Tach amp repair attempt - Page 2 - PeachParts Mercedes-Benz Forum

Knightrider966 · #16 05-27-2007, 07:54 PM

it is. I cannot get this forum to post a file picture of this size so all I guess I can do is send it to anyone who wants one,PITA!

300SD81 · #17 05-27-2007, 07:55 PM

upload it to http://imageshack.us and then post the url here

Knightrider966 · #18 05-27-2007, 07:55 PM

Quote:

Originally Posted by 300SD81

What type of file? Images, use http://imageshack.us , others, I can host it on my server if you want

OK, how do I send it to you?

300SD81 · #19 05-27-2007, 07:56 PM

Quote:

Originally Posted by Knightrider966

OK, how do I send it to you?

email it to [email removed]

Knightrider966 · #20 05-27-2007, 08:12 PM

OK, I could not post it to imageshack! this is basically a scanner copy of the printed image and I can't resize it to fit here, BIGGER PITA! 300SD81, I sent it to you and if you can host it on your server I'm sure the members would be greatful. I'm glad to have found this so I can share it here. I think everyone has had this problem of their RPM sensor conking out!

cewyattjr · #21 05-27-2007, 08:22 PM

I'm happy to host it as well: cwyatt at chuckwyatt.com

Knightrider966 · #22 05-27-2007, 08:23 PM

Quote:

Originally Posted by cewyattjr

I'm happy to host it as well: cwyatt at chuckwyatt.com

OK! I'll send it to you too!

300SD81 · #23 05-27-2007, 08:26 PM

here it is..

VickeryMarine · #24 05-27-2007, 08:26 PM

I will take a copy too if anyone wants to email it to vickerymarine@yahoo.com....or, if someone can figure out how to post it here, that will work too.
Thanks!
Jeff

VickeryMarine · #25 05-27-2007, 08:27 PM

Disregard, it just popped up ...thanks to 300SD81 !!!

300SD81 · #26 05-27-2007, 08:28 PM

Its not truely a schematic, the logic gates have to be implemented somehow, which is not shown.

dieseldiehard · #27 05-27-2007, 08:32 PM

I too would like to pitch in and see if it can be replicated. I believe it is simply a pulse amplifier, the tiny signals from the sender need to be raised in amplitude, then the instrument (tach on the dash) integrates the pulses into an analog for the galvanometer. ?? what I meant is there are two steps in the chain going from the magnetic revolving thingie at the harmonic balancer then those signals are converted from variable frequency to a variable analog. Called a F-to-V converter in the electronics trade
Whatever the heck it is, that VDO module is a poor design for some reason, I always suspected a diode or something cracks due to heat or vibration or a pin in the connector fails to make good connection in the receptacle, thats why putting cig butts or chewing gum or whatnot in the top seems to fix a few of the dead modules but in my experience this is only a temporary solution as they go bad again sometime later.

dieseldiehard · #28 05-27-2007, 08:37 PM

www, you don't need a gate, the pulses need to be "on" consistently. I bet the pin that gates it is grounded in the car. Someone had an idea that switching the tach off for some reason? I'd use a CMOS buffer and design out the gate function.

300SD81 · #29 05-27-2007, 09:02 PM

Quote:

Originally Posted by dieseldiehard

www, you don't need a gate, the pulses need to be "on" consistently. I bet the pin that gates it is grounded in the car. Someone had an idea that switching the tach off for some reason? I'd use a CMOS buffer and design out the gate function.

lol, I'm not that great of an electronics guy (yet), only a junior in highschool, who designs a few circuits when I need them.. never even worked with logic stuff before..

#30 05-27-2007, 09:20 PM

..