VDO Tachometer help/ diagnosis

[Auto Van Buster]

Hello, Ive had a vdo tach in my 74 bus for over 30 years and it just stopped working. The weird part is, when I turn the ignition half way, the tach needle jumps clockwise all the way past the 6000 rpm position and stays there. When I start the engine, nothing changes.
Any chance there is something I can check to make sure the tach is the problem before biting the bullet and replacing it. I know these things rarely go bad. A mechanic had put on a different coil recently, but the wire is hooked up to the negative side of the coil...
Any input is appreciated.

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[SGKent]

pull the signal wire off and leave only the power, ground and light connected. See if it goes to full scale with no signal wire attached.

Have you done anything to the wiring lately?
_________________
George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[aeromech]

If you do replace it, I recommend the ones they have now that match the rest of your instruments.

https://www.justkampers.com/es/eet-41b-320-2n-tachometer-vw-t2-bay-1974-1975.html

_________________
Lead Mechanic: San Diego Air and Space Museum
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VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
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Capable of leaping tall buildings in a single bound

[crownline]

Don't forget your speedometer, looks like your going either 32 or 83 mph. They also make cleaning products
_________________
1972 Bus 1700 cc Single Carb. But not a progressive.
Barelymuvin
Wish I still had the ones I got rid of.

"It"s got some dings and dents and neither of us is going to SEMA."(Update, I went to SEMA in 2019 but the Bus stayed home)
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