Mopar Muscle Association UK

Bought a nice old Sun Tach at the HRD`S but reading various wireing links and inside the back of the tach itself, it says to use either the EB or WPA transmitters. Needless to say I dont have either so was wondering if there was any way of wiring it without or using some other piece of electronic wonderment.

Mate thats a Blue question...
he's probably got what you need or can tell you what you need.
I think its a EB-9A transmitter for 8cyl 12v car


HERE
http://www.ebay.com/itm/Vintage-Sun-Tac ... 0966505544

Yeah thanks mate, already asked blue ...... thought exactly the same as you but even he wasnt sure. wondered if Dave 999 may have known a trick on the wiring side (may have to post it to him for a tinker)

Those bloody boxes add cost to the "what I thought was a good price" peice of kit, plus being old you dont know if their gonna be ok

http://www.williamsons.com/tachphotos.htm

http://www.leverfamilysite.com/images/P ... ter_EB.pdf



OK sun tach made before 1967 needs a transmitter
after that time the tach was a solid state device and all the gubbins in the transmitter was changed to a transistor and a couple of diodes mounted in the head

the transmitter internals are shown in the picture

as you can see its a simple circuit that causes the relay to close when the coil back emf occurs

when they relay closes the 2.74 volts ffrom the 2 batteries are sent to the tach

i'd guess the tach triggers on a 3 volt square wave.

the batteries are obsolete so you would need to replace and possibly solder in some modern litium iron rechargabel AA batteries that punt out about 1.25-1.4 volts

or build the circuit in picture 2 and use it instead of an orginal transmitter

a company called williamson will convert mk 1 sun tachs to mk 2 spec

nobody knows how they do it but i'm guessing its dead simple but they hide what they have done by filling your tach head with potting mastic

sun tachs had a weight on the pointer it was used to pull the pointer higher than it should be driven by the pulses from the transmitter at RPMs above 3000 this was becasue the transmitter was rubbish at high rpm and short dwell

any converted or DIY triggered tachs need the weight removed...

which is most likely to screw the tach...

akin to doing dentistry on a bee armed only with a hammer


Dave

Dave , John would have to spend money....he dont like doing that

Could buy a converted one and melt the mastic out to see what they have done

Lots of potential to cash in for a little outlay

Wow now Im stumped........

use a pair of watch batteries or AA batteries stacked to make 3 volt cell

connect the bottom to the meter negative

and ping the positive wire from the battery off the + by jiggling alot across it with the bare end...you need to do 2 -4 jiggles a second to maintain a 200 rpm

if the neddle jumps in a small and flaccid way your tack works and it is worth while investing in

DO NOT CONNECT THE + and leave it

PS sent you a quick note on how to make a circuit on bread board or tag strip, easier on tag strip if you can't solder neatly.

bit more in keeping with age of car as well

Dave

Dave999 wrote:use a pair of watch batteries or AA batteries stacked to make 3 volt cell

connect the bottom to the meter negative

and ping the positive wire from the battery off the + by jiggling alot across it with the bare end...you need to do 2 -4 jiggles a second to maintain a 200 rpm

if the neddle jumps in a small and flaccid way your tack works and it is worth while investing in

DO NOT CONNECT THE + and leave it

PS sent you a quick note on how to make a circuit on bread board or tag strip, easier on tag strip if you can't solder neatly.

bit more in keeping with age of car as well

Dave

Love your "quick note" Dave your a star but far too complcated for the likes of me lol

just like airfix mate

download a list of circuit symbols and a resistor bands chart

can't go wrong

anyway PMed ya

work out if the tach works ....

Dave