My sleeping aid. A long story about a shorting circuit. (??)

[DaV8or]

OK, it's a long one. It's a story about why sometimes it costs so much to repair an airplane. It's not always the government's fault.

 

So I have been having trouble getting my engine started. So much so that I had stopped taking my airplane anywhere where I might shut the motor off. When it did start, I would just fly around the patch and then return home. Not entirely what I had in mind for a private airplane.

 

My fuel system has been rebuilt top to bottom on my watch. Completely IRANed fuel servo, rebuilt flow divider, new injector lines and now GAMI injectors with only about 40 hours on them. When I prime, I see a positive fuel flow. When she won't start, I get out and can smell fuel in the exhaust pipe. I'm pretty damn sure lack of fuel supply is not my starting trouble.

 

She gets a new Bracket air filter every annual and this one is now about 40 hours. My compressions are all good. She can breath and compact air with the best of them. This just leaves the spark.

 

Yes, I have Champion massive spark plugs. They have about 80 hours on them and have all been resistance checked. All good. I thought a good place to start might be my mags as they are Slicks and right at the 500 hour mark. According to the internet, Slicks are total POS and likely will need total replacement so why don't I just buy some Bendix mags, right? Well, we'll see about that.

 

So I pulled my mags and my harnesses and sent them up to Aircraft Magneto Service in Washington. Great people, got great recommendations and competitive prices. They did the inspection and sent them back. End report- nothing really wrong with them or the harnesses. I got off cheap and they hardly replaced anything. It turns out that Slicks can survive 500 hours of use after all.

 

Well this kind of sucked. I wanted them to find something wrong. I desperately wanted that "Aha! Here's the problem!" moment.

 

No such luck. 

 

So I put the mags and harnesses back on but still searching for that "Aha!" moment. I pondered the ignition switch, the wiring and the starting vibrator. Speaking of which, I had no idea I had Shower of Sparks ignition system on my plane. Some mechanic somewhere installed it in my brain that I had an impulse coupling and I had never seen, nor heard a ignition vibrator on my plane, so never thought more of it. When I removed the mags, I discovered otherwise.

 

So where is this vibrator they speak of?? It turns out Mooney put them up high on the firewall, on the cabin side. Back in the day this wasn't such a bad place, but on any vintage plane with the 201 windshield conversion, this is the absolute worst place to put it! No wonder I never saw it! You need ESP and X-ray vision to find it.

 

How come I never heard it operate before? Well, it turns out I don't have a starting vibrator after all. Wait, didn't I just say I did have a Shower of Sparks, retard ignition system??! To my surprise I actually have a Slick Start solid state electronic booster that replaces the vibrator. It makes almost no noise when it operates.

 

Here's what the Slick Start looks like with my X-ray vision on-

 

 

I tested the Slick Start by disconnecting the starter motor, putting the prop at TDC on number 1, placing the bottom spark plug lead next to the cylinder head with a sizable gap, turning the master on and turning the key to start. Wow! ZAP!! That thing sure makes a big spark! So it makes a spark, but that's not to say that it still might not be defective somehow. More testing is needed later.

 

So with the Slick Start being almost impossible to access and the same being true for my ignition switch, I thought I would conduct a little continuity test with the wires I could get at, the P leads. A quick right P lead to ohm meter to ground connection verified that the right side of the ignition switch was working perfectly.

• Off grounded.
• Right, ungrounded.
• Left grounded.
• Both, ungrounded.
• Start grounded.

However the same check of the left P lead showed that the left mag, (you know, the one that starts the engine?!) to be grounded in all ignition positions!! That would certainly make it hard to start. Bear in mind I conducted these tests with the mags disconnected from the P leads, so there was no issue with the mags in the circuit.

 

So before I tackled the daunting task of gaining access to either the ignition switch, or the Slick Start, I decided to call the Slick tech support at Champion Aerospace just to see if there was any way that this grounded condition was normal for a Slick Start and maybe I was just doing the test wrong... or something.

