Pop goes the A/P

[DVA]

I'll take a stab at it:

1. The pop you heard was an electrolytic capacitor C222 as we predicted. It was also the culprit that leaked out the smoke; you saw that on your pictures.
2. They found a broken trace, which is a connection on the Printed Circuit Board, that connected diode CR231 and Resistor R213; this could have happened at anytime, but it was likely due to the cap's container sliding across the PCB when it popped and moved. (that's just a hunch on my part, traces normally don't just "open up" on thier own.
3. They found a shorted transistor Q216, again, this could be collateral damage when the cap failed. Or it could have been part of a circuit that is normally unused in normal conditions, like an alarm circuit or a limit circuit, so you would have never noticed it.
4. I don't know what SA-106 is for, but I suspect a Service Advisory for something important was performed.

Good news, this should have been relatively inexpensive. Was it?

DVA

 

 

[flyboy0681]

Depends on your definition of inexpensive. 1AMU, $60 for parts and 8 hours at $115 per.

I guess I should be happy that the parts are still available, given its age.

[DVA]

Just now, flyboy0681 said:

Depends on your definition of inexpensive. 1AMU, $60 for parts and 8 hours at $115 per.

I guess I should be happy that the parts are still available, given its age.

That's about what I expected. You've never had a 5grand AP repair?  Just ask around.

[flyboy0681]

3 minutes ago, DVA said:

That's about what I expected. You've never had a 5grand AP repair?  Just ask around.

Since you called this one exactly, I now have a better comfort level that the 8 hours was realistic.

Is it your belief that this was all the result of 35 year old components and nothing external?

Thanks for the help.

[DVA]

6 minutes ago, flyboy0681 said:

Since you called this one exactly, I now have a better comfort level that the 8 hours was realistic.

Is it your belief that this was all the result of 35 year old components and nothing external?

Thanks for the help.

On the 8 hours: that's just a day of work for one person. Taking 8 hours to do what was on the work order was reasonable. Those are complicated devices that used hundreds of discrete components to control the ship.  Today those hundreds of R's and C's and CR's and Q's and L's are replaced by a single chip the size of your fingernail, on a circuit board that cannot be worked on at the component level. Instead, they just replace the whole board in many cases and as a result this flipped the labor vs parts ratio. 

To fix your older A/P you had $920 of labor and $60 in parts. The tech that worked on your A/P needed time, real electronic theory knowledge, real troubleshooting skills and real experience in PCB repair techniques; it's a lost breed of talent.

To compare, a friend just had a newer GNS750 repair that was $1500 in parts and $180 in labor. It was troubleshot by looking at an error log - 20 minutes of "work" - the error log printed out to the tech exactly what module to replace. So, remove the failed module, slide in a new one, and 20 minutes later its done.

While YOUR tech "fixed" your problem - The other tech simply did a "repair". There is a big difference.

And Yes, I have no reason to believe from what you have written that anything external would directly cause this. I've been married for as long as that cap lasted, I know how hard it worked over the years to keep your plane happy.

DVA

 

[Mcstealth]

On October 11, 2016 at 8:51 AM, aviatoreb said:

Im sort of surprised to see integrated circuits - I was almost expecting to see relay switches, vacuum tubes, rubber bands and gerbils inside old school avionics.

The Gerbils were replaced in '82. Fanboy's J is an '83

[StevenL757]

On 10/1/2016 at 8:22 AM, daver328 said:

You should've never started letting airline pilots get in your Mooney. Especially don't let them touch anything!  (You asked for "wild guesses" .... ;-)

Yeah, they're a bad omen...especially the Southwest guys.  ;-)

[whiskytango]

I once knew an electrical engineer who said that electrical equipment should be operated like oil-fired steam boilers: adjust for minimum smoke.

[Danb]

DVA..Dave agreed a very reasonable cost compared to most A/P work I've had done like the rest of us.

Dave I was wondering if your brain hurts? All that knowledge you spill out is awesome.