vdo tach repair

[BrendAn]

i have a vdo tacho that is not working in the jabiru. it runs off a sensor on the flywheel.

it has the inbuilt hour meter as well.

Can anyone tell me if it can be repaired. it doesn't power up.

i  would hate to throw it out if its just a dry solder joint or something simple.

a new one is $440 which does not bother me. its the loss of the recorded hours i would like to save.

[T510]

I have used Howard Instruments for VDO gauge repairs in the past. 

 

They can be a little caustic and I know a few people who have had personality clashes with them but in my experience they do good work at a fair price.

[onetrack]

There was a previous discussion around this same problem. The OP found a repairer in Adelaide.

 

https://www.aircraftpilots.com/forums/topic/38510-vdo-rev-counter-hour-meter/#comment-531538

 

[BrendAn]

57 minutes ago, T510 said:

I have used Howard Instruments for VDO gauge repairs in the past. 

 

They can be a little caustic and I know a few people who have had personality clashes with them but in my experience they do good work at a fair price.

i notice on this one the needle will flick up for a second when you apply power then its dead. and the hours don't come on. do think it might be just a power problem.

[skippydiesel]

2 hours ago, BrendAn said:

i notice on this one the needle will flick up for a second when you apply power then its dead. and the hours don't come on. do think it might be just a power problem.

First off - Check cables for continuity and the that all joins are clean & secure . Pay special attention to the earth (-) return.

 

After the above, if it's still dead,  you may need an electronics technician. Good luck! 😈

 

[Thruster88]

A Jab 55 here is having electrical issues, has been diagnosed as a bad fuse block. Tests fine until put under load.

[BrendAn]

I have the tacho on the bench. I get nothing when I put power direct to the terminals. The problem is in the tacho itself.

[Neil_S]

20 hours ago, T510 said:

I have used Howard Instruments for VDO gauge repairs in the past. 

 

 

I have used Howard Instruments for VDO tacho repairs too. They did a good job and charged a reasonable price.

(Their shop is an Aladdin's Cave of instruments old and new!)

 

Cheers,

Neil

[BrendAn]

36 minutes ago, Neil_S said:

I have used Howard Instruments for VDO tacho repairs too. They did a good job and charged a reasonable price.

(Their shop is an Aladdin's Cave of instruments old and new!)

 

Cheers,

Neil

Thanks niel

[skippydiesel]

On 14/06/2026 at 5:19 PM, BrendAn said:

I have the tacho on the bench. I get nothing when I put power direct to the terminals. The problem is in the tacho itself.

Not an electronics person;

My gut feeling is that just connecting the tacho to power, on the bench, is not a diagnostic action.

To find out if the tacho is working you will need to send a pulse/signal (as from the flywheel sensor). 

You will first have to assertion that the sensor (Hall Effect/Photo/Lazer) is working as expected - probably the easiest way is to temporarily wire in a "know to be working" tacho.

If the loner tacho works, then suspect your tacho but first follow my advice (above) on making sure you have good connections😈

[BrendAn]

10 minutes ago, skippydiesel said:

Not an electronics person;

My gut feeling is that just connecting the tacho to power, on the bench, is not a diagnostic action.

To find out if the tacho is working you will need to send a pulse/signal (as from the flywheel sensor). 

You will first have to assertion that the sensor (Hall Effect/Photo/Lazer) is working as expected - probably the easiest way is to temporarily wire in a "know to be working" tacho.

If the loner tacho works, then suspect your tacho but first follow my advice (above) on making sure you have good connections😈

yes. but i thought putting power and earth to it should light up the hour meter. maybe not. i don't know anything about it.

i think i will send it off and get it looked at. 

[facthunter]

Some work off an ignition lead by inductance. I doubt that would take kindly to a direct electrical source. Some Hobbs Meters work on electric power put through a U/C micro switch to Just measure AIR time. I have a good one IF anyone wants it.  Nev

[skippydiesel]

2 hours ago, BrendAn said:

yes. but i thought putting power and earth to it should light up the hour meter. maybe not. i don't know anything about it.

i think i will send it off and get it looked at. 

Give yourself the potential to save a few $$ - Check your sensor is working before, sending the Tacho for an  expensive assessment😈

[BrendAn]

23 hours ago, facthunter said:

Some work off an ignition lead by inductance. I doubt that would take kindly to a direct electrical source. Some Hobbs Meters work on electric power put through a U/C micro switch to Just measure AIR time. I have a good one IF anyone wants it.  Nev

the vdo tach has a hall effect type pickup.  the tach itself has pos and neg terminals and a sensor terminal. i would have thought putting power and earth to it would light up the hourmeter but as i said, i know nothing.

[BrendAn]

i just found howard instruments right here in Hiedleberg. i will take it to them.

[skippydiesel]

2 hours ago, BrendAn said:

i just found howard instruments right here in Hiedleberg. i will take it to them.

Let us know how things "pan out"😈

[BrendAn]

Just now, skippydiesel said:

Let us know how things "pan out"😈

will do