 

No such luck. He said the Slick Start would not cause this situation. He also confirmed what I suspected, that the guy who installed the Slick Start didn't follow directions and installed it his own way. I have no F'in idea why!!! By doing so he made it really hard on himself and now me! The Slick Start is supposed to be mounted on the firewall on the engine side and connected directly to the mag and not have anything to do with the ignition switch. Because I wasn't sure exactly how it was wired, the tech support guy suggested I start with the ignition switch. He said that if not connected right, the Slick Start can fry the Bendix ignition switch eventually. Besides he added, "When was the last time that switch was changed?"

 

1975. According to the logs. Sleepy yet? No? read on...

 

OK, so the switch is coming out, but how? I thought if I just popped the headset jacks out below the switch and removed the switch bezel, it would squeeze out the little hole and down low enough to get at the wires. No such luck. The wires aren't anywhere near long enough to do that.

 

Then I thought that I could just unscrew the turn coordinator (actually an S-Tec 30) from the panel and push it back so I could get at those wires through the hole. Sorry Charlie!! That S-Tec bumps right up against the airframe tubing in this installation. The only thing left was to remove the metal panel from all the instruments then I could finally get at this little bitc... I mean switch.

 

Front seats out, pilot's side wall panel off, whole radio stack on the back seat, a zillion screws and a couple of custom wrenches to get at the idiot nuts on the backside of the panel later, (a whole other rant! ) the panel was lose and instruments flopping about freely. Now I should be able to get that S-Tec out altogether. After disconnecting the multi pin connector on the back of it I thought I was home free.

 

Denied!!

 

As I tried to ease it out of the rat's nest, I then discovered two itzy bitzy wires that have no plug that run the little light inside. The other end of those wires disappear into a wiring bundle as big my arm with about 2,000 zip ties holding it tightly together. At this point I would start banging my head on something, but I had already done that enough working under there!

 

Finally, I got a break. It occurred to me that I could now push the S-Tec backwards with the connector off and everything lose and sloppy and then flip the switch up and over another wiring bundle and have it hang down where I could access it. It worked!!

 

The sky cleared, trumpets sounded and there it was!

 

 

After fully documenting where all the wires are attached with photos, labels and a drawing, I finally had the 40 year old switch out on the bench. It tested... perfect. No problems. AGGGGGGHHHHH!!!! Why o' why could it not have been a melted, crumbling mess of plastic and tin??!!

 

I can tell you all are starting to nod off, so my work here is almost complete, so I'll make it shorter. Initial tests of the P leads show there are no shorts to ground. I had to go home and the other wires have not been investigated yet. It now turns into a game of- "Well, since we're in there..."

 

I am considering installing a new ignition switch anyhow (about $410! Ouch!) , new P leads, a new landing gear switch as it is original and now pushing 50 and relocating the Slick Start to the correct placement and wiring as per instructions. I think I'm also going to go to the Tempest UREM37BY plugs too.

 

So, out of pocket expenses haven't been too bad so far. Only about $700 for the mag inspection, but if I were charging for the labor... well it would be climbing. These airplanes are not designed to be worked on. At all. Period. For those still reading I have to say...

 

To be continued...

 

[ELT]

Hi Dave,

I know your pain.  After an annual my E turned over good but would not fire.  60 hours on a fwf.  We replaced the switch twice, SOS vibrator, replaced points in the SOS mag even if it was only 60 hours old, checked everything, replaced p leads.  Finally sent the starting mag back to the overhauler to check.  He found no problem but he reset the points for the SOS to near max gap.  2 years later working fine.  I  spent 2 weeks with my IA chasing the problem.  He and I had set the gap to the mid range.  I believe the gap being too tight was all the problem.  Wider gap, hotter spark.  Try that first.  Costs to me $500.  Costs to my IA who ate the parts and 60 hours labor were bad.   He found switches for less.

Eddie

[Conrad]

Thank you for reminding me that I should not be sad that the plane I ended up with has the original windshield in.

[DrBill]

My plane would not start right after an annual 2 years ago.  It would crank and crank and then when I let the key off, it would start.  Turned out to be the points setting on the start mag. They were not opening enough.  I had the mechanic pull the mag, and we set the points to like .030. Put back in and timed and voila, starts right up now.  He had sent the mags out for inspection and thought that the points would be set right when returned... Of  course they were not.

