Reply
 
Thread Tools Search this Thread Display Modes
 
Old 11-12-2007, 06:35 PM   #1
1 Rivet Member
 
Currently Looking...
Anaheim , California
Join Date: Oct 2007
Posts: 16
Question of the year - autofill?

Not even Airstream could help me here. I have a 1990 25' MoHo with an inoperative "AutoFill" system. Solinoid and valve work great (applying 12v with a battery), wires are fine all the way to the control panel. The AutoFill LED comes on but its not passing the 12 volts to the downstream side. As far as I can tell by eyeballing the circut design is there is a 16 leg IC, a PC mount relay (that seems to be operating), a 3 leg mosfet transistor(?) (#'s are P110 and a 839 on the face with a Motorola symbol, and along the top is 508838, non of which seem to cross refrence) then a diode on the output side. I'm getting 12v to the diode but not across it and out to the solinoid. When I jumper the diode the solinoid clicks and the system starts working but the transistor almost immediatly starts heating up to the point of smoking.
I cant find any circut design anywhere, and I hate having a nifty little feature like this that I cant use! Someone please help!!
__________________

__________________
SgtMunger is offline   Reply With Quote
Old 11-12-2007, 06:54 PM   #2
Rivet Master
 
TomW's Avatar
 
1967 26' Overlander
Huntsville , Alabama
Join Date: Dec 2003
Posts: 2,918
Images: 2
Appearing stupid seldom slows me down

I have a travel trailer, not a moho.

What are you attempting to autofill?

Tom
__________________

TomW is offline   Reply With Quote
Old 11-12-2007, 07:14 PM   #3
Rivet Master
Commercial Member
 
lewster's Avatar
 
Vintage Kin Owner
Naples, FL , Hood River, OR
Join Date: Dec 2005
Posts: 7,279
Quote:
Originally Posted by SgtMunger
Not even Airstream could help me here. I have a 1990 25' MoHo with an inoperative "AutoFill" system. Solinoid and valve work great (applying 12v with a battery), wires are fine all the way to the control panel. The AutoFill LED comes on but its not passing the 12 volts to the downstream side. As far as I can tell by eyeballing the circut design is there is a 16 leg IC, a PC mount relay (that seems to be operating), a 3 leg mosfet transistor(?) (#'s are P110 and a 839 on the face with a Motorola symbol, and along the top is 508838, non of which seem to cross refrence) then a diode on the output side. I'm getting 12v to the diode but not across it and out to the solinoid. When I jumper the diode the solinoid clicks and the system starts working but the transistor almost immediatly starts heating up to the point of smoking.
I cant find any circut design anywhere, and I hate having a nifty little feature like this that I cant use! Someone please help!!
Hey Sarge,

I'm not familiar with their circuit design, but I've been around a number of MoHos that use a simple system:

If you have continuity in the wires to the solenoid and 12VDC power near the switch, why not just bypass the circuit board with a simple 12VDC circuit that will energize the fill solenoid using an SPST relay and basic switch on the control panel? You can always run an LED indicator from the downside of the switch to tell you it's on.

Simple is good!
__________________
Lew Farber...ABYC Certified Master Marine Electrician...RVIA Certified Master Tech ...AM Solar Authorized Installation Center...AIRSTREAM Solar & Electrical Specialist...Micro Air 'Easy Start' Sales and Installations
lewster is offline   Reply With Quote
Old 11-13-2007, 10:37 AM   #4
1 Rivet Member
 
Currently Looking...
Anaheim , California
Join Date: Oct 2007
Posts: 16
Quote:
I have a travel trailer, not a moho.

What are you attempting to autofill?

