Author Topic: Tach amp pics  (Read 1884 times)

1980sdga

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Tach amp pics
« on: 31 March 2011, 10:47 AM »


I'm hoping that I just have a cold joint somewhere on the PCB. A couple of the joints around the "3" look a little dodgy.  There was a US nickel where the cigarette butt is supposed to be...

Anyone have any luck getting one of these working? Any advise?  I haven't tackled the component side yet.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

calvin streeting

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Re: Tach amp pics
« Reply #1 on: 31 March 2011, 10:53 AM »
I agree point near 3 is bad and maybe a few others.. clean flux and gve them all a reflow. (use lead solder, not new lead free crap, if you can)..

Good Luck

1980sdga

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Re: Tach amp pics
« Reply #2 on: 31 March 2011, 12:35 PM »
Thanks, that's the plan.  I've wiggled the dash wiring with no result and everything else is working. Even the clock!  Not sure how accurate it is  :P

The crank sensor looks OK and the little magnet is in place so I'm thinking it's the amp.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

koan

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Re: Tach amp pics
« Reply #3 on: 31 March 2011, 03:08 PM »
Many of the joints look crusty to me, I'd be doing them all, getting rid of the older solder with a sucker before putting more on.

koan
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1980sdga

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Re: Tach amp pics
« Reply #4 on: 31 March 2011, 04:57 PM »
No dice...

I soldered some of the bad looking joints and still no tach.  I may do all of them but it's not looking that promising. 

I remember reading something about a guy who actually figured out all the components and the Radio Shack replacement parts.  I'm no electronics guru though...
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

TJ 450

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Re: Tach amp pics
« Reply #5 on: 31 March 2011, 05:23 PM »
It's quite likey to be failed capacitor, although I can't remember that particular circuit.

Tim
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Big_Richard

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Re: Tach amp pics
« Reply #6 on: 01 April 2011, 02:52 PM »
It's quite likey to be failed capacitor, although I can't remember that particular circuit.

Tim

You wont, because its only fitted on diesel engine cars - they dont have ignition coil pulses to count so the tacho relies on that device to monitor the front diagnostic engine rotation sensor.

Big_Richard

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Re: Tach amp pics
« Reply #7 on: 01 April 2011, 02:54 PM »
Ive also heard that the issue can be the socket that the amp plugs into in its little housing. Im guessing the pins that grip onto the contacts fatigue over the years.

1980sdga

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Re: Tach amp pics
« Reply #8 on: 01 April 2011, 05:20 PM »
I'll check into the pins next. Wiggling it around didn't seem to have any affect and I sprayed it with some contact cleaner.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

sshanky

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Re: Tach amp pics
« Reply #9 on: 01 April 2011, 05:54 PM »
I thought it was my tach amp. I got a parts car, swapped them out, still no tach. Then, I replaced the actual tach and it worked. So, you might find that it is actually the tach that's failed.