BILL

[bonal]

Davor8 I won't give you a like cause it saddens me to read your plight but I will say a very well written account and I'm certain you will find the problem. It is strange how we put so much trust in our very vintage aircraft if asked For a 500 plus mile road trip would you take your 1964 Olds Cutlass or your less than Ten year old whatever none would take the old car unless it was on a trailer for a car show. First thought is this thing safe to fly but always back in my mind is will it start and let me get home.

Keep us up to date because your research may save one of us in the future.

[DaV8or]

Davor8 I won't give you a like cause it saddens me to read your plight but I will say a very well written account and I'm certain you will find the problem. It is strange how we put so much trust in our very vintage aircraft if asked For a 500 plus mile road trip would you take your 1964 Olds Cutlass or your less than Ten year old whatever none would take the old car unless it was on a trailer for a car show. First thought is this thing safe to fly but always back in my mind is will it start and let me get home.

Keep us up to date because your research may save one of us in the future.

 

You know, that's the funny thing about this. I have a lot of experience with vintage cars and in my younger years used to drive cars from the '50s and '60s exclusively as my daily drivers. These were all not hot rods, but rather bone stock cars and I prided myself on that. As close to the factory as I could get them.

 

I eventually got fed up with lots of little issues all the time, so I chose a '64 Ford Falcon to be my daily driver and decided to rebuild everything that had anything to do with reliability and getting from point A to B. Custom rebuilt engine to my specs, rebuilt transmission with as many new parts as possible, drive shaft U joints and balance, completely rebuilt rear end with new bearing and seals, all new suspension bushings and joints front and rear, new shocks, all new brakes from the master cylinder on down even all the hardware, all new exhaust including new factory hangars, everything around the engine in the engine compartment was either new, or rebuilt including the steering box. Really the only thing I didn't redo was the original wiring harnesses and and the switch gear in the dash, but everything worked perfectly including the heater defroster that I did completely rebuild. It was a lot of work and with the exception of the engine, automatic transmission and rear end rebuilds, I did all the work myself including installs.

 

This was not a frame off show car, it was a very presentable daily driver. All original paint that still held a shine, decent chrome and bright work, good glass and an 80% original interior that was also still presentable. I did take this car on 500 mile trips. I drove it everyday and anywhere, but you know what? I could still never make it 100% reliable and trouble free like a modern new car. It still had issues time to time. The experience I had with that car had me come to the conclusion you just couldn't make a car from the '60s be as reliable as a car today (actually in the '90s when I came to this conclusion) for lots of reasons and here are a few-

1. Old tech. Even when new, it was not as good as what comes in cars today. Just the advantage of time.
2. Electrical wiring and switches, relays, solenoids, sockets, connectors and bulbs. You really have to commit to those too. All of it. Time and corrosion do as much damage as mileage and repetitive use.
3. The quality of rebuilt components and new aftermarket is just not as good as the factory new and most of the time factory new is just not a possibility on a vintage car. Even NOS parts suffer from aging on a shelf.

So in 1995 I sold the Falcon and bought a brand new car. That car served me for the next ten years flawlessly, got way better fuel mileage and I even got an airbag out of the deal! The take away is you can't beat brand new for reliability.

 

So when I signed up for a 1966 airplane, I did so with eyes wide open and a full understanding of what I was getting into. I knew it was going to be vintage cars all over again, but vintage is all I can afford to own. It is what it is. If I don't want these headaches, sell and stop flying. Those are my options. Can't afford new, previously owned, or even 20 years old. It is what it is.

[Mooneymite]

It's darn lucky an airplane is so much simpler than a Ford Falcon!

[DaV8or]

It's darn lucky an airplane is so much simpler than a Ford Falcon!

 

It is and it isn't. The car has more mechanical and hydraulic systems to service for sure, but it is a lot easier to work on. I specifically chose the Ford Falcon for the daily driver project because it is IMO, a wonderful piece of engineering and design with regards to serviceability. This is also true by extension to the first generation Mustang. The car was made and designed with ease of service in mind. Nearly everything is modular and created with a logical and effective way to get at all you need to get at. I was always impressed with that car in this regard. It was also a pretty darn good economy car for it's day.

 

Ok, somebody now go ahead and get it over with. That's because it's Fix Or Repair Daily.

