Long story short my PCM is fried, ended up buying a new one from wranglerfix. We sent it in originally to a PCM repair shop, they sent it back and said "broken tracer-CPU shorted beyond repair." I cant seem to find out what a tracer is and how that can lead to a short. We tried calling but theyve been terrible about answering. Anyone know anything about this?
Fried PCM
- Thread starter D M
- Start date
Not an electronics guru but I understand "traces" to be the flat conductive "wires" between components on a printed circuit board. But I would think they'd more commonly break open rather than short.
Thats what I would think. Except im almost 100% positive I dont have any shorts anywhere that would lead to that.
Im waiting on a call back, figured id ask here too and see if others had this issue
You don't need a short external to the pcm to cause it. It just happens sometimes as one possible failure mode of an electronic device. With what they're subjected to (temperature swings and mechanical shock/vibration) it's impressive they last as long as they do.
Circuit boards have traces, that's the copper crap that connects everything. Sometimes they are on one side, sometimes both, really nice boards have hidden traces sandwiched in-between the layers. Simple repairs are possible but generally things go downhill really fast anywhere near small components. I've fixed a few and tossed countless more. It's a normal thing to say the traces are damaged beyond repair, shorted or open doesn't matter. It really just means the circuit board is messed up. It's good @Wranglerfix is giving details, it's difficult to know what terms people are going to understand. It just sounds like the circuit board is busted to me.
Here is the inside a JTECH (97-04) ECM. The grey adhesive has to be gently pried open. A millimeter too far and the ECM turns into Elvis Patterson.
I have seen quite a few laptop and ham radio ribbon cables damaged during disassembly due to technicians not being careful.
The ribbon cable in the PCM circuitry is probably where the broken copper trace is located.
The ribbon cable in the PCM circuitry is probably where the broken copper trace is located.
lots of visible broken/cold solder joints on the backsides of the connectors pins. Is the whole PCB flex?
Old_Crow
TJ Enthusiast
I used to be a large-scale mainframe computer Field Engineer (repairman) in the 70's for Sperry Univac and I repaired more circuit board paths/traces and replaced more components and chips (IC's) on circuit boards than I can remember. Never had any problems after my repairs. And my paying customers paid big $$$ for their annual service contracts, they'd never put up with substandard repairs.
Old shit like this that had about as much computing power then as a good desktop computer does now.
Back when the only thing small was the computational power...
Old_Crow
TJ Enthusiast
Yeah, I've resoldered traces and connections on a lot of stuff that I couldn't otherwise replace when I had my restoration shop. Wasn't my favorite repair, but hey, sometimes there's no choice if you want something to work.
However, neither your repaired computers or my repaired dash circuit board for a '69 Road Runner are likely to be found busting rocks in Johnson Valley or Quartzsite so, on a Jeep, I'd go for a new board if it was available.
I love the smell of hot rosin core solder in the morning.
Especially when that rosin is surrounded by a lead/tin mixI love the smell of hot rosin core solder in the morning.