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melted 2 gage starter wire

drmax

Well Known Member
Has anyone experience this? I'm certain the starter solenoid is toast. Also to ck the starter, I went direct with external batter to the starter, and no spin, so this most likely is shot. (skytech) There was some belief that if the starter stuck engaged, it would turn into a DC motor, generating the amps to burn the wire like it did. After talking with skytech, I've realized this is hogwash, as well it sticking, which also learned that to be highly unlikely and if it did, at the engine spin or RMPS, the starter has a clutch and that gear would only free wheel. So, I didn't know the battery could smoke that thick of wire. I lastly could believe that the key switch stuck to the "start" possition. If this is the case, i could find that to be the issue right now with a meter. I'm not about to throw $165 at a new switch without verification. (btw, I will be keeping this type of starting method)
I'll pull the starter tomorrow and most likely sending off for remanned unit, it it is dead, which I'm pretty sure it is. I did find that a diode had not been installed on the master solenoid, which may have helped to weld the start circuit together in the switch...if it is indeed the issue. Lastly, the flywheel gear looks brand new. Thx for listening. DM
 
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Ouch ...

Sorry to hear that. As I recall Bob Nuckoll's discussion of batteries and shorts, a dead short across the main battery terminals can produce 100s of amps of current. All that power and no resistance to flow. I'm not enough of a Lyco starter expert to know why yours would have a failed in that spectacular way. Personally opinion: I doubt it was the lack of the diode.
 
If wired like most RV's (and most aircraft for that matter) the starter is about the only component not protected by a fuse or circuit breaker. If you had a dead short to ground in your starter you would likely end up with a burned starter wire (even 2 gauge), perhaps a welded master and/or starter solenoid, perhaps a damaged engine ground wire, and perhaps a damaged battery. I would check all before further operation.
 
Actually, the missing diode is on the master solenoid and ordered that up. Really puzzled why the heck this happened...where it happeded on the cable. There could have been no short to ground. Uncertain how to check the starter. Guess I'll wait for the new starter solenoid and make a new 2 gage able and try again.
 
If wired like most RV's (and most aircraft for that matter) the starter is about the only component not protected by a fuse or circuit breaker. If you had a dead short to ground in your starter you would likely end up with a burned starter wire (even 2 gauge), perhaps a welded master and/or starter solenoid, perhaps a damaged engine ground wire, and perhaps a damaged battery. I would check all before further operation.
There is a small wire going from the starter solenoid to one of the post on the starter solenoid. I "guessing" this is what sends the small current to throw the small gear out of starter, into the flywheel? This will need replaceing as it caught some heat. How to check the starters intergrity with a meter, if possible? I was thinking there should be some ohms showing on the main starter cable stud, to case gound...and that is indicating "open". At least if I knew this was shot, I could get it sent off for a reman.
 
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ohm ck

I just had access to a vehicle starter. The ohm reading from the windings stud to ground is .300. Mine was OL. Gotta be toast. Will yank it and test it propperly and let ya's know.
 
There is a small wire going from the starter solenoid to one of the post on the starter solenoid. I "guessing" this is what sends the small current to throw the small gear out of starter, into the flywheel? This will need replaceing as it caught some heat. How to check the starters intergrity with a meter, if possible? I was thinking there should be some ohms showing on the main starter cable stud, to case gound...and that is indicating "open". At least if I knew this was shot, I could get it sent off for a reman.

Don't worry about the diode. If missing, you would most likely ether have the switch quit working or have a stuck starter (starter remains engaged after release of the start switch). This would not likely cause your problem, but it would likely destroy either your starter, starter gear, starter gear shear pin, or flywheel gear.

It would help if you posted a schematic diagram of your starter system, but I assume, since you have just a small wire going from the starter solenoid to the starter (along with the large 2 gauge wire, of course), that your starter has an internal solenoid that engages the gear and energizes the starter motor.

If so, when you start the engine, your start switch energizes the starter solenoid which applies power to the starter's internal solenoid, which then engages the starter gear and energizes the actual starter motor. So your external starter solenoid is likely only used to energize the internal starter solenoid. Many RV starter installations have the main starter wire and internal starter solenoid wire jumpered togerther at the starter, so the external start solenoid engages both through the large wire.