 

The Mooney by contrast seems as though the factory really didn't give a damn about the guy that has to work on it. Their choice of fasteners, access to fasteners and locations for components continue to puzzle me. Some of it may be due to the "metalizing" of the original M20. The Mooneys nearly all of us fly really aren't clean sheet designs, but rather adaptations of adaptations. Numerous STCs and owner mods over the decades compound this as well.

[Mooneymite]

The Mooney by contrast seems as though the factory really didn't give a damn about the guy that has to work on it.

I agree!

Had Mooney simply made the inspection panels hinged instead of fastened with ump-teen screws, annuals would be quicker/cheaper!

Accessability to commonly replaced/inspected parts is usually painful and time consuming. While I understand the need for compactness in an efficient airframe, you'd think Mooney could have done better.

[DaV8or]

I agree!

Had Mooney simply made the inspection panels hinged instead of fastened with ump-teen screws, annuals would be quicker/cheaper!

Accessability to commonly replaced/inspected parts is usually painful and time consuming. While I understand the need for compactness in an efficient airframe, you'd think Mooney could have done better.

 

Yep. Just something as simple as bleeding the brakes is a nightmare.

[Vance Harral]

Dave, here's something to look into:

 

In our 1976 M20F, we discovered one day that the "always on" electric clock wasn't running. Investigation revealed that the power lead for the clock was shorted directly to ground.  What does this have to do with your ignition?  Well, we eventually traced our problem to a cannon plug just behind the firewall, which carried not only the power lead for the clock, but also all the connections for the ignition switch.  We found that the power lead for the clock was shorted to ground inside the cannon plug itself.  Your ignition wires might be similarly shorted to ground at that cannon plug.

 

Once we isolated our problem to the cannon plug, I got a pin extraction tool and a magnifying glass to debug.  I expected to find either a broken ground wire flopping around, or that the plastic body of the cannon plug had been compromised such that two pins were shorting together.  Here's where it gets weird: I found neither of these things to be true.  But after extracting the pins from the body of the plug, blowing everything out with compressed air, and reassembling it, the problem went away.  It hasn't returned since.

 

Our hypothesis is that the problem had to do with the braided ground shielding around some of the ignition wires.  At the cannon plug, the shielding jacket must be stripped from around the "signal" wire, and soldered to a separate pin of the cannon plug, so it can make a ground connection through the plug.  The braiding has very fine strands, a few of which can break loose without really compromising the ground connection.  But, then those loose ends are free to wiggle their way down into other sockets, to other pins, effectively shorting them to ground.  The braiding strands are so fine that it might be impossible to see them.  Now, I confess this hypothesis is a little weak, since an individual strand of the shielding is only about as big around as a fuse wire itself.  But I don't have any better explanation why simply cleaning out the cannon plug body would resolve a ground short.  We did inspect the hole for the clock power lead very carefully and found no breaks.  And every pin/solder/wire connection adjacent to it seemed to be in very good shape with nothing "interesting", except for the braided ground shield.

 

To be honest, the whole design makes me nervous now.  I can imagine a failure mode where a mag gets grounded in flight due to the grounded shield being compromised.  But, it doesn't seem to be a common problem, so I guess the risk is low.  The only thing I know for sure is that whatever the mechanism for short-to-ground, it was definitely occurring inside the cannon plug.

 

Anyway... suggest you trace the wires from your switch to the cannon plug they likely connect to.  Unscrew the cannon plug, and see if the short to ground goes away.  If it does, suggest you find a pin extraction tool and start debugging the cannon plug.  Seems like you've looked at everything else.

 

Hope that helps,

Vance

[DaV8or]

Dave, here's something to look into:

 

In our 1976 M20F, we discovered one day that the "always on" electric clock wasn't running. Investigation revealed that the power lead for the clock was shorted directly to ground.  What does this have to do with your ignition?  Well, we eventually traced our problem to a cannon plug just behind the firewall, which carried not only the power lead for the clock, but also all the connections for the ignition switch.  We found that the power lead for the clock was shorted to ground inside the cannon plug itself.  Your ignition wires might be similarly shorted to ground at that cannon plug.

 

Once we isolated our problem to the cannon plug, I got a pin extraction tool and a magnifying glass to debug.  I expected to find either a broken ground wire flopping around, or that the plastic body of the cannon plug had been compromised such that two pins were shorting together.  Here's where it gets weird: I found neither of these things to be true.  But after extracting the pins from the body of the plug, blowing everything out with compressed air, and reassembling it, the problem went away.  It hasn't returned since.

