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It works great!

Posted: Sat Jun 20, 2009 12:25 am
by Ruffrider
Thanks Mike for the great schematic and pics. Installed one today on my 75. I had to bone up on my soldering skills though. This solution is a lot less cumbersome than dealing with a POT. Oh by the way, nice bike you got there. :-D

Posted: Sat Jun 20, 2009 2:27 am
by torgo
You can buy a 7V Regulator from Mouser http://www.mouser.com/ part number 755-BA17807T This eliminates all the resistors and most soldering.

Posted: Sat Jun 20, 2009 11:49 am
by Mike Toon
True there are 7V regulators available, but being impulsive I wanted to make one in a few minutes and had the parts. I love Mouser, their no minimum order and quick shipping though.

These parts are available at Radio Shack for someone that doesn't want to wait for mail order. National Semiconductor LM317 regulators have a nice feature, if overheats it will shut down. Recovers when cools down.

7v Regulator

Posted: Mon Jul 27, 2009 12:43 am
by doncoyote11
Last year I installed a 6v regulator from the dashboard of an early 80's or seventies Ford. They have an adjusting screw on the back so it can be changed to 7v. These units don't actually change the voltage to 7v, but rather pulse the 12 v to simulate the 7v.
I filled the tank and adjusted the regulator till it read full. Also the unit MUST be grounded, (I burned my first one up).
These can be picked up from a self-serve junkyard for a buck or two.

Posted: Wed Nov 25, 2009 11:44 am
by 78AZWing
Nice hinge pin!

Posted: Wed Nov 25, 2009 11:45 am
by 78AZWing
torgo wrote:You can buy a 7V Regulator from Mouser http://www.mouser.com/ part number 755-BA17807T This eliminates all the resistors and most soldering.
OOOH! :shock: Toy Store!

Posted: Tue Dec 15, 2009 4:23 pm
by rdurost
Mike Toon wrote:Satisfied it worked, I gutted the old regulator and used epoxy putty to fill and hold things together. Installed back in stock place.

I had the parts, but bought at Radio Shack, about $3.00

Image
Can we have an update on this? I used to be an electronics technician before I got into computers, and all the three-terminal regulators like this that I used generated a substantial amount of heat. I wouldn't expect them to last if they didn't use a heat sink, let alone were potted in epoxy.

Richard

Posted: Tue Dec 15, 2009 4:33 pm
by Mike Toon
I never experienced any excess heat. Warm but not hot. I ran it for a day, checking it often, then enclosed it. Ran almost a year without problems, then sold the bike.

Posted: Sat Dec 26, 2009 4:08 pm
by Dave_J
I have done a few of these for old Mopars that require 5 Volts for the gages. I also used some capisators to remove some of the ripple pulse to make the gages more steady. The old points voltage regulator on these old cars were very ripple pulsed and you could see the gages quiver.

These Transistors need a heat sinc to cool them down. They will be more steady when kept cool. Hope they burn out open and not closed. Open means no voltage, closed means a full 12 Volts hitting your gages. I'd just use a dielectric glue to glue an alumumn heat sinc on the back. DaveJ

Re: 7V Regulator

Posted: Tue Jul 06, 2010 7:10 pm
by Composed
Dave_J wrote:I have done a few of these for old Mopars that require 5 Volts for the gages. I also used some capisators to remove some of the ripple pulse to make the gages more steady. The old points voltage regulator on these old cars were very ripple pulsed and you could see the gages quiver.

These Transistors need a heat sink to cool them down. They will be more steady when kept cool. Hope they burn out open and not closed. Open means no voltage, closed means a full 12 Volts hitting your gages. I'd just use a dielectric glue to glue an alumumn heat sinc on the back. DaveJ
I was very happy and amazed to find this thread after driving to my local dealership and finding that the 7 volt regulator at today's price is $155.89 before tax. I drove to my local Radio Shack and found that the parts for this project were only a little over $5.50, so building this regulator appears to be a no brainer.

Dave J, do you have any suggestions as to the proper protection in case the transistor was to fail open. I'm assuming that there are fuses in this range that can be placed inline, but do you have any suggestions? What type of capacitors do you think should be used with this regulator?

Re: 7V Regulator

Posted: Fri Aug 27, 2010 6:10 pm
by matalex60
I just ordered this setup from dimension engineering. What, if anything, do I need to do to make the voltage adjustments? Can I just install it fill the gas tank and adjust to read full, and cold for the temp side?

Re: 7V Regulator

Posted: Sat Aug 28, 2010 9:16 pm
by rdurost
matalex60 wrote:I just ordered this setup from dimension engineering. What, if anything, do I need to do to make the voltage adjustments? Can I just install it fill the gas tank and adjust to read full, and cold for the temp side?
I'd start by just adjusting it to 7V no-load before installing it, then tweaking it to attain 7V under load. Once you're there, if the gauges are in the ballpark I'd ride it for a while before making any further adjustments.

Richard

Re: 7V Regulator

Posted: Mon Sep 06, 2010 2:53 am
by matalex60
Not to sound like a retard, but how do I make the proper adjustments for no load and underload?

Re: 7V Regulator

Posted: Mon Sep 06, 2010 1:23 pm
by Cookie
The ones I made did not need adjustment. One leg controls the voltage output and the resistance it gets is the control. If folks have spec ed the proper components and you installed them right you should come out about right. There are also adjustable regulators you can buy that are a bit more expensive.

Re:

Posted: Mon Sep 06, 2010 2:03 pm
by Mike Toon
rdurost wrote: Can we have an update on this? I used to be an electronics technician before I got into computers, and all the three-terminal regulators like this that I used generated a substantial amount of heat.
Well, you being an electronics technician and me being a plumber, should know better than I. It's been a few years and I'm told mine is still working just fine. The fuel gauge draws very little current. My advice is to make one from RS parts and try it. For the price of a cheeseburger your gauge could be working this afternoon.