To test the actual starter motor, you need to apply power to both the starter's solenoid (small wire) and starter motor coil input (large wire) at the same time. To test just the starter motor coil (which I suspect is shorted out), apply power to just the intenal starter solenoid (small wire). The starter gear should extend and you should hear a "click" of the internal solenoid. Then with the solenoid engaged check the resistance of the main starter cable stud to ground. There should be at least more than a couple of ohms. It may be difficult to tell because the starter coil is very low resistance to begin with. You could use an external battery to apply power to both the small terminal and large terminal at the same time, but be prepared to disconnect quickly if the starter doesn't turn!

Edit: Also, more likely, and I assume you did, but did you check that the 2 gauge starter wire is not just chafing to ground somewhere? Regardless, be sure to check your engine ground strap/wire. If it is also charred/damaged, then check alternate ground paths (fuel lines, control cables, etc.). I would be very concerned about other damage this could have caused. It takes a lot of current to burn a 2 gauge wire, and you must assume the ground side could also have sustained damage.
 
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Don't worry about the diode. If missing, you would most likely have had a stuck starter (starter remains engaged after release of the start switch). This would not likely cause your problem, but it would likely destroy either your starter, starter gear, starter gear shear pin, or flywheel gear.

It would help if you posted a schematic diagram of your starter system, but I assume, since you have just a small wire going from the starter solenoid to the starter (along with the large 2 gauge wire, of course), that your starter has an internal solenoid that engages the gear and energizes the starter motor.

If so, when you start the engine, your start switch energizes the starter solenoid which applies power to the starter's internal solenoid, which then engages the starter gear and energizes the actual starter motor. So your external starter solenoid is likely only used to energize the internal starter solenoid. Many RV starter installations have the main starter wire and internal srarter solenoid wire jumpered togerther at the starter, so the external start solenoid engages both through the large wire.

To test the actual starter motor, you need to apply power to both the starter's solenoid (small wire) and starter motor coil input (large wire) at the same time. To test just the starter motor coil (which I suspect is shorted out), apply power to just the intenal starter solenoid (small wire - the starter gear should extend and you should hear a "click" of the internal solenoid) and then check the resistance of the main starter cable stud to ground. There should be at least more than a couple of ohms. It may be difficult to tell because the starter coil is very low resistance to begin with. You could use an external battery to apply power to both the small terminal and large terminal at the same time, but be prepared to disconnect quickly if the starter doesn't turn!
Removed info. Not relevant
 
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OK. My comments still apply. It's most likely either the 2 gauge wire chafing or your starter is bad.
 
OK. My comments still apply. It's most likely either the 2 gauge wire chafing or your starter is bad.
Ok. Gotta be starter as the wire could not have chafed to anything. It's out in the air. I'll pull this thing off in the next couple days and test it better.
After this, I'll install and led lt on the panel, showing when that cable is engergized....:) (I was seconds from taking off when the infamous smell crawled up my nose...and not other abnormalities. I bet if I had been looking I would have seen quite a drop on the ammeter. Thx, DM
 
After this, I'll install and led lt on the panel, showing when that cable is engergized....:) (I was seconds from taking off when the infamous smell crawled up my nose...and not other abnormalities. I bet if I had been looking I would have seen quite a drop on the ammeter. Thx, DM

Glad I installed my "Starter On" LED. You will want to install a 1A fuse on this wire.

A shorted battery to ground through starter windings can consume much more than 100 Amps. 100 Amps would warm the wire not melt it. A dead short to ground on an Odyssey PC680 can consume over 1800 Amps. Your alternator was also supplying additional current.

A good reason for having an EFIS/EIS with current/voltage sensing and setting limits to warn you. I have three hall effect sensors...main bat, aux bat and alternator.
 
Following the damage

If the #2 is melted along its whole length then something fell against the terminal on the starter or the starter is shorted. If it was a chafed wire the damage would have stopped somewhere along the wire and would have put a nice arc weld somewhere.
 
Loose Connection

If the wire is melted near either end, the problem is could be a loose connection. Loose connections develop high resistance and will overheat.