 

Our hypothesis is that the problem had to do with the braided ground shielding around some of the ignition wires.  At the cannon plug, the shielding jacket must be stripped from around the "signal" wire, and soldered to a separate pin of the cannon plug, so it can make a ground connection through the plug.  The braiding has very fine strands, a few of which can break loose without really compromising the ground connection.  But, then those loose ends are free to wiggle their way down into other sockets, to other pins, effectively shorting them to ground.  The braiding strands are so fine that it might be impossible to see them.  Now, I confess this hypothesis is a little weak, since an individual strand of the shielding is only about as big around as a fuse wire itself.  But I don't have any better explanation why simply cleaning out the cannon plug body would resolve a ground short.  We did inspect the hole for the clock power lead very carefully and found no breaks.  And every pin/solder/wire connection adjacent to it seemed to be in very good shape with nothing "interesting", except for the braided ground shield.

 

To be honest, the whole design makes me nervous now.  I can imagine a failure mode where a mag gets grounded in flight due to the grounded shield being compromised.  But, it doesn't seem to be a common problem, so I guess the risk is low.  The only thing I know for sure is that whatever the mechanism for short-to-ground, it was definitely occurring inside the cannon plug.

 

Anyway... suggest you trace the wires from your switch to the cannon plug they likely connect to.  Unscrew the cannon plug, and see if the short to ground goes away.  If it does, suggest you find a pin extraction tool and start debugging the cannon plug.  Seems like you've looked at everything else.

 

Hope that helps,

Vance

 

I will look for that. I'm not sure I have that connector though as I have not seen any in line connectors yet. What does the Cannon connector look like? I am not familiar with that type.

 

Edit: I Googled it and discovered that they are what I always called Amphenol connectors. Same thing, just different manufacturers I guess.

[Marauder]

OK, it's a long one. It's a story about why sometimes it costs so much to repair an airplane. It's not always the government's fault.

So I have been having trouble getting my engine started. So much so that I had stopped taking my airplane anywhere where I might shut the motor off. When it did start, I would just fly around the patch and then return home. Not entirely what I had in mind for a private airplane.

My fuel system has been rebuilt top to bottom on my watch. Completely IRANed fuel servo, rebuilt flow divider, new injector lines and now GAMI injectors with only about 40 hours on them. When I prime, I see a positive fuel flow. When she won't start, I get out and can smell fuel in the exhaust pipe. I'm pretty damn sure lack of fuel supply is not my starting trouble.

She gets a new Bracket air filter every annual and this one is now about 40 hours. My compressions are all good. She can breath and compact air with the best of them. This just leaves the spark.

Yes, I have Champion massive spark plugs. They have about 80 hours on them and have all been resistance checked. All good. I thought a good place to start might be my mags as they are Slicks and right at the 500 hour mark. According to the internet, Slicks are total POS and likely will need total replacement so why don't I just buy some Bendix mags, right? Well, we'll see about that.

So I pulled my mags and my harnesses and sent them up to Aircraft Magneto Service in Washington. Great people, got great recommendations and competitive prices. They did the inspection and sent them back. End report- nothing really wrong with them or the harnesses. I got off cheap and they hardly replaced anything. It turns out that Slicks can survive 500 hours of use after all.

Well this kind of sucked. I wanted them to find something wrong. I desperately wanted that "Aha! Here's the problem!" moment.

No such luck.

So I put the mags and harnesses back on but still searching for that "Aha!" moment. I pondered the ignition switch, the wiring and the starting vibrator. Speaking of which, I had no idea I had Shower of Sparks ignition system on my plane. Some mechanic somewhere installed it in my brain that I had an impulse coupling and I had never seen, nor heard a ignition vibrator on my plane, so never thought more of it. When I removed the mags, I discovered otherwise.

So where is this vibrator they speak of?? It turns out Mooney put them up high on the firewall, on the cabin side. Back in the day this wasn't such a bad place, but on any vintage plane with the 201 windshield conversion, this is the absolute worst place to put it! No wonder I never saw it! You need ESP and X-ray vision to find it.

