Master switch replacement

[cliffy]

Training is this case can be just referring to the the maintenance manual  That would suffice the training level of scrutiny because of similar tasks on other small aircraft.

If one is talking about composite repairs to a wing on a Cirrus and all the experience has been working on Cessna 172s then more formal training would be required.

Required training is a broad brush outside of a 145 Repair Station. 

[EricJ]

15 hours ago, corn_flake said:

@cliffy Points well taken.  But than again, A&P are also not suppose to perform any repair or modification if they have not been trained.  How many time have we all seen A&P working on a Mooney when it's the first time they ever seen a Mooney in their life.     yeah.... discretion... 

When I went to A&P school they pointed out that by the time we got done we'd pretty much touched an example of everything, and if I ever got challenged on this it'd be likely I could just say, "yeah, did that in school." 

[tony]

On 12/18/2021 at 9:45 AM, goalstop said:

So it looks like I'm having this issue in the E-model (short story - likely corrosion on the master switch creating a seance in the cockpit): https://www.donmaxwell.com/fluctuating-ammeters

She's going in for a total panel upgrade in a couple weeks, but looking on LASAR, it looks like every single master switch for a Mooney is sold out.

What is one to do?  Are there other master switches that are certified for an M20E?  Does anyone know of alternate sources to find a master switch?  Are there other more standard master switches that are certified for a Mooney?

Thanks for the help!

If your E model is like my F model, the only thing the master switch controls is the master relay.  It completes the coil circuit to ground.  Go to the master relay with a jumper and complete the circuit to engage it.  If you don't know what I'm talking about, best you get someone who does because if you do it wrong you may start a fire.  If the "seance " continues, its not the switch.  My guess is there is nothing wrong with the switch or the master relay.  You probably have old, corroded circuits breakers for your avionics.  

[Yetti]

On 12/23/2021 at 12:08 PM, tony said:

If your E model is like my F model, the only thing the master switch controls is the master relay.  It completes the coil circuit to ground.  Go to the master relay with a jumper and complete the circuit to engage it.  If you don't know what I'm talking about, best you get someone who does because if you do it wrong you may start a fire.  If the "seance " continues, its not the switch.  My guess is there is nothing wrong with the switch or the master relay.  You probably have old, corroded circuits breakers for your avionics.  

Very rare condition for a circuit breaker.   They are almost always binary.

[ArtVandelay]

Very rare condition for a circuit breaker.   They are almost always binary.

I had a defective CB, it would let current pass so radio would work, but it kept crashing. After replacing the radio, they figured out the CB was causing the voltage to drop and the failures. It was a new CB so must have been a manufacturer defect.

[Yetti]

1 hour ago, ArtVandelay said:

I had a defective CB, it would let current pass so radio would work, but it kept crashing. After replacing the radio, they figured out the CB was causing the voltage to drop and the failures. It was a new CB so must have been a manufacturer defect.

That's why I did not say never.   And like you it was a single CB   He is describing multiple issues.   Now I doubt it is the master switch as that would just make the master relay cycle if it were bad.   I would be looking more at the Radio master relay since pretty sure they are underrated.

[Prior owner]

FYI- The master switch also controls the generator field circuit in the older planes.  Not sure that’s his problem though…

[goalstop]

Update on this one - discovered that the master battery solenoid / contacted was corroded and finally failed. Also replaced the battery. Will see if that fixes the issue… if not we’ll go after the relay next! At that point I’ll have an all-new electrical system

[A64Pilot]

On 12/20/2021 at 6:25 AM, cliffy said:

There is an AC that covers what parts an be installed on a "certified" airplane and included is AN, MS, Space Qualified, among other designations. 

Technically speaking even the little 1/4" audio switches that some use that used to come from Radio Shack (and are still carried by Spruce) unless they have the AN or MS qualification they can't be used. 

The above referenced MS switch is a direct replacement for the Parts List called for AN switch. 

Here you go AC 23-27 as an A&P IA I reference it in the logbook entry if I have to use parts I got based on actual part number as opposed to Mooney Aircraft part number.

ALL Mooney meet the definition of “Vintage” for this AC

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_23-27.pdf

‘In my case it was landing gear solenoids, one used on my Mooney are actually golf cart solenoids and widely available, Mooney part number one I could only source from a junkyard and at insane price, like $1,000 or so and then you have an old solenoid of unknown condition.

Golf cart / winch solenoid. 100 amps continuous duty $30 on Amazon

40 yr old Mooney solenoid on the left, new golf cart solenoid on the right, both identical part number

 

[flyboy0681]

2 hours ago, A64Pilot said:

Will this work?

 

[MikeOH]

8 hours ago, A64Pilot said:

Here you go AC 23-27 as an A&P IA I reference it in the logbook entry if I have to use parts I got based on actual part number as opposed to Mooney Aircraft part number.

ALL Mooney meet the definition of “Vintage” for this AC

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_23-27.pdf

‘In my case it was landing gear solenoids, one used on my Mooney are actually golf cart solenoids and widely available, Mooney part number one I could only source from a junkyard and at insane price, like $1,000 or so and then you have an old solenoid of unknown condition.

Golf cart / winch solenoid. 100 amps continuous duty $30 on Amazon

40 yr old Mooney solenoid on the left, new golf cart solenoid on the right, both identical part number

 

Just be careful with this...they may look the same and have the same P/N but without looking internally you can't be certain.

