fixes it, that'd be awesome! Keep us posted. I ordered an exact replacement screen for mine (thanks for the p/n by the way!). I'll give you an update on mine as well.

When you get your new screen you will have to replace the metal back from the old screen to the new screen. Reason... there is a heater on the back of the old screen that was glued on and I couldnt get off. It was simple, six itty bitty skrews and 4 bend tabs. Also including a photo of the pn of the screen for anyone else that needs it.

 

[baxter462]

Thanks!

 

[155mm]

I did replace the screen with a China version but now I get this screen

View attachment 659114

if you cant read it.... it says

'Unbootable device available
r- reboot
s- setup
esc- bios debugger'

I did not use an exact part number replacement, the one I used was a direct replacement. So I ordered an exact part to replace it with, but I have not got to the tearing it down again. Hoping this weekend I can get some green iron time in.

OK, I have a head scratcher. This was the screen I got after replacing the screen, I had swapped CIM's with another 'B' that I have, and it worked just fine, so I stick the original back in, still no go, soooo it sits on the broke line waiting its turn to get back in the shop. I go out today trying to get a better pic of the error screen, turn on power, no screen. I am thinking, well crap, what now, so I pulled the CIM back out, oh silly me, I didnt plug in the cables. Hooked up the cables and turn on the power.... and ding, it starts up just like it is supposed to. So can someone with more brains than me explain why now it works?

The replacement screen is color, the 'new' looking CIM on my spare 'B' is only monochrome. OH dont mind the cracked glass, that was my dumb butt. Dropped a skrewdriver, so word of caution, the cover glass on these CIM's arent very hardy.

 

[bikeman]

Computer may just have needed to reset. Computers are weird. Make sure you keep the smoke in them. That's the most important part.

 

[Guyfang]

A CECOM rep once told me to always disconnect the cables on the CIM whenever it seemed to have a problem. Then try again. The few times I tried it, never seemed to help. But afterall, it is a computer, so a reboot could possibly help. Never know.

 

[SCSG-G4]

Disconnecting and replugging can remove corrosion by friction which is causing a poor connection. Remember, the voltages in computer circuits are low and the amperage is minuscule even compared to the voltage. Corrosion you cannot see will stop the flow of electrons from one circuit board to another (or short out pins on the same board). As was said before, don't let them get wet!

 

[baxter462]

I agree with the previous posts about poor connections and corrosion due to moisture. With the CIM case having been previously full of water, I'd suspect internal connections however, not the two external connectors. On the motherboard, the DiskOnChip (solid state "hard drive") is installed in a 32 pin dip socket. Since the error message stated it was unable to find a boot device, I'd remove the DiskOnChip from the motherboard, clean the socket and chip pins with Deoxit or something similar, dry it out, and reassemble. Make sure to take esd discharge precautions.