New re engineered flight system PMD

[bison]

mine acted like it was soldered to the plate. I couldn't find/see the thin strips your talking about

Here ye go,the wire are no thicker than a single strand from a 16 and 18 gauge multi strand wire.

 

[bison]

Ah, I see.

I was just being too "subtle".....

i think so.

i "gently" dismantled this one today with a BFH

the best attempt sofar.
The four long leads in the first pic are the transistor connections,
there is one screw holding the chip to the base(center of 3 holes bottom of chip) left lower pic,the other 4 holes are transistor bolt holes.

 

[Bigburban]

Could they have figured this out before I just ordered a new one!!! WTF! My old one lasted 1yr and 3 months I called the Dipaco number someone posted on here and they acted like they could have gave a rats azz less about the PMD or my problems with it.

Buddy didn't you mention something about electrical problems being a possible cause?

Are they referring to grounding the heat-sink as another precaution or not grounding the heat-sink?

The one I got in the mail today from Leroy says 1-13-2011 wonder if it is the new design? Anyway to check to see?

 

[buddy]

The person on DP was claiming they take the extra precaution to make sure the sink does not get grounded, even though they isolate it internally. But claims that grounding it would resolve the issue he described.

I am not sure that person was completely familiar with the redesign, but the failure mode makes sense. I just dont understand why they dont just ground the sink and solve the potential for the transistor collector shorting to it. That would make too much sense I suppose.

 

[JMJNet]

"Simplicity" is not common sense sometimes. Every designers want to design fancy instead of simple.

 

[NVW]

i "gently" dismantled this one today with a BFH

I wonder if you put one in the freezer before hitting with the BFH if it would help separate things?

 

[bison]

If you hit it hard enough it won't need freezing

 

[WarWagon]

Here ye go,the wire are no thicker than a single strand from a 16 and 18 gauge multi strand wire.

This is the inside of the power transistor.
If I was to guess I would suspect cracked solder joints first then in the photo above the silicon transistor material cracking or failing. Transistors go bad all the time. (See avionics repair logs that read "replaced transistor Q3" and the like.) Heat and heat cycles both contribute to their demise. A light bulb that is run 10% cooler has double the life. Same goes for other electronics and add to this: the cooler it runs the less expansion and contraction it has from room temperature to hot and back. That expansion and contraction is like bending a paper clip so many times before it breaks.

Some hard drives were recalled for a bad chip that would get hot and quit. Cooling it down allowed the bad chip to work again for a short time.

This make me think the transistors themselves burn up internally likely by cracking.

EMI noise is just a bunch of BS! Because once a circuit is noisy it fails and stays dead. Heat may increase the noise but that would just drop the solenoid close confirmation.