Tach went bonkers

[bonal]

On our last trip home the tachometer went all the way around to the peg. Run up was normal climb was right on 2700 then when I was going to start adjusting the prop the needle was pegged. Just wondering what kind of failure would make it do this. I would think if it failed it would just go to the peg on the low side. Obviously it will be replaced but just curious what might make it go the other way like it did. When I tapped on it it would drop about 500 rpm but would go right back to the peg. 

[RLCarter]

sounds like tach time or maybe rebuilt 

[carusoam]

Tach cables get worn over time...

Order up new tach cable...

The signs of it failing are the sound of it winding up and letting go... repeatedly

When the needle hits the peg... it will pop the needle off its stem...

 

Sound like first hand experience, for a PP?

This is when the EI tach gets a good look.... or even a good primary engine monitor... if the upgrade account has AMUs in it...

Best regards,

-a-

[bonal]

just ordered an electronics international digital/ analog from spruce after discussing with my IA. God what's the world coming to a digital instrument in Snoopy.

[toto]

For what it's worth, these apps are surprisingly accurate, and nice peace of mind if your tach goes inop during a flight... Well worth having one around. 

(The Android one is free.. the iOS one is kind of expensive, but works equally well.)

https://play.google.com/store/apps/details?id=com.javiery.rpmgauge

https://apps.apple.com/us/app/engine-rpm/id340401811

[bonal]

My wife tried to pull one up but we were already at 6500 ft and had no service 

[toto]

55 minutes ago, bonal said:

My wife tried to pull one up but we were already at 6500 ft and had no service 

Unfortunately, I didn't have an app either when I lost my tach. But I've carried both of these apps on every flight since then

[bonal]

Pirep on the new digital tach. Took just under a week to receive from Aircraft Spruce. Was pretty easy to install especially since I still have the stock windshield with avionics access panels which made it easy to reach the tach and ignition switch.  It's been a couple flights since it's installed and am getting used to it. I like the mag drop feature. You press both buttons and it goes to zero then when you cycle each mag it reads the actual rpm drop. The LED light ring gives it a kind of analog feel. So far I'm very happy with the quality and performance. And as a primary replacement the price was very reasonable.