How come I never heard it operate before? Well, it turns out I don't have a starting vibrator after all. Wait, didn't I just say I did have a Shower of Sparks, retard ignition system??! To my surprise I actually have a Slick Start solid state electronic booster that replaces the vibrator. It makes almost no noise when it operates.

Here's what the Slick Start looks like with my X-ray vision on-

I tested the Slick Start by disconnecting the starter motor, putting the prop at TDC on number 1, placing the bottom spark plug lead next to the cylinder head with a sizable gap, turning the master on and turning the key to start. Wow! ZAP!! That thing sure makes a big spark! So it makes a spark, but that's not to say that it still might not be defective somehow. More testing is needed later.

So with the Slick Start being almost impossible to access and the same being true for my ignition switch, I thought I would conduct a little continuity test with the wires I could get at, the P leads. A quick right P lead to ohm meter to ground connection verified that the right side of the ignition switch was working perfectly.

• Off grounded.
• Right, ungrounded.
• Left grounded.
• Both, ungrounded.
• Start grounded.

However the same check of the left P lead showed that the left mag, (you know, the one that starts the engine?!) to be grounded in all ignition positions!! That would certainly make it hard to start. Bear in mind I conducted these tests with the mags disconnected from the P leads, so there was no issue with the mags in the circuit.

So before I tackled the daunting task of gaining access to either the ignition switch, or the Slick Start, I decided to call the Slick tech support at Champion Aerospace just to see if there was any way that this grounded condition was normal for a Slick Start and maybe I was just doing the test wrong... or something.

No such luck. He said the Slick Start would not cause this situation. He also confirmed what I suspected, that the guy who installed the Slick Start didn't follow directions and installed it his own way. I have no F'in idea why!!! By doing so he made it really hard on himself and now me! The Slick Start is supposed to be mounted on the firewall on the engine side and connected directly to the mag and not have anything to do with the ignition switch. Because I wasn't sure exactly how it was wired, the tech support guy suggested I start with the ignition switch. He said that if not connected right, the Slick Start can fry the Bendix ignition switch eventually. Besides he added, "When was the last time that switch was changed?"

1975. According to the logs. Sleepy yet? No? read on...

OK, so the switch is coming out, but how? I thought if I just popped the headset jacks out below the switch and removed the switch bezel, it would squeeze out the little hole and down low enough to get at the wires. No such luck. The wires aren't anywhere near long enough to do that.

Then I thought that I could just unscrew the turn coordinator (actually an S-Tec 30) from the panel and push it back so I could get at those wires through the hole. Sorry Charlie!! That S-Tec bumps right up against the airframe tubing in this installation. The only thing left was to remove the metal panel from all the instruments then I could finally get at this little bitc... I mean switch.

Front seats out, pilot's side wall panel off, whole radio stack on the back seat, a zillion screws and a couple of custom wrenches to get at the idiot nuts on the backside of the panel later, (a whole other rant! ) the panel was lose and instruments flopping about freely. Now I should be able to get that S-Tec out altogether. After disconnecting the multi pin connector on the back of it I thought I was home free.

Denied!!

As I tried to ease it out of the rat's nest, I then discovered two itzy bitzy wires that have no plug that run the little light inside. The other end of those wires disappear into a wiring bundle as big my arm with about 2,000 zip ties holding it tightly together. At this point I would start banging my head on something, but I had already done that enough working under there!

Finally, I got a break. It occurred to me that I could now push the S-Tec backwards with the connector off and everything lose and sloppy and then flip the switch up and over another wiring bundle and have it hang down where I could access it. It worked!!

The sky cleared, trumpets sounded and there it was!

After fully documenting where all the wires are attached with photos, labels and a drawing, I finally had the 40 year old switch out on the bench. It tested... perfect. No problems. AGGGGGGHHHHH!!!! Why o' why could it not have been a melted, crumbling mess of plastic and tin??!!

I can tell you all are starting to nod off, so my work here is almost complete, so I'll make it shorter. Initial tests of the P leads show there are no shorts to ground. I had to go home and the other wires have not been investigated yet. It now turns into a game of- "Well, since we're in there..."