Gary Slatt
RV-7A Flying 260Hrs
 
Glad I installed my "Starter On" LED. You will want to install a 1A fuse on this wire.

A shorted battery to ground through starter windings can consume much more than 100 Amps. 100 Amps would warm the wire not melt it. A dead short to ground on an Odyssey PC680 can consume over 1800 Amps. Your alternator was also supplying additional current.

A good reason for having an EFIS/EIS with current/voltage sensing and setting limits to warn you. I have three hall effect sensors...main bat, aux bat and alternator.
"melted" the insullation, not the wire. Sorry if this has confused some. Pulling starter now and bench checking it my way, then off to TX it goes for a replacement/remann. Is your LED light pwr attached from the downstream side of your starter solenoid? Attached is a pic of the reg. Please point out which post, if so that you connected. I won't be starting my plane again, until this is installed. http://www.vansaircraft.com/cgi-bin...02-338-576&browse=electrical&product=start-sw
 
If the wire is melted near either end, the problem is could be a loose connection. Loose connections develop high resistance and will overheat.

Gary Slatt
RV-7A Flying 260Hrs
2" from end near regulator. Insullation on wire not effected at the end. Crimp is good. Possibly a piece of crappy 2 gage wire found a path of least resis. Dunno. It's all coming off in a couple of hours.
 
"melted" the insullation, not the wire. Sorry if this has confused some. Pulling starter now and bench checking it my way, then off to TX it goes for a replacement/remann. Is your LED light pwr attached from the downstream side of your starter solenoid? Attached is a pic of the reg. Please point out which post, if so that you connected. I won't be starting my plane again, until this is installed. http://www.vansaircraft.com/cgi-bin...02-338-576&browse=electrical&product=start-sw

My LED power comes from the "I" terminal of Van's start solenoid using a 1 Amp in-line fuse and 18 ga wire(just for durability in the engine area). See post #11.

Did you use welding wire or mil spec 2ga? Tefzel has a melting point around 500*F.
 
My LED power comes from the "I" terminal of Van's start solenoid using a 1 Amp in-line fuse and 18 ga wire(just for durability in the engine area). See post #11.

Did you use welding wire or mil spec 2ga? Tefzel has a melting point around 500*F.
I am not the builder. The wire states M22759 on it, am I'm sure it is the recommended wire. With the wire out, I'm concerned how the wire B11-16 per diagram was ran on the 2 gage wire. I examined under a scope and did not find a weld spot, for I feel it that were the case, it would have vaporized this 16 gage wire. I may run that seperate, on the rebuild. The only thing those 2 wires now have in common, are melted insullation.
Again, going off this diagram...http://www.skytecair.com/images/Diag/Van's Starter Wiring Lg.jpg
Starter is off and going in via fedex tonight.
 
If the 16 gage B11 wire and the 2 gage P17 wire both have melted/burned insulation it could be because the solenoid at the starter welded shut.

The wires both assume intermittent loads, so a continuous current with a stuck solenoid could do overheating damage without melting the wires.
 
If the 16 gage B11 wire and the 2 gage P17 wire both have melted/burned insulation it could be because the solenoid at the starter welded shut.

The wires both assume intermittent loads, so a continuous current with a stuck solenoid could do overheating damage without melting the wires.
If the stuff melted 1st, then wire touched, I agree. But the wires should never have gotten that hot in the 1st place....unless there was a worn spot in plastic and then the process started. I didn't see an open flame...but the stuff if black and I would say there was. Dunno and this is giving me a headache. Starter on the way back, wiring will be replaced and rerouted and an LED light installed. I'm dun
 
If your Van's firewall mounted start solenoid remained closed after the start switch was released...either due to a bad start switch or stuck solenoid contacts, the 16 Ga wire pulling 25-35 Amps would overheat and melt into the 2 ga. You already checked key switch, that leaves the solenoid. What was your continuity across FW mtd start solenoid large studs while unenergized? It should be open.

It sounds like you are replacing the correct components. Then a peek at that LED after startup will ensure the smoke stays inside the wires. Thanks for sharing. Let us know what you find out about your starter too.
 