Tom
Hi Tom. Some of the MoHo's and I believe even the trailers around that time had an AutoFill system so when you were connected to city water you could hit a switch and automaticly fill your fresh water tank. The system would then shut off at 3/4 tank capasity. Neat system, just a poor design, or a cheap component used by whoever designed the circut for AS.
Quote:
I'm not familiar with their circuit design, but I've been around a number of MoHos that use a simple system:

If you have continuity in the wires to the solenoid and 12VDC power near the switch, why not just bypass the circuit board with a simple 12VDC circuit that will energize the fill solenoid using an SPST relay and basic switch on the control panel? You can always run an LED indicator from the downside of the switch to tell you it's on.
Thank you Lewster.
That thought had crossed my mind. The stock system has an auto shut off at 3/4 capasity, I assume it gets signal from the 3/4 LED and shuts off the relay, but thats where it starts to get a little more complicated for me since I dont know what other system (if any) uses that Circut board. I figured if I could get away with it I'd just replace the weak link (poor quality component) in the original.
__________________
SgtMunger is offline   Reply With Quote
Old 11-17-2007, 09:00 PM   #5
1 Rivet Member
 
Currently Looking...
Anaheim , California
Join Date: Oct 2007
Posts: 16
No other electronics guru's here? Any one with experience on the stock system?
__________________
SgtMunger is offline   Reply With Quote
Old 06-01-2010, 04:46 PM   #6
2 Rivet Member
 
GJ Excella's Avatar
 
1989 32' Excella
Grand Junction , Colorado
Join Date: Dec 2007
Posts: 20
I have a 1989 32' Excella, after 28,000 mile last year, both wires to the Auto fill solenoid became disconnected. Does it matter which wire goes where?

Thanks, Joe
__________________
GJ Excella is offline   Reply With Quote
Old 06-01-2010, 04:57 PM   #7
Rivet Master
 
TomW's Avatar
 
1967 26' Overlander
Huntsville , Alabama
Join Date: Dec 2003
Posts: 2,918
Images: 2
Normally "no", but

Quote:
Originally Posted by GJ Excella View Post
... Does it matter which wire goes where?
No... Usually.

The solenoid itself could care less. "Usually" because some careful designers hang a diode across the terminals of a DC circuit to cut down on arcing across the contacts. If the wires are connected incorrectly in that situation, you will either blow a fuse or toast the diode.

If the only thing you see is two terminals where two wires go, then you are okay. Hook your wires up, and move along.

But if there is a "+" or "-" mark on the terminals, then reply back. A picture would be nice.

Tom
TomW is offline   Reply With Quote
Old 06-01-2010, 07:36 PM   #8
Moderator
 
HiHoAgRV's Avatar

 
1991 34' Excella
1963 26' Overlander
1961 26' Overlander
Central , Mississippi
Join Date: Nov 2006
Posts: 5,326
Images: 29
Blog Entries: 49
Quote:
Originally Posted by TomW View Post
No... Usually.

The solenoid itself could care less. "Usually" because some careful designers hang a diode across the terminals of a DC circuit to cut down on arcing across the contacts. If the wires are connected incorrectly in that situation, you will either blow a fuse or toast the diode.

If the only thing you see is two terminals where two wires go, then you are okay. Hook your wires up, and move along.

But if there is a "+" or "-" mark on the terminals, then reply back. A picture would be nice.

Tom
Mine does not have a diode, therfore it's not critical on the connection.
__________________

__________________
Hi Ho Silver RV! Vernon, Sarah, Mac the Border Collie -
A honkin' long 34' named AlumaTherapy http://www.airforums.com/forums/f205...num-54749.html
and a 26' '63 Overlander, Dolly http://www.airforums.com/forums/f109...ome-71609.html
HiHoAgRV is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
What Year Do I Have?? elliottkatz General Repair Forum 1 07-14-2007 10:17 AM
Where have you gone this year? wheel interested On The Road... 66 05-22-2007 10:24 AM
What a year it has been! thecatsandi Full-Timing 16 04-24-2007 09:30 AM
Engine/Year Trans/Year Matrix ViewRVs Mechanics Corner - Engines, Transmission & More... 36 10-23-2005 08:40 PM
what year are the changes? RichardT Our Community 2 05-23-2004 01:44 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 06:41 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.