Jefferson coil tester

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
Jim-B
Posts: 10
Joined: Sun Jan 06, 2019 2:39 pm
First Name: Jim
Last Name: Boyer
Location: Declo. Idaho

Jefferson coil tester

Post by Jim-B » Fri Jan 14, 2022 2:43 pm

I have a Jefferson coil tester with the power source missing. Can anyone tell me what was used to provide the 6 volts for
Testing the lamps and coil. I would think it would be a step down transformer? Did it uses rectifier?
Thanks for your input in advance.
Jim

User avatar

Mark Gregush
Posts: 3910
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
Location: Portland Or
Board Member Since: 1999

Re: Jefferson coil tester

Post by Mark Gregush » Fri Jan 14, 2022 2:59 pm

6 volt lantern battey.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Fri Jan 14, 2022 3:06 pm

I don't know exactly what was used, but either a 6 volt auto battery or a stepdown transformer ought to work. A transformer with a 6-8 volt secondary would be suitable, and to test coils, it would need to be able to deliver about 2-3 amps at the secondary. Light bulbs don't care about AC or DC or polarity, but a coil will behave a little differently on 60 cycle AC as compared to clean DC, such as that provided by a car battery. An older battery charger with a 6 volt setting would provide 6-8 volts DC, probably a pulsed DC, rectified, but not filtered. The new type chargers usually have no 6 volt setting, and they use solid state regulation and safety features to prevent shorts and improper polarity connections. I suspect that they would not work well on a T coil. A full wave, filtered rectifier is a fairly simple device, but I don't know where you'd get parts today to build one.


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Fri Jan 14, 2022 3:07 pm

If a lantern battery works, thats the ticket.


Art M
Posts: 291
Joined: Wed Jun 19, 2019 12:57 pm
First Name: Art
Last Name: Mirtes
Location: Huron, Ohio
Board Member Since: 2016

Re: Jefferson coil tester

Post by Art M » Fri Jan 14, 2022 9:09 pm

A
Four D cell batteries in series r its will work just as well.


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Fri Jan 14, 2022 9:45 pm

How much current can a new size D cell provide?

User avatar

TFan
Posts: 227
Joined: Sun Jan 06, 2019 2:24 pm
First Name: Jim
Last Name: Riedy
Location: Sandusky,Ohio
MTFCA Number: 25079
MTFCI Number: 18732
Board Member Since: 2005

Re: Jefferson coil tester

Post by TFan » Fri Jan 14, 2022 11:14 pm

This is out of a pieces/parts tester I picked up at Hershey several years ago, it has six leads coming out of it. I believe the two reds are 110v and the other four are six or twelve volt. I tried at that time to test it but kept blowing the fuse on my test outlet. I've got a couple of older doorbell transformers I might try instead. Jim
DSCN0965.JPG
DSCN0967.JPG
Measures about 2 1/2"X 3" and maybe 2" thick.
Back road kinda guy stuck on the freeway of life.

User avatar

BE_ZERO_BE
Posts: 408
Joined: Sun Jan 06, 2019 12:27 pm
First Name: BOB
Last Name: CASCISA
Location: POULSBO, WA
MTFCA Number: 16897
MTFCI Number: 16628

Re: Jefferson coil tester

Post by BE_ZERO_BE » Sat Jan 15, 2022 3:49 am

Here is a schematic I made when I restored mine.

 
Jefferson Coli Tester Schematic.pdf
(15.48 KiB) Downloaded 50 times
Respectfully Submitted,
Be_Zero_Be

I drive a Model T ... Microseconds don't matter :D

For every Absolute Model T Fact there are at least three exceptions.


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Sat Jan 15, 2022 9:43 am

It looks like the operational test applies 6 volts AC at 60 cycles. I assume the lamps are for continuity testing. The 18 volt tap is unused. It could be used to "high-pot" a coil to simulate operation on MAG.

User avatar

TFan
Posts: 227
Joined: Sun Jan 06, 2019 2:24 pm
First Name: Jim
Last Name: Riedy
Location: Sandusky,Ohio
MTFCA Number: 25079
MTFCI Number: 18732
Board Member Since: 2005

Re: Jefferson coil tester

Post by TFan » Sat Jan 15, 2022 10:06 am

Thanks for the diagram Bob. Jim
Back road kinda guy stuck on the freeway of life.


Topic author
Jim-B
Posts: 10
Joined: Sun Jan 06, 2019 2:39 pm
First Name: Jim
Last Name: Boyer
Location: Declo. Idaho

Re: Jefferson coil tester

Post by Jim-B » Sat Jan 15, 2022 11:16 am

I want to thank you guys for the information regarding the Jefferson. Coil tester. I can see I am missing
A transformer of some sort. I think I will use a small transformer, maybe 6 /12 volt unit. I realize the tester
Is basically a go- no go device but I just wanted to restore it as a working novelty.
Jim-B


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Sat Jan 15, 2022 12:09 pm

A transformer from an older 5 to 10 amp 6-12 volt battery charger would be a good choice. The crackerbox 6-12 V chargers used to be cheap, but I suppose that's changed. These newfangled chargers are so smart and safe they would probably shut down, take over your mobile device, and report you if you to federal authorities if you attempted to do anything out of authorized protocol with one.


TXGOAT2
Posts: 2013
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Jefferson coil tester

Post by TXGOAT2 » Sat Jan 15, 2022 12:10 pm

If the bulbs are simply continuity testers, you could use 12 volt bulbs and then you wouldn't need the 3 volt tap.

Post Reply Previous topicNext topic