I am considering installing a new ignition switch anyhow (about $410! Ouch!) , new P leads, a new landing gear switch as it is original and now pushing 50 and relocating the Slick Start to the correct placement and wiring as per instructions. I think I'm also going to go to the Tempest UREM37BY plugs too.

So, out of pocket expenses haven't been too bad so far. Only about $700 for the mag inspection, but if I were charging for the labor... well it would be climbing. These airplanes are not designed to be worked on. At all. Period. For those still reading I have to say...

To be continued...

Dave - I'm convinced there is a special class of electrical demon that is not only unique to airplanes but an more evil one specific to Mooneys. It is bad enough to contend with finger scrapping access, but to chase the demon through inaccessible locations is, well, just not right. I have dealt with the demon on several occasions and finally resorted to bringing in a priest to perform an exorcism to once and for all get rid of the bast$&d.

Sent from my iPad using Tapatalk

[Guitarmaster]

Dave - I'm convinced there is a special class of electrical demon that is not only unique to airplanes but an more evil one specific to Mooneys. It is bad enough to contend with finger scrapping access, but to chase the demon through inaccessible locations is, well, just not right. I have dealt with the demon on several occasions and finally resorted to bringing in a priest to perform an exorcism to once and for all get rid of the bast$&d.

Sent from my iPad using Tapatalk

Be careful with the exorcism. If done improperly, the demon will run somewhere else! Then, as Chris said, you may have to offer a financial sacrifice to rid yourself of it.

Seriously, best of luck and please keep us posted!

Sent from my iPad using Tapatalk

[MyNameIsNobody]

What a great thread. Really good (and maybe cathartic) Write-up Dave. I am just waiting for a starting issue to "pop up"...I wish I had your patience. It reminded me of a recent Fast & Loud episode I watched. It was a Falcon I believe, but might have been a Mustang...Mechanic had a bolt break off. He weled a nut on not once, twice, three times...No, four hours later and the fourth welded nut he was able to extract the broken rusted screw from the engine. I marveled at his patience and perceverance. You have raised the bar in that department. God bless your thorough patience and logical trouble-shooting mind. Better than a mystery thriller I look forward to the hero solving the case and getting the girl...back in the air. Good luck and Tally Ho!

[AndyFromCB]

Sounds like my voltage regulator saga from early when I bought the plane and almost lost it. Keeping the Bravo going over last 4 years has humbled me considerably and really toughened my knuckles and forehead. I have found new ways of twisting under the panel. Trust me, it ain't easy for this chubby guy.

 

Congrats on finding the problem. Back upstairs to fit more base trim in a house that has not one straight angle in it. 

[N601RX]

My 67 didn't use a cannon plug to exit the firewall or anywhere in the wiring harness. They just use a block of rubber with a stamped piece of metal around it. What I did find is that someone had spliced the pleads and wires to the sos in a couple of places with poorly crimped butt splices. I have the 201 window also and the best way I have found to access the area the sos is mounted in is to remove the radio trays and back plates for the top couple of radios. You can loosen the screws or remove them and the backplate will seperate from the tray. Then remove the tray and you will have good access to that area. Before we put the 201 window in my plane we mounted every thing possible with nutplates and rivet nuts so it all could be removed without having to hold the nut on the backside. Did the same thing to the radio stack and panel also.

[DaV8or]

Dave - I'm convinced there is a special class of electrical demon that is not only unique to airplanes but an more evil one specific to Mooneys. It is bad enough to contend with finger scrapping access, but to chase the demon through inaccessible locations is, well, just not right. I have dealt with the demon on several occasions and finally resorted to bringing in a priest to perform an exorcism to once and for all get rid of the bast$&d.

Sent from my iPad using Tapatalk

 

This job has had me "losing my religion" for a while now, but I think it's going to make me find religion for sure!! It might be worth joining the Catholic church just to get that exorcism done!

[DaV8or]

Back upstairs to fit more base trim in a house that has not one straight angle in it. 

 

Oh I have been there my friend! MDF molding, a really good compound miter saw and this little friend will save you!!

