Tach By Lee/GMCTD

[mhagie]

YEHAA, I now done got tach, found problem, it was the dip switches on tac, it appears that they were reversed in mfg, after setting them to the 4cyl mode it started working. it was bonkers on the 8cyl mode.
Had 2400 rpm with 4 pulses in 25 ms as per Dr. Lee article,all is well now.
Now its time to build the real thing vs the breadboard, gmctd mentioned a plan to build the permanant version so I am ready for you to expound on it a little if you will please.
Thanks to all,............Merle :D :D


bty gmctd does the verse, (bad boys rape our young girls but violet gives willingly) mean anything to you ? the guy that helped me said you probably would.

[gmctd]

Yeh...I was the one she wouldn't! But that's another story. ;)

0 1 2 3 4 5 6 7 8 9
Blk Brn Red Orn Yel Grn Blu Vio Gry Wht
RIA color code

The other 'code' is no longer politically correct, don't you know!

Good news on the tach - when I sugg a ckt to Dr Lee, I had been working with FET's so long I had forgotten Base-drive requirements for bipolar devices, so his did not work well, either.
Ph.D's don't fall off turnip trucks, so wasn't long before he had bipolar transistor design in his hat!
Kudos to 'the Kid'!

Well, enough of that political pandering..... ;)

transistor on it's back, plastic side up, legs toward you
Base = left Collector = center Emitter = right

Place the 15k resistor (brn grn orn) on the metal transistor tab, folding the leads down alongside the body so one is parallel with the BASE lead, the other one with the EMITTER lead
Form a small hook at 90deg in the resistor leads, placing one on the BASE lead and one on the EMITTER lead
Attach a black wire to the EMITTER lead, and solder - this will connect to ground

Place the 220k (red red yel) resistor on the transistor body, parallel to the left side edge
Form similar hook in one shortened lead and hook it around BASE lead

Place the 1k (brn blk red) resistor on the transistor body parallel to the right side edge
Form similar hook in one shortened lead and hook it around COLLECTOR lead
Attach a yellow wire to the COLLECTOR lead, and solder - this will be Tach Drive Output to the tachometer

Connect the upper 220k lead to the upper 1k lead
Attach a red wire to these leads and solder - this will connect to the +12v power source

Place the 2.2uf cap between the 220k and 1k resistors on the transistor body
Form similar hook in the lower lead, wrap around the BASE lead, and solder all leads
Attach a green wire to the upper lead and solder - this will be INPUT from the ESS on the vac pump

Should have one lead from the 15k, one lead from the 220k, one lead from the 2.2ufd cap on the Base lead

Should have one green wire on the 2.2uf cap lead - INPUT

Should have one lead from the 1k and a yellow wire on the Collector lead - Tach Drive

Should have one lead from the 15k and a black wire on the Emitter lead - ground

Should have one red wire connected to the 220k and 1k leads - +12v

Make sure nothing is touching that should not be, then RTV the assembly to make it sturdy.

Connect and enjoy!

[ 12-06-2003, 04:12 PM: Message edited by: gmctd ]

[gmctd]

See the above edited post