If your Van's firewall mounted start solenoid remained closed after the start switch was released...either due to a bad start switch or stuck solenoid contacts, the 16 Ga wire pulling 25-35 Amps would overheat and melt into the 2 ga. You already checked key switch, that leaves the solenoid. What was your continuity across FW mtd start solenoid large studs while unenergized? It should be open.

It sounds like you are replacing the correct components. Then a peek at that LED after startup will ensure the smoke stays inside the wires. Thanks for sharing. Let us know what you find out about your starter too.
I have not ck'd the key switch yet...but I will. Not even the start sol., but was black and will be replaced regardless. Will ck that too. Across large lugs of the PM style starter, was OL. Still being sent in, for i would imagine it's toast. I am holding the 16 gage wire off the 2 gage (this go) with standoffs. (before the wire were run tight together...not a good idea) I suggest yall do the same. Clamps are cheap, as well as the LED lamp. I'll report back.
 
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For those of us who wonder what the "I" terminal is connected to...

http://www.colehersee.com/assets/files/drawings/1335978582-dwg24021.gif
So then is terminal "s" a ground to frame? If so, thats a handy place to grab the ground. While I'm writing, when I get the diodes from vans for my master and start Sol., will there be directions of which studs, and which directions to use them? If not, I suppose I'll find this back through the builder notes. Thx gents for being around. I like this neighbor hood...:)
 
wire smoke?

I believe the concept of the #16 second wire to the starter was to not have to install a starter relay on the firewall but to seperatley switch 12v directly to the "S" terminal to engage the built in starter solenoid elemination the need for a seperate started relay.

http://www.skytecair.com/images/P1/Exp%20LS%20Wiring_1100.jpg

I see several potential flaws in this but these two stick in my mind:

1, A constantly hot #2 conductor out to the starter with no overcurrent protection. With a fire wall relay the only constantly hot portion is the buss between the the master relay and the starter relay. Still no overcurrent protection but a far less exposed circuit segment. With a firewall mounted starter relay configuration if somthing shorts the #2 conductor to ground it will be hot when the relay is engaged. Without the relay a shotred #2 will conduct max current until it smokes the cable.

2, A long #16 conductor thatmay not be overcurent protected that would not be there if a starter relay was installed as recommended by SkyTek.

I put a 5 amp CB in the circuit feed the power to the starter relay that would open before the points of the relay would weld shut. If the on board starter solenoid fails closed, you will draw a lot of current and the only way to know is with a starter LED or keeping a close eye on the amp meter to make sure the load stays in the normal range. It is relatively rare for a solenoid to fail closed but ids possible. If the starter shorts to ground on the B+ side you will let the smoke out of the #2 cable pretty fast and there is very little you can do to protect from this as the starter pulls 200 +- amps making it unrealistic to over current protect that circuit.

I believe that a PC680 shorted to ground can generate close to 2K amps and have a burned wedding band and a blister scarred finger from just a glancing touch of the firewall while holding a non insulated tool on the positive battery pole. Feel free to correct me if my asumption here are incorrect.
 
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So then is terminal "s" a ground to frame? If so, thats a handy place to grab the ground. While I'm writing, when I get the diodes from vans for my master and start Sol., will there be directions of which studs, and which directions to use them? If not, I suppose I'll find this back through the builder notes. Thx gents for being around. I like this neighbor hood...:)

Power from start switch attaches at "S" terminal. The diode red banded end with small ring terminal also attaches here. The larger end under the mount bolt/washer.

http://www.aircraftspruce.com/catalog/elpages/solenoidassy.php
 
Melted Insulation

2" from end near regulator. Insullation on wire not effected at the end. Crimp is good. Possibly a piece of crappy 2 gage wire found a path of least resis. Dunno. It's all coming off in a couple of hours.

I'm trying to understand the statement above. Are you saying that the insulation is melted in a localized spot 2" from the end of the cable? Is it possible that this was melted from exhaust heat and not a short?

Skylor
 
I'm trying to understand the statement above. Are you saying that the insulation is melted in a localized spot 2" from the end of the cable? Is it possible that this was melted from exhaust heat and not a short?

