dashboard resistors

[rob love]

Brian
I apologize for the late response, but I am currently wiring my mk1 dash, and was just replacing the resistor/fuze assembly today.

I got a new assembly from Mac's auto and measured the resistance of both the original and the new one. Both measured at 4 ohms. In the case of the mk1, the resistor would be for the reduction in voltage to the coil.

The screws on the new one will not be any good for the carrier (too log and too bright), so I will have to salvage the old ones. You also have to salvage the old spacer/insulator for underneath this assy. But otherwise it is spot on. FUC=03 lists it as 11A-12250 although Mac's part number is 47-14615-1 with an alternate of 40-12250-A.

[Mike Cecil]

I thought the Ford system was a (1) system circuit breaker and (2) a resistor for reduction of voltage from 6 to 4.5 volts for the coil - not two resistors.

The image shown shows a (repro?) item the same as available from Macs Ford Parts. It consists of a a fuse holder (which acts as a one-time circuit breaker) where normally a cage with a mechanical circuit breaker was located. The other end is the resistor (6 V to 4.5 V).

Or have my many years of Ford experience deserted me and I've got this completely c****d up??

Mike C

[Mike K]

Hi

One thing to watch out for is , if they are wire wound resistors ,typically made with nichrome wire , the resistance value will change as the resistor heats up . There will be both cold and hot ohm values .

You might be better off using a solid state device mounted on a heatsink .

Those Ford ignition systems are a pain in the bum .

[Lynn Eades]

I am waiting for a definitive answer to Brian's question, from someone.

Mike C. the LP2 carrier has the resistor for the coil (6v to 4.5 v) and the vibrating regulator for the generator if my memory serves me correctly.
This depends on the type of generator (2 or 3 brush) I think the other type has the cut out in the dash unit. I may be wrong about this. I can't remember.

Mike K. That is how it was supposed to work with Henry's set up.
When you turn on the key, you get 6 volts to the coil, which equals (hopefully) a big fat spark while cranking to start (It might drop anyhow because of the load)
A few seconds on, the Nichrome wire has heated up (the guard has a purpose) generating its internal resistance to flow, and dropping the output voltage to 4.5 volts, the operating voltage of the old Ford ignition systems.

Brian. I imagine you are on the right track. The Ford commercial gauges were the same for all (early?)vehicles, either 6 or 12 volt. The 12 volt vehicles had the resistors fitted to the back of the instrument cluster.
Macs sell them, and you need 3 of them for the fuel, oil, and temp gauges. I understand there is a more expensive single unit that will do all three.
Can you post photos, details (resistance) and a price for what you have for sale, please?
It would be interesting to know what the operating voltage of the T16 coil is.
If it is 9 volts, then it will have a resistor. It's all about an easy starting system.

What I learned from Mike K. tonight is that it is called Nichrome NOT the lifetimes misconception that it was Michrome wire.

BTW Rob, you can buy the Nichrome wire, if you wanted to rewind your original resistor.

[Mike Cecil]

Ni Chrome - Nickel-chromium wire, freely available in various gauges.

vibrating regulator? enlighten me, please.

The voltage regulator is a big rectangular box, on a different mount from my experience.

Mike C

[rob love]

On the mk1, according to my wiring diagram, the illustrated item serves two functions. Power comes from the ignition switch (terminal C on the switchboard) to the top of the fuse holder. From there it goes to two places. A jumper runs down from the top terminal of the fuse holder thru the resister and on to the coil. The power from the top terminal also goes thru the fuse and on to the hot terminal of the two gauges.

As a result of this setup, the gauges are protected by a suitable fuse. The coil circuit is not protected.

There is another single fuse box nearby that protects the lighting circuit. I'll try and get some photos later today. In both cases the fuses are a little different in their design, which would seem to allow the repair of them by the user.

I had a google at the part number of 11A-12250, which is what FUC-3 calls for, and it is indeed a breaker and resistor assy like I have always seen on the cmp trucks. I am not certain that part would even fit in the tight confine of the mk1 control panel. It may have been a change up from the earlier control panels as well. My original fuse holder/resistor would appear to have been on this panel for a very very long time.

[Jordan Baker]

http://www.mapleleafup.net/forums/sh...?t=2189&page=7

Post 196 has a couple of pictures off all original resistors and fuse assemblies that came out of a Mk1 dash. I cleaned them up and they worked fine in my carrier.