How To Repair A Marine Tachometer

• #ii

there are companies that can repair your tachometer. these are similar the Speedometer Service store in Milwaukee WI, or D&D Speedometer in the twin cities. however for the price of getting your old tach repaired, you can get most of a new gauge package.

• #three

Ordinarily to repair, yous remove the gauge, and requite it a "float" test. If information technology floats in the h2o, it is proficient. If non, you buy a new i.

• #iv

:laugh::laugh::express joy::laugh::laugh::laugh::facepalm:

• #7

If it floats in the water, it is expert

Or a Witch........

Concluding edited: Aug 16, 2022

• #11

sam am I The needle DOES move significantly (~60 deg) when I utilize a multimeter with diode check across the various points on the movement (sometimes up, sometimes down). I suppose this just tells me the problem is in the excursion board, right? (I've fastened pictures below.)

OMG, real clear decent pictures.!!!........Thanks JESUS!!!

Yep, (and this is a skillful matter) and are you lot 100% on a proficient signal source? That thing should work, unless. the driver IC is bad...unremarkably not though.

https://www.onsemi.com/pub/Collateral/CS8190-D.PDF

And so, a few other things to check......

Cheque the ALL the PN junctions (0.5V-0.7V) on the red circled things with your meter's diode check and make sure the IC is getting it'due south Vcc (Pin eight) and ground when 12V/Gnd are practical to the studs.

Last edited: Aug 17, 2022

• #13

Okay unless the meter movement itself is open

Had him cheque that, he'south confirmed it'due south good past the test i had him do...Run across below

sam am I The needle DOES move significantly (~60 deg) when I use a multimeter with diode check across the various points on the move (sometimes upward, sometimes down)

and the gray wire pulses when the engine is running (as measured by my "impact it and get electrocuted" meter !

This ^^^ worries me a tad, and is why I'm request him to re-check it, did it shock y'all for existent?..... Not and so certain I empathize what you lot're maxim here....Anyone out at that place know where the signal comes from? The distributor coil peradventure? Yes? Then I reckon getting a lil bite could happen as there is a flyback voltage (xc'ish volts P2P) off the coil when the points open, this makes sense then if he did. Simply, working as hard as they do/can, a front end component might have open (or shorted) and took down the input signal to the driver IC.

At any charge per unit, we'll get at that place, the move being good is a definite plus for him, the residue is piece of cake pesy.

Man I soooooo honey existence inexpensive!!!

Last edited: Aug 17, 2022

• #15

Apologies and correction to the to a higher place Incorrect information canvass..........geeesh, it was also early.

If we're convinced the signal input to the tach and wiring were all good and........

Vcc/B+ is pivot thirteen........NOT pivot 8 equally I indicated above in postal service #xi. Also check "Vreg" (pin eleven) for approx 8.5V.

If after yous ability information technology upward to check pin 13 for 12V and IF it's NOT at that place, check that zener diode (18V) and limiting resistor (15 ohms) as seen on folio 2 of the data sheet that's hanging (wired) off the IC's pin 13..........I believe (as far every bit i can see from your pictures) the tach manu followed the IC's manu'south recommendation and added it. It serves as a voltage clench to preclude over voltage on the IC from the external voltage source (your boat).

Zener's are evil diodes as they are e'er working in reverse avalanche mode, never trust them!!! I don't...

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Last edited: Aug 17, 2022

• #eighteen

Cool Beans!!

Touching the signal wire with the engine running feels like touching a spark plug, but way less painful. It'due south definitely pulsing with the RPMs. I think it does come off the coil, but I haven't verified this.

The pulsing is a skillful sign HOWEVER this doesn't concern me so much as the amplitude of said betoken and the exploded parts........Could be normal as stated, flyback voltage off the whorl volition be a tingle.

Tread cautiously Grasshopper and always remember and never forget!!

"Ane who questions his (her) findings, will never accept to purchase additional parts and finds his (her) straightest path to ones ain inner cheapest bounder (b*tch)"

....Me

Last edited: Aug 18, 2022

Source: https://forums.iboats.com/threads/tachometer-repair.737716/

Posted by: richardsondrance.blogspot.com

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