Having the EI does influence the discussion, of course. Isn't a potentiometer supposed to divide or reduce voltage?
Replacement tachometer not working right
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Originally posted by hanleyclifford View PostIsn't a potentiometer supposed to divide or reduce voltage?
It's use would be to calibrate the instrument to various input voltages would be my guess.
TRUE GRITLast edited by JOHN COOKSON; 11-23-2015, 02:25 PM.
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Originally posted by alcodiesel View PostI can't get the replacement tach to read steadily. It'll read the rpm then sporadically jump then settle back to the correct rpm just to do it again. ...@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4
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Originally posted by alcodiesel View PostI know when a 12v auto system is running it's above 12v- maybe 13 to 14v. I am guessing this tach needs 12 or less. The instructions weren't clear- something was lost in the translation. It's a mystery.
That's why I put the resistance in the send line- I just couldn't imagine a component was made for auto/marine not able to handle up to 15v or so.
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Originally posted by JOHN COOKSON View PostYes. It's a variable resistor.
It's use would be to calibrate the instrument to various input voltages would be my guess.
TRUE GRIT
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Originally posted by hanleyclifford View PostIt appears that according to the manufacturer the potentiometer is also used to influence output voltages. Sure would like to see a link to those manufacturer instructions.
My other question is what are 2K ohms doing in a 12 volt system? Wouldn't resistance of just a few ohms drop the voltage to almost zero? What am I missing here?
TRUE GRIT
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Alco Bill, even though the chatter continues it's good to hear you reached a resolution quickly. Funny how not a single one of us advised a call to the dealer. We do get caught up with ourselves don't we?Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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Originally posted by JOHN COOKSON View PostCould be.
My other question is what are 2K ohms doing in a 12 volt system? Wouldn't resistance of just a few ohms drop the voltage to almost zero? What am I missing here?
TRUE GRIT
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AlcoTach
Hahaha, you guys are too much. I returned it. They'll send another. I'll report here.
AlcoBill-
Alcodiesel comes from one of my old hobbies- model railroading. ALCO is American Locomotive COmpany of Schenectady. Great steam engines then diesels before they went broke.Bill McLean
'76 Ericson 27
:valhalla:
Norfolk, VA
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Scary Stuff
Found some instructions from the company that makes the tach: http://www.wemausa.com/instructions/...ometer_led.pdf
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Originally posted by ndutton View PostIn basic electrical terms not specific to this instrument I'm curious how the addition of a fixed resistance resolves an intermittent problem. I suppose we should accept the manufacturer knows the idiosyncrasies of his product better than anyone else.
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Horrible customer service. WEMA USA
Finally, finally got refund for the tach I sent back November 23rd, 2015! They said it was a diesel tach even though I clearly ordered a gas one and the instructions were for gas. They said they didn't have the one I wanted in stock.
It seemed that they would do nothing till I called- repeatedly. I had them on speed dial! They kept telling me they moved. Who cares? I didn't force them to take my money.
Wow, I will never order from them again. Here's their website:
Turns out there's an auto shop http://www.autoelectricservice.net/gauges.html
selling VDO tachs way less than Defender ($112 v $140) that will work just a few minutes from my house. Sheesh.Bill McLean
'76 Ericson 27
:valhalla:
Norfolk, VA
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Diesel tachs typically have one of two input signals, alternator tap or tach generator (sender). During troubleshooting did you ever determine which input it required?Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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