 

[DaV8or]

My 67 didn't use a cannon plug to exit the firewall or anywhere in the wiring harness. They just use a block of rubber with a stamped piece of metal around it. What I did find is that someone had spliced the pleads and wires to the sos in a couple of places with poorly crimped butt splices. I have the 201 window also and the best way I have found to access the area the sos is mounted in is to remove the radio trays and back plates for the top couple of radios. You can loosen the screws or remove them and the backplate will seperate from the tray. Then remove the tray and you will have good access to that area. Before we put the 201 window in my plane we mounted every thing possible with nutplates and rivet nuts so it all could be removed without having to hold the nut on the backside. Did the same thing to the radio stack and panel also.

 

Yes! I came to this conclusion today also! I realized I can get decent access to the wire bundle if I do exactly as you suggest and take the back plate off my audio panel tray, then remove that tray. The tray below is for my Garmin 430 and it's opening is plenty big enough for my hand and it has a big hole in the top of the tray, so I don't think I have to remove it. I only just discovered that the back of the Garmin trays are easily removable by observation today. Earlier I thought I would have to monkey with the multi pin connectors. Thank you Garmin!

 

I have also schemed on solutions to putting the panel back on that includes more use of rivet nuts and custom nut plates that I will fabricate. Seriously, having to hold a nut on the back side with a wrench is bull crap!

[DaV8or]

So, today's "progress"- 

 

I checked all the wires and of course... all looks well. I reconnected everything to the switch as it was and preformed the exact test from the exact connection points as I did before dis-assembly and... it works perfectly. No "Aha" moment.

 

I decided to make the commitment to relocating the Slick Start in the correct location and removed it and two of the four wires to it. I also came up with a strategy for replacing the P leads. To my disgust, I discovered that my plane has been using the wrong Slick Start for years now. I have the one that is intended for Bendix mags and of course I have Slicks.

 

I get how it happened though. Back in 2004, a previous owner replaced the vibrator with the Slick Start and at that time the engine had Bendix mags. In 2006, the engine was rebuilt and the owner then spec'd new Slick mags for the rebuild. Because the Slick Start was put in the wrong place, nobody could see it and likely didn't even think about it. It has been working since 2006, so tomorrow I will be calling the Slick tech support guy again to find out what this means for me and how bad is it to run your mags with the wrong one.

 

I think I know what he'll say... ... ...

[N601RX]

The original SOS was the same for both Slick and Bendix.  However if you look in the overhaul manual for it it shows how to set the correct coil current for the slick or bendix mag.   The setting is different, with the bendix being higher.  My guess is that with the slick start there isn't an adjustment and you just have to purchase the correct part number for either slick or bendix.

[DaV8or]

The original SOS was the same for both Slick and Bendix.  However if you look in the overhaul manual for it it shows how to set the correct coil current for the slick or bendix mag.   The setting is different, with the bendix being higher.  My guess is that with the slick start there isn't an adjustment and you just have to purchase the correct part number for either slick or bendix.

 

Your guess is the same as my guess. Today I'll call tech support before shelling out $800 for another Slick Start though just in case.

 

Might as well start now- Anybody want to buy a used Slick Start for Bendix mags??

[AndyFromCB]

Oh I have been there my friend! MDF molding, a really good compound miter saw and this little friend will save you!!

 

 

I've got one of them. On this portion of the house, though, I am matching some existing trim so instead of using miter saw, I am coping with a handsaw and carving tools. Takes about an hour per corner. Mrs keeps on telling me perfection is enemy of good enough, but I can't stop myself.

[DaV8or]

So, I got some good news today. The Slick tech support guy said there is no serious problem with running the Slick Start intended for Bendix mags on Slick mags. The other way around is bad. Bendix mags with the Slick Start intended for Slick mags will damage the Bendix mags.

 

The back story is, when they developed the Slick Start  as a solid state, modern replacement for the Bendix mechanical vibrator, they tried to make a drop in replacement compatible with either mag, but better. The Slick Start makes a bigger spark for a longer duration than the old vibrator ever could. This means higher voltage.

 

They made just one unit originally, but soon there were problems with the Bendix mags. Turns out the higher voltage was causing the Bendix mags to become demagnetized. So they developed two versions with the Bendix version being a lower voltage. So using the Slicks with the Bendix version of Slick Start is no big deal. Only downsides are I get less of a spark as I might have had and the Feds frown on it because all the paperwork doesn't line up.

 

I guess that's why it has worked fine for the last 500 hours with no damage to the mags.