Skylor
Started 2" from the end of the wire, near solenoid approx 5" long. Not from exhaust.
 
I believe the concept of the #16 second wire to the starter was to not have to install a starter relay on the firewall but to seperatley switch 12v directly to the "S" terminal to engage the built in starter solenoid elemination the need for a seperate started relay.

http://www.skytecair.com/images/P1/Exp%20LS%20Wiring_1100.jpg

I see several potential flaws in this but these two stick in my mind:

1, A constantly hot #2 conductor out to the starter with no overcurrent protection. With a fire wall relay the only constantly hot portion is the buss between the the master relay and the starter relay. Still no overcurrent protection but a far less exposed circuit segment. With a firewall mounted starter relay configuration if somthing shorts the #2 conductor to ground it will be hot when the relay is engaged. Without the relay a shotred #2 will conduct max current until it smokes the cable.

2, A long #16 conductor thatmay not be overcurent protected that would not be there if a starter relay was installed as recommended by SkyTek.

I put a 5 amp CB in the circuit feed the power to the starter relay that would open before the points of the relay would weld shut. If the on board starter solenoid fails closed, you will draw a lot of current and the only way to know is with a starter LED or keeping a close eye on the amp meter to make sure the load stays in the normal range. It is relatively rare for a solenoid to fail closed but ids possible. If the starter shorts to ground on the B+ side you will let the smoke out of the #2 cable pretty fast and there is very little you can do to protect from this as the starter pulls 200 +- amps making it unrealistic to over current protect that circuit.

I believe that a PC680 shorted to ground can generate close to 2K amps and have a burned wedding band and a blister scarred finger from just a glancing touch of the firewall while holding a non insulated tool on the positive battery pole. Feel free to correct me if my asumption here are incorrect.
Should be a runaway type circuit device to prevent this type of issue...automatically...thermal switch or what have you. Really, if you don't have time to reach down and turn off the master, seems pretty scary. Just ask me.
 
starter tested fine....however overhauling (8 yrs of use) I'm stumped.
don't know what happened. Will start reassembly as soon as I get the starter back. Installing LED this weekend. Won't turn the key without it.
 
starter tested fine....however overhauling (8 yrs of use) I'm stumped.
don't know what happened. Will start reassembly as soon as I get the starter back. Installing LED this weekend. Won't turn the key without it.

Take a look at the wire strands of the 2 gauge start cable where you see signs of heat damage. Perhaps you will find broken strands due to cable flexing or corrosion. This could reduce the effective cable size and cause localized overheating of the cable during normal starting.
 
Take a look at the wire strands of the 2 gauge start cable where you see signs of heat damage. Perhaps you will find broken strands due to cable flexing or corrosion. This could reduce the effective cable size and cause localized overheating of the cable during normal starting.
I will look closer at this. Thx guys for listening.
 
understanding the solenoids

Hello. Troubleshooting some more and not understanding what I'm reading with meter. On the master solenoid, I was assuming that the little terminal would have no voltage until the master switch was turned on, then voltage would be applied, pulling the contacts and then running power to the start solenoid, and ready for the key to be turned. As it sits, there is 12.5 volts on the little terminal with master off. Oddly enough, when I do turn on the master switch, the master clicks. So, why is there power sitting at this small stud, with master off? This is twisting my mind. DM
 
Hello. Troubleshooting some more and not understanding what I'm reading with meter. On the master solenoid, I was assuming that the little terminal would have no voltage until the master switch was turned on, then voltage would be applied, pulling the contacts and then running power to the start solenoid, and ready for the key to be turned. As it sits, there is 12.5 volts on the little terminal with master off. Oddly enough, when I do turn on the master switch, the master clicks. So, why is there power sitting at this small stud, with master off? This is twisting my mind. DM

Your master switch provides the path to ground. If you measure the other little terminal to ground, you will get 12.5 too.
 
