TIPM Question, Bob and Sag please take a look.

[mwilson]

Mike,



We're waiting to hear the diagnosis. Surely your shop has figured out the cause of the melted TIPM by now.

No, as of yesterday it was setting in the same slot as it was Friday. I did, however get a plea out to the District Service Manager asking for some help as this was a second occurance and lucky for this guy truck dealers operate a little differently than automotive dealers so packing a Sterling rather than a Dodge nameplate in this event is a help... .....



I am working from home today so I don't know if it is back in the shop or not.....



I will go scouting around in the morning.



Mike.

 

[HHhuntitall]

WOWSERS!!!!! I've NEVER seen one that smoked!!! That looks like it got struck by lightning!! What made it arc across the termials like that!??! Water?

I'm going to ask: How many cars he had jumped off that day?? A lot of tow trucks do offer that service... ... Water would be my next guess, as that's the worst I've ever seen one in a truck... . WOW!! I gotta show that to somebody!!

 

[pjorlando]

I saw the suggestion of water, was it salt water? I've seen this damage before on other printed circuits that were either immersed in or near salt water spray.

 

[jelag]

Mike... . I had an 08 5500 with a box we built for it... it had all kinds of lights... we built our own TIPM saver back when we took delivery... . We drove (company truck) for 140K miles with no problems... I can say we never tripped the TIPM but it only functioned to trip the relays... My personal feeling its a very weak point in the truck...



I can only assume you feel, as well at the guys at the factory that this is not supposed to happen... . I can only assume that the circuit protection inside the device is to protect it... . but than there wouldn't be all the failures we see.....



Gary... . Loved the pre-packaged smoke... . your on your toes... .

 

[Prairie Dog]

That damage is not caused by moisture on the board. The fabric of the board is exposed and the IC chip burned internally. It looks like it was driven by too high of supply voltage (Vcc), probably because the burning traces shorted to each other and applied 12V where it doesn't belong. But that parts a bit of a SWAG.
Either the circuit is driving too high of loads or the supply voltage for the components lost regulation and went way too high. I don't know where this power supply for this circuit is but it needs to be measured (5V, 3. 3V) before installing another board or it may do the same thing again.

 

[mwilson]

The story so far... ...



It got out of here without being gone over again. Last week was terrible as we are in the middle of vacation Hell. People missing all over the place. Even with careful coordination we have so many people packing 3-4 weeks vacation that summertime is nothing short of a horror show as far as trying to find people enough to do the job.



The two guys that know what I had suggested are on vacation this week so I had to start over.



So with that being said, I got the Service Manager (who was on vacation last week) in my office yesterday and went through this all with him. Showed him the baked, smoke releasing TIPM and told him that truck needs to come back before it burns itself up.

Told him that I suspect the trailer constant power feed and if need be, that flatbed may have to be removed if we can't find the issue in case it might be pinched over the fuel tank. This body has no outside means of attachment like u-bolts or bolt flanges. So maybe it has frame rail clamps on the inside of the body crossmembers which triples the chance of a pinched wire in my opinion.



Will keep you updated and will get pictures when the truck gets back here (hopefully under it's own power).....



Mike.