LED compatible turn signal Flasher

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rmel
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LED compatible turn signal Flasher

Post by rmel » Mon Oct 24, 2016 9:54 pm

If you converted over to LED turn signals, it didn't take long to find that the stock Pinz flasher doesn't work well.
These are thermal flashers where flash rate is a function of the number of bulbs. This is why there is a higher
flash rate when you turn on the Hazard switch. With LED the load is small compared to bulbs, so it may flash
very slowly or not at all.

Maybe you did what I did and replaced the stock flasher with one from SAV which is an 24V electronic flasher
which is not load sensitive. In principle this should work fine for LED loads -- well sort of :?
Flasher.jpg
Flasher.jpg (63.5 KiB) Viewed 1282 times
It turns out that that these electronic Flashers will trip with EXTREMELY low current at it's output terminal, well below
the current of even one small LED. I was able to get one electronic flasher to flash with a 27K Ohm resistor tied to the
output terminal which is about 1 milliampere of current -- not much.

So here's the problem with electronic flashers in the Pinz! There is some degree of leakage current in the Pinz circuit
and wiring, from the Hazard unit, older sockets and terminals, collectively throughout the system -- very tiny but enough
that these sensitive flashers false trigger with the turn switch in the neutral position -- the flasher flashes, and the turn
pilot light goes on at a rather low flash rate but it is annoying to hear and see the light. Turn the turn indicator left or right
the primary signal lights work just fine as the vastly higher load of the actual LEDs swamps out this annoying effect.

I ran into someone else with exactly the same problem and I hard of several others who have experienced this as well.
I tried a flasher I picked up off of eBay and it behaves the same way, all the manufacturers tend to clone a common
design so some are just going to be sensitive to leakage and not work properly. Ah! But there is simple fix.

What I did was to compensate for the leakage, you can do this by adding a resistor between the +V (49) terminal of the
flasher to the Output terminal (49A). The value I used was 4.7K Ohms 1/4W -- that did it. Basically it desensitizes the
flasher to low leakage but this resister is not so low it effects the actual turn signals since it's only 6 milliamperes.
A trip to Fyr's for a cheap resistor -- salvaged the flasher.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

namtinker
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Joined: Fri Jul 08, 2016 1:21 pm
Location: Alberta, Canada

Re: LED compatible turn signal Flasher

Post by namtinker » Mon Oct 24, 2016 10:47 pm

Good to know. I have the SAV unit but still use the stock lamps. They are in bad condition so the replacement led set is in a box - waiting.
I will do this fix before I switch.

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rmel
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Re: LED compatible turn signal Flasher

Post by rmel » Tue Oct 25, 2016 10:18 am

I'd be curious to leanr if you have the problem first, then apply the remedy :?

I should also have added -- where the heck does this leakage current come from?
It's called age, 40 years or so. Given time, humidity, some corrosion in the air, things
breakdown. It's not a big deal with a low voltage system, and certainly not worth the
time and effort to try to eliminate it.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

namtinker
Canada
Posts: 40
Joined: Fri Jul 08, 2016 1:21 pm
Location: Alberta, Canada

Re: LED compatible turn signal Flasher

Post by namtinker » Tue Oct 25, 2016 7:03 pm

Yes, I have two flasher units - will modify one, then compare against the other.
My 40 year old flasher unit still worked - until circumstances forced me to leave it in place when the truck was sandblasted.
Anything not bombproof sealed was affected by the dust. Took a month of rewiring, replacing, and checking to get everything functional and clean again. Lesson learned. Boy, am I glad about the wiring simplicity.
The listed replacement SAV indicator unit on the steering column works in conjunction with the new SAV flasher unit and tail lights.

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PinzHound
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Location: Castro Valley, California

Re: LED compatible turn signal Flasher

Post by PinzHound » Mon Nov 07, 2016 6:52 am

Thank You! As the 'other person' with this problem I truly appreciate your looking into this. I had the opportunity this weekend to test your solution. I was able to connect the resistor while the unit was flashing on its own. Instant cure, disconnected, it flashes, connected, it stops. My Pinz driving will be much more enjoyable without the click... click... click... click. Great!
p.s. My nearby Radio Shack had the resistor. Mike

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