Your master switch provides the path to ground. If you measure the other little terminal to ground, you will get 12.5 too.
Hello Wayne. Only one little term on the master. (we are talking about the master sol. now) So it normally carries 12 volts on stud, then you ground it with master switch on. Ok, think we're getting somewhere....When the key is turned to start, does it carry 12 volts through the key, or is it suppose to be providing a path to ground? If voltage, it is only allowing .400 (according to meter). I get "no" reading on "I" terminal on new start solenoid when turing the key. Also no audible click. Will ck back here later. Thx, DM
 
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Hello Wayne. Only one little term on the master. So it normally carries 12 volts on stud, then you ground it with master switch on.

Ok, think we're getting somewhere....When the key is turned to start, does it carry 12 volts through the key? If so, then it is only allowing .400 (according to meter)...or is this also suppose to be providing a path to ground? I get "no" reading on "I" terminal on new start solenoid. Also no audible click. Will ck back here later. Thx, DM

The master solenoid I have has two terminals. They are also made with one small terminal like yours. One end of your coil winding is hot from the battery pos + feeding one of the big terminal studs. So a source to grd must be provided through small stud.

On Van's start solenoid you test like this...connect pos to either big stud, connect negative to steele mount feet, then when you connect pos to the small "S" term stud you will hear it close. Now check "I" term to neg mount foot and you will read battery voltage.

When you turn on your master powering up main bus, positive voltage is sent to start switch. When you turn key to start position, positive is sent to "S" term of Van's start solenoid which energizes the coil winding through the foot mount to ground.
 
Hello Wayne. Only one little term on the master. (we are talking about the master sol. now) So it normally carries 12 volts on stud, then you ground it with master switch on. Ok, think we're getting somewhere....When the key is turned to start, does it carry 12 volts through the key, or is it suppose to be providing a path to ground? If voltage, it is only allowing .400 (according to meter). I get "no" reading on "I" terminal on new start solenoid when turing the key. Also no audible click. Will ck back here later. Thx, DM

That is correct on the I terminal.

The internal circuitry of the START solenoid is given in the link on my post #22 of this thread.

The MASTER solenoid is quite different.
 
Is 12 volts sent through the switch? If so, it is not working.

I hooked it all up, and there is no click to the starter solenoid.
(of course, the starter is still not installed)

Should it click or not?
I'm trying to determine if I need a new rotary switch.
 
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I have not ck'd the key switch yet...but I will. Not even the start sol., but was black and will be replaced regardless. Will ck that too. Across large lugs of the PM style starter, was OL. Still being sent in, for i would imagine it's toast. I am holding the 16 gage wire off the 2 gage (this go) with standoffs. (before the wire were run tight together...not a good idea) I suggest yall do the same. Clamps are cheap, as well as the LED lamp. I'll report back.

Way back in post 26 & 27...start switch checked???

You should have a fuse or breaker in between main bus and start switch, so check that first. Then after that 12V+ should pass through start switch to start solenoid "S" terminal when key is turned to start position. Start solenoid mount foot must be making continuity to airframe ground.

It would help to have two people and preferably one with some troubeshooting skills. Too bad you are not closer.
 
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Way back in post 26 & 27...start switch checked???

You should have a fuse or breaker in between main bus and start switch, so check that first. Then after that 12V+ should pass through start switch to start solenoid "S" terminal when key is turned to start position. Start solenoid mount foot must be making continuity to airframe ground.

It would help to have two people and preferably one with some troubeshooting skills. Too bad you are not closer.
In between being sick, tending to a couple youngins and bitter cold, I didn't ck the switch yet. I'd only, a couple days ago got back on it. I didn't see a fuse in the wiring diagram or c/b. This would explain why there is not a c/b, unlike my neighbors print for is 6. Hopefully that is it. I'll have a look under the dash in the morning. I did get my red LED installed today.:)
 
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found 12 volts

I missed it completey on the w/d, that this switch gets power through the 10 amp breaker, which also supplies to the eng gages. The breaker was not labeled as such...and yes, they had all still been out since the incident.

So Wayne, seems like since I have all the troubleshooting skills, I should have you come over....:D
 
All worked like a champ. I'd suggest to anyone to install the "energized ciruit" l.e.d. in the panel, as well as having the 16 wire stand off from the 2 gage wire. What happened to me, could happen to anyone.
Thx for the advice and listening...dm
 
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