A Question for DigiPanel Experts

[SteveW]

Greetings and THANKS in advance for all of the information shared here...

I've recently come upon an old DigiPanel. I hooked it up and it works - well - Battery and Oil Pressure at least. I haven't run the sensor down to
the transmission pan yet, and the sensor for the thermostat housing was cut off. I got a replacement from JimK but haven't spliced it in yet.

But it got me to wondering... what's so magic about the sensors ?? Two wires terminating at a small piece of copper to be secured under a bolt head.
Is is some sort of bi-metal ?? Is it just a regular old Type K thermocouple ?? Anybody know ??

Steve W
1973 23'
Southern California

 

[robert mueller]

Steve,

IIRC it's a thermister:

https://en.wikipedia.org/wiki/Thermistor

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Steve
Weinstock
Sent: Tuesday, May 23, 2017 2:19 PM
To: gmclist
Subject: [GMCnet] A Question for DigiPanel Experts

Greetings and THANKS in advance for all of the information shared here...

I've recently come upon an old DigiPanel. I hooked it up and it works -
well - Battery and Oil Pressure at least. I haven't run the sensor down to
the transmission pan yet, and the sensor for the thermostat housing was cut
off. I got a replacement from JimK but haven't spliced it in yet.

But it got me to wondering... what's so magic about the sensors ?? Two
wires terminating at a small piece of copper to be secured under a bolt
head.
Is is some sort of bi-metal ?? Is it just a regular old Type K thermocouple
?? Anybody know ??

Steve W
1973 23'
Southern California



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[SteveW]

Thanks Rob -

That does make sense...

The part from JimK is the copper piece that goes under a bolt head and about 6 inches of lead wire (red / black).

I'll call Applied tomorrow to ask - but I'll inquire here as well:

How do I attach this new sensor? Crimp it to the existing (cut) wires? Twist and solder it under some heat shrink? Ugh.

Steve W
1973 23'
Southern California

 

[robert mueller]

Steve,

IIRC again!

The wire is a very small gauge and when I replaced on e that was damaged I
twisted, soldered and shrink tubed the connection. BTW Harbor Freight sells
short sections of marine shrink tube that ooze "stuff" when shrunk. I assume
this seals the connection and prevents corrosion.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Steve
Weinstock
Sent: Tuesday, May 23, 2017 3:31 PM
To: gmclist
Subject: Re: [GMCnet] A Question for DigiPanel Experts

Thanks Rob -

That does make sense...

The part from JimK is the copper piece that goes under a bolt head and about
6 inches of lead wire (red / black).

I'll call Applied tomorrow to ask - but I'll inquire here as well:

How do I attach this new sensor? Crimp it to the existing (cut) wires?
Twist and solder it under some heat shrink? Ugh.

Steve W
1973 23'
Southern California

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Unsubscribe or Change List Options:
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[RF_Burns]

I've haven't pulled a sensor apart, but from posted photos I believe its an active thermal sensor rather than a passive thermistor. Something like
this product here from MicroChip.

http://www.microchip.com/wwwproducts/en/en022289

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[Matt Colie]

> I've haven't pulled a sensor apart, but from posted photos I believe its an active thermal sensor rather than a passive thermistor. Something
> like this product here from MicroChip.
>
> http://www.microchip.com/wwwproducts/en/en022289

I don't know Bruce, they are on two wires. To count on the screw head that they clamped under as a signal ground is really iffy. Not that people
don't do iffy things, but if it is a chip, I'm going to go back and remove about 30 feet of wire than I have rolled up.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[johnny]

Twist and solder and heat shrink. The 'goo' is a glue which keeps water out if you obtain glued shrink. It isn't an 'active' sensor, there's no
power lead. Plus, the accuracy needed in this circumstance is easily met by a thermistor which is the least expensive way to do it. You'd need a look
at the schematic top confirm the exact setup, and the maker may consider it confidential. I'm too lazy to draw one of mine but at a glance it looks
fairly standard logic, amps, and display drivers.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[Gene Fisher]

Read here
http://bdub.net/gmcmotorhome.info/chassis.html

On Tue, May 23, 2017 at 5:58 AM Johnny Bridges via Gmclist <

> Twist and solder and heat shrink. The 'goo' is a glue which keeps water
> out if you obtain glued shrink. It isn't an 'active' sensor, there's no
> power lead. Plus, the accuracy needed in this circumstance is easily met
> by a thermistor which is the least expensive way to do it. You'd need a
> look
> at the schematic top confirm the exact setup, and the maker may consider
> it confidential. I'm too lazy to draw one of mine but at a glance it looks
> fairly standard logic, amps, and display drivers.
>
> --johnny
> --
> 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> "I forgive them all, save those who hurt the dogs. They must answer to me
> in hell" - ol Andy, paraphrased
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html

 

[RF_Burns]

That's where I saw it, on Gen's site. If you look at the bottom of Gene's page you will see it and if you enlarge and squint right, its a Motorola
MTS102. Looking up the data sheet, its basically a transistor with the base connected to the collector. The forward voltage drop through the
Base-Emitter PN junction varies with temperature. I'm sure since they have sold off just about every division, Motorola doesn't make these anymore,
but someone else likely does.

http://bdub.net/gmcmotorhome.info/chassis.html

Datasheet
http://www.datasheetlib.com/datasheet/984565/mts102_motorola-semiconductor.html

Some application data
http://www.ti.com/lit/an/sboa019/sboa019.pdf

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[SteveW]

P.e.r.f.e.c.t.

Thank you Rob, Matt, Johnny, Gene, Bruce, and the PM responders.

What a wonderful place we have here.

Steve W
1973 23'
Southern California