MFD issues on '04/'05 Prius

[xunkn0vvnx]

Ok, I took the advice of the members here on the board and completely disassembled my MFD unit. The problem is:

I CAN'T FIND WHAT BOARD PIN 60 IS WHERE THE SOLDERING RE-FLOW NEEDS TO BE DONE.

Please help, I am using Hobbit's instructions and my car is literally in pieces. Which board does the repair need to be done to? I found a number 60 but it looks nothing like the one in Hobbit's pictures. Can somebody please help? Pictures would also be greatly appreciated. Thanks!!

[maseace]

It's a small rectangular connector in the middle of the board directly behind the LCD screen (the half that connects to the LCD screen board). The pins are very small and 59 and 60 are at one end of the connector.

My repairs only lasted a few months each time, so I ended up buying a newer used MFD on eBay for a little over $100 (the revised part number that fixed the connector problem).

[northwichita]

I followed Hobbit's instructions preceding the 60 pin repair, which were to
A pass with DeOxIt and several plug/unplug cycles seems
to clean all this right up, though, so I wouldn't say
the connectors are outright corroded.

This is for the main connection between the two circuit boards.
I put it back together and has been running fine this last
month.

Intermittent MFD display fixed with cleaning circuit board connection.

If you've already done this step then I just wanted to remind others.
If you don't see a break around that pin 60, perhaps it is somewhere else.

[xunkn0vvnx]

After I took apart the MFD display and literally strained my eyes just trying to find the microscopic pins, I decided to just spray electrical cleaner rather than taking the soldering route. I would rate the soldering job expert and by no means a novice leveled task. I would be much more comfortable having the board worked on by somebody who has experience with this issue and not just a random electronics shop.

I reassembled everything and so far so good, the electrical cleaner did the trick. As for how long it will last, only time will tell.

[jayman]

I'm wondering if the *real* reason why the combi meter display (The speedo, fuel gauge, PRND display, etc) fails is due to corrosion on one of the 4 connectors?

Folks have had the combi meter replaced, and naturally everything worked. I wonder if just disconnecting and reseating the connectors would have done the same thing?

I've had enough experience with that problem working on military electronics, especially communications gear, and industrial sensors in harsh chemical environments

[xunkn0vvnx]

UPDATE: I cleaned the connectors and the problem returned today. But what is interesting is that the problem only exists upon startup and only lasts for 30 seconds or so.

[artie]

Sorry to hear that, I guess the connections will need soldering and good luck to "permanently" cure the problem.

[ButchDeal]

Just had the problem on my '04 but with 157k miles I didn't think I would get any place at the dealer so I used Hobbits instructions to take it on. Dash disassemble was not too bad at all (done some of this before for lockpicks).

I used my camera to take this close up shot were you can clearly the the cracks. I made a fine point solder iron with a wire like Hobbit suggested and re-wetted all the points on this side. Worked perfectly.

[patsparks]

Originally Posted by jayman

I'm wondering if the *real* reason why the combi meter display (The speedo, fuel gauge, PRND display, etc) fails is due to corrosion on one of the 4 connectors?

Folks have had the combi meter replaced, and naturally everything worked. I wonder if just disconnecting and reseating the connectors would have done the same thing?

I've had enough experience with that problem working on military electronics, especially communications gear, and industrial sensors in harsh chemical environments

<edit> I need to learn to read peoples posts properly. What I have written below relates to the MFD not the combi-meter or upper display. Oops!<end edit>

I'm wondering if the reason people have had limited success with disassembly, clean and reassemble is because they are closing the gap in the cracked solder when reassembling? I suspect this to be the case. There is no doubt that the solder connection cracks. No point looking with the naked eye and no point running to the shop to buy your first ever soldering iron to repair this. If you have never done fine soldering before, a $1000+ part is not where you should be learning this skill. A tech skilled in repair of small circuit boards like those in laptop and PDAs will have the skill to do the repair. I saw mine under a microscope and the repair was beautiful. If your repairer does not have a microscope chances are he cant handle the repair. However just because he does have one doesn't mean he can though. I know a very crap mechanic with a full Snap-On tool kit!

Also be mindful of reassembling the MFD without putting any twisting loads on those plugs.

I'd wish everyone luck with this but it isn't luck you need, just a skilled technician.

[jayman]

In the case of the MFD, we know there is an issue with poor factory soldering. With the combi meter, we really don't know yet