From: Bjorn Brandstedt (super_deuce@hotmail.com)
Date: Mon Mar 08 2004 - 05:46:14 PST
Willie,
In the process of researching a recent article for the MVM magazine, I
obtained several faulty flasher units from some of our fellow list members
(Thank you!). These flashers were taken apart and the circuits were
extracted. I found that the older flashers (from the 1960's) were much
better engineered and actually would survive short circuited loads (=lamps)
long enough for a circuit breaker to trip. They were built to "mil spec"
with approved components etc. Some of the newer designs, however, are very
likely to blow immediately when the load is shorted. Some have a kind of
short circuit protection in that they will not turn on if the load is
shorted to ground, but will blow if the short occurs during the "on" time.
The 15 amp transistor in the new units can barely handle the inrush current,
which may be in excess of 20 amps for a period of time...
You should be able to purchase flasher units from several dealers, including
Memphis Equip. Price is about $45.00, I think. Also look for them on ebay.
To check for a short circuit in the turn signal lamp circuit, unscrew the
flasher connector, put the turn signal lever in "4-way flasher" mode and
measure the resistance between pin "A" on the flasher connector and
chassis. You should not have a reading below about 1 ohm. The cold filament
resistance is about 1 to 2 ohms (I don't know exactly, but it should not be
less than 1 ohm).
If you are restoring a vehicle to 1960's technology, you should try to find
the original flasher unit as well. They look slightly different compared to
the new ones. They are usually depicted in the manuals from that period. The
heat sink is not continous across the top, the flat part allows space for
the heavy duty 40-50 amp SCR used in those flashers. You may be able to find
them as "take-offs" for less than the new ones.
Personnaly, I think that the new flasher designs are an insult to the
original designers, who put a lot of engineering effort into their product
to meet military requirements. The new units can be put together by any
hobbyist with parts from any Radio Shack store (no mil-spec parts
here!)...and then conveniently hidden in a few ounces of black epoxy
encapsulant.
If you have any further questions, let me know.
Have a great day!
Bjorn
MVPA19212
Blue Ridge Mountains of Virginia
>From: "Willie McClain" <wiandci@comcast.net>
>To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
>Subject: [MV] m35 turn signal problems continue
>Date: Sun, 7 Mar 2004 21:00:05 -0500
>
>Thanks to everybody that replied. First thing I did was clean the ground on
>the steering column. Then I cleaned the ground wire that comes out of the
>back of the plug at the solid state flasher unit. Used new nuts and bolts
>to
>remount the flasher. They had allot of corrosion. I also made up a ground
>wire from the bolt on the flasher to a bracket that's bolted to the frame.
>They are still real dim. I took the turn signal flasher apart and cleaned
>the contacts. That didn't help either. Could it be the flasher unit or do
>they quit working all together when they go bad ? Can the three lever
>switch
>be taken apart to see if there's anything wrong with it ? I found the three
>lever switch for sale for $59.00 but couldn't find anywhere to get the
>solid
>state flasher. which should I get first ? Is there anything else that I can
>check ? Thanks again for all the help, Willie
>
>
>
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