MikeOH

Do you have a name/contact info? Thanks!

As an EE I have to pipe in about PWMs vs. the stock dimming transistor. While very inefficient the transistor is virtually noise free (electrically); it ends up being like a rheostat and just dissipates power. PWMs can be quite tricky to design with low noise onto both their outputs as well as injecting noise back into the aircraft's power. I'd be REALLY careful with a low-cost PWM. YMMV.

Just replaced the exhaust gaskets on my M20F with IO-360A1A. I used the Superior SL77611 gaskets from Aircraft Spruce, P/N: 08-11999.

Gawd, this is a depressing thread

I wonder how labor vs. raw materials/out-sourced parts vs. interior vs. avionics breaks down. Maybe Mooney could build 'green' airplanes (airworthy) and owners could fly them to their interior and avionics shops as they see fit.

Sadly, can't say I didn't see this coming. Too few sold; too high price.

Not a doc, but there are TWO differences that come to mind vs. 'holding your breath.' One, you don't realize the oxygen is NOT in the atmosphere you are breathing and you breath it OUT of your lungs. Two, the partial pressure at altitude is very low (doh!), there's not as much O2 even if you do hold your breath it's not going to last 'as long.' I imagine these tables assume you are breathing, not holding your breath.

Here's my theory: You have a 'weak/intermittent' short to ground on the the #2 comm radio's PTT input. Something internal to the the PMA450 is providing a 'pull-up' path to the #1 comm's PTT input which prevents #2 from going to TX most of the time (i.e., when the 'short' is weak...when it is a 'strong' short to ground #2 transmits) AS LONG AS #1 has power. When you pull #1`s CB, that 'pull-up' is now gone and #2 goes to TX continuously. One way to check this is to put BOTH transmit (pilot and co-pilot) select switches to comm #2...my guess is that comm #2 will go to continuous TX as the pull-up path to #1 will likely be disconnected. You're wire wiggling pretty much confirms an intermittent short, and Jerry's suggestion to check pin 30 to ground (if you can get to it) is a good one. Good luck with tracking down exactly where the wire is shorting...NOT fun! You might look for where wire bundles come in contact/wrap-around metal structures, especially sharp edges. Could be inside a connector back shell...shield wire/foil contacting the back of a pin.

We are in violent agreement! I've don a poor job of making that clear, I guess! Your post is EXACTLY why I find these kind of threads so amusing...all this discussion about regulatory minutiae and documentation. All this agonizing over where to get 'approved data',...what the FAA will accept,...blah, blah, blah. Find someone competent, show them the old part, and let them make a new one out of the same material. The hardest part is finding someone competent... and that is competent enough to know when what you want is beyond his abilities.

Makes sense. Thanks!

Curious what you are using for safety? I was taught never to trust the O-ring in an hydraulic jack. Always used safety stands with cars, and aircraft jacks have safety wheels built-in.

Well, now that's the rub, "...if done correctly." So, if the plane's in annual, in theory, that should mean "it's done correctly." But, I think we all know that isn't really always true. So, the question becomes, after the fact, will the FAA and/or the insurance company do a deep-dive on the logs to determine that an OPP was NOT 'done correctly?' My point is that I'm a lot more worried about the insurance being denied than the FAA. I seriously doubt claims have been denied over illegal OPPs. Hence, my amusement with all the hand wringing over how to 'properly' produce an OPP.

Which was my point about being pragmatic

I read all of these 'arguments' with a bit of amusement. It seems to me the REALITY is if INSURANCE claims will be DENIED if the cause of an accident is somehow related to an OPP. Absent that evidence (denied claims) I will continue to take a pragmatic approach to properly maintaining my aircraft. The FAA and their after-the-fact interpretation take a distant second place to whether my insurance will be in force.

I'm pretty sure I do; I'll check next time I go the hangar. Thanks for the suggestion!

Yes, quite possible the intercom was out for some time prior. If I'm not having a squelch problem I don't touch it. Honestly, I'm hoping it's just a string of bad luck. Much preferable to tracking down intermittent electrical issues in a 50 year old aircraft! I'll crawl under the panel and see if I can ID some common ground points and check their integrity. Beyond that, I'm going to take a 'wait and see' approach absent any other suggestions. Thanks, all

Hi Greg, Thanks for responding! Yes, at the moment, everything is working (except for the intercom that I haven't yet replaced/fixed). The Garmin, G3, and intercom are all on the CB switched Avionics buss. Nothing else has burned up....so, far. I have no idea if those items share a single point ground...and, no idea how to track that down...many wires, all white, bundled together, buried behind the panel and, I'm not sure my back is up to the task Does the electrical system have any (effective) overvoltage protection system? Probably well before the days of transorbs and the like, but curious if the system is 'clamped' at some voltage. What kind of spike could occur with a temporary VR/alternator failure? Thank you!

"Your papers, please!" And, you are here to tell us that is, "a total non-event," and are, apparently, only too happy to comply with gathering them all up. History is lost to many, I'm afraid. Sad

Well, I'm going to be mean...Too Stupid for Arby's (They advertised jobs on pizza boxes for gawd's sakes!) (But, I'm nice to 'em, too. They can easily make my life more miserable than going through airport security already is)

Good to know! I suspect mine have been neglected...annual coming in December.

Hmm, must have taken out the sound-proofing by the time Mooney built my F

What Garmin provided with the repaired unit left a LOT to be desired. In it's entirety: "Verified problem. Replaced main board and display lens. Tested and met all specifications." Pretty disappointed. Never flown in rain. Never washed with water (use Wash-Wax-All). Yuup. I'm hoping one of the avionics guys here will see this thread and take pity on me

No reason to. The G3's ONLY electrical system monitor is system voltage. And, as an EE, and as previously stated, there are NO clues in the system voltage as far as what the G3 records: stable at 13.8 volts right up to the point where the G3 'froze.' Subsequent downloads show the same stability. If this is NOT just coincidence, then it's a transient event whose source remains a mystery.

Thank you! That's the kind of 'out-of-the-box' idea I was hoping for. I'll check that out.

Well, I have been flying since with no issues. And, I have pulled the G3 data with no anomalies seen. G3 is at its highest sampling rate, but that's not going to capture micro, or even milli, second transients. Never any popped CBs, or over-voltage indication. Absent that, I'm not concerned with fire, but with more failed avionics. While I appreciate the suggestion, taking it to a shop with NO presenting symptoms sounds like a great way to spend hundreds, or thousands, of dollars looking for ghosts. I am a practicing EE, so it's not like I have no background. But, yes, some intermittent in the VR/alternator system would seem plausible; was hoping someone here had seen and fixed the same kind of problem. I brought up this over-voltage theory with the avionics shop I took the blown GN430W to, and the owner seemed to think that was HIGHLY unlikely as the WAAS models are universal input (switch-mode power supply) good up to something like 40 volts. Anyone know what voltage an alternator can reach? Also, isn't there an overvoltage 'clamp' in the system?