I had this happen with an automobile fuel pump relay: the factory one lasted over 100K miles, and I put in an aftermarket (Amazon) with the same P/N and it lasted about 2 weeks.  Stupidly, I bought another and 2 weeks later it failed, too!  Finally, paid the dealer $50 for a factory part (instead of $15 for the Amazon ones) and haven't had another problem (another 100K miles and going).

Took the old factory part and the Amazon 'equivalent' apart and internally they were completely different!  Small cheap non-precious metal contacts and small gauge wire in the relay coil compared to beefy wiring and large platinum contacts in the OEM part.

[N201MKTurbo]

28 minutes ago, MikeOH said:

Just be careful with this...they may look the same and have the same P/N but without looking internally you can't be certain.

I had this happen with an automobile fuel pump relay: the factory one lasted over 100K miles, and I put in an aftermarket (Amazon) with the same P/N and it lasted about 2 weeks.  Stupidly, I bought another and 2 weeks later it failed, too!  Finally, paid the dealer $50 for a factory part (instead of $15 for the Amazon ones) and haven't had another problem (another 100K miles and going).

Took the old factory part and the Amazon 'equivalent' apart and internally they were completely different!  Small cheap non-precious metal contacts and small gauge wire in the relay coil compared to beefy wiring and large platinum contacts in the OEM part.

Yes, the cheap ones on Amazon are Chinese knock offs. I had one go bad and found a new old stock from the original American manufacturer.

[A64Pilot]

On 12/28/2022 at 11:25 PM, N201MKTurbo said:

Yes, the cheap ones on Amazon are Chinese knock offs. I had one go bad and found a new old stock from the original American manufacturer.

I think you’ll have a hard time finding actual US made electrical or electronic parts.

I believe but aren’t sure Kissling relays may be US, but unfortunately they don’t make this part number relay, Form and fit is different for what they make, so while I’m certain it’s s better relay, I don’t have an approval basis to use one.

Used to be I’d only buy Timken bearings, because they were US made and higher quality, but I don’t believe anymore, even Japanese bearings aren’t usually Japanese. In 2010, the only Toyota you could buy in the US that was made in Japan was a Prius, all others weren’t made in Japan

So unfortunately even better trusted US name brands are often just reboxed products made in China.

[Pinecone]

China can make high quality parts.  It depends on what the customer specs and the QC they do on the parts.

[A64Pilot]

10 hours ago, Pinecone said:

China can make high quality parts.  It depends on what the customer specs and the QC they do on the parts.

Yes in years past Fred Ayres had some kind of deal with China, they manufactured flight controls, he shipped the materials etc to maintain traceability. 

When Thrush opened up there were still quite a few of those Chinese flight controls, they had a very high quality of workmanship, perfectly driven rivets no dents etc, frankly better than our in house flight controls.

With China you get what you pay for, and have quality controls to verify.

There are many articles that claim the Chinese Tesla’s are manufactured with fewer defects than the California built ones.

Remember when Japanese meant cheap junk? 

What I think it is more than anything else is greed, the US purchaser is often only concerned with how cheap can I get it, and they get what they paid for, why do you think US brand name products are sourcing from China? I think greed.

[Fly Boomer]

16 minutes ago, A64Pilot said:

Remember when Japanese meant cheap junk? 

Yes, but my Japanese-built Prius has been bullet proof.  150,000 miles and the only thing I have done is put on tires (one set) and I somehow killed the boot battery.  The "boot battery" looks like a motorcycle battery, and about all it does is boot the computer when you start the car.  Then you have all the juice in the 500-pound battery available.

Factory wiper blades.  Factory brakes.  Factory air in the tires -- okay, that last one is an exaggeration.

[A64Pilot]

On 1/1/2023 at 8:18 PM, Fly Boomer said:

Yes, but my Japanese-built Prius has been bullet proof.  150,000 miles and the only thing I have done is put on tires (one set) and I somehow killed the boot battery.  The "boot battery" looks like a motorcycle battery, and about all it does is boot the computer when you start the car.  Then you have all the juice in the 500-pound battery available.

Factory wiper blades.  Factory brakes.  Factory air in the tires -- okay, that last one is an exaggeration.

Ours had 270,000 on it when we sold it and didn’t burn a drop of oil. Gave it to our Daughter as her College car and she was driving it hard, warped brake rotors etc.

Toyota doesn’t require it but it’s best if you change the PSD “transmission” fluid and engine and inverter coolant and plugs at 100,000 miles

The Toyota 12V battery isn’t very good, usually it’s killed by not closing the trunk completely, that’s how I killed mine, but buy the Optima deep cycle and it’s likely you’ll never buy another. The Prius battery has odd sized terminals so a regular battery won’t fit, you could change wire terminals, but just buy a battery that fits

[Fly Boomer]

1 minute ago, A64Pilot said:

Toyota doesn’t require it but it’s best if you change the PSD “transmission” fluid and engine and inverter coolant and plugs at 100,000 miles

I did both of those things.  I said earlier I had done essentially no maintenance, but I forgot about the plugs.  I consider the coolant change just good sense regardless of what Toyota says.

[A64Pilot]

Toyota does spec coolant change, I misspoke, but they don’t the PSD fluid, it’s a simple job, but I had to talk the service dept into it, and yes it’s PM, not a repair