B7200 hour meter repair.

[twomany]

I "picked up" a B7200 recently and have gone over it to bring it up to snuff.
There were a few issues.

Included was a new tachometer drive and cable. The original drive was stripped, and the cable was broken.

Now, with the new parts, the tachometer works PERFECTLY!

But with some work today, the hour meter is non op. Stuck at 122.0 hours.

Is there any hope of repair? Or are the hour meters "sealed clockworks".

Hours is so useful for keeping track of service requirements.... It would be nice to have this unit functional.

Or should I just fit Hobbs.....;-)
Battery hours verses engine revolutions.......

 

[100 td]

But with some work today, the hour meter is non op. Stuck at 122.0 hours.
Is there any hope of repair? Or are the hour meters "sealed clockworks".

Was it working before? Some can be carefully pulled apart, no idea about yours, ensure it is getting power and ground when the IGN is on.
Other hourmeters are fairly cheap on ebay, not sure about OEM prices.

 

[twomany]

Was it working before? Some can be carefully pulled apart, no idea about yours, ensure it is getting power and ground when the IGN is on.
Other hourmeters are fairly cheap on ebay, not sure about OEM prices.

"Was it working before? "

Hmm. with a striped drive unit on the engine front, and a broken cable, How could I know? I assume it worked when new.

There are NO electrical connections to the hour meter on a B7200. It's all mechanical.
Just like early speedometers... ;-) Call it a "proportional indication of full engine rpm time".

 

[100 td]

"Was it working before? "

Hmm. with a striped drive unit on the engine front, and a broken cable, How could I know? I assume it worked when new.

There are NO electrical connections to the hour meter on a B7200. It's all mechanical.
Just like early speedometers... ;-) Call it a "proportional indication of full engine rpm time".

Ha, well of course you can easily install an electrical one..........I thought the tacho was mechanical, not the hourmeter!
www.ebay.com/itm/231869336069
www.ebay.com/itm/191352254979

 

[twomany]

Ha, well of course you can easily install an electrical one..........I thought the tacho was mechanical, not the hourmeter!
www.ebay.com/itm/231869336069
www.ebay.com/itm/191352254979

If it's not labeled HOBBS, I'm not really interested.

 

[100 td]

Plenty of Hobbs there too for around $12 & up inc shipping, even LCD if you like!

 

[twomany]

Plenty of Hobbs there too for around $12 & up inc shipping, even LCD if you like!

Thanks!

You might tell by the original post, I've done more than a little looking into the options.
I was really hoping for comments on the promise of repairing the original hardware.

 

[100 td]

Sorry, just had "Electrical" stuck in my head! Now if I could ask my 90 y/o father.....

 

[mattwithcats]

I have replaced a few...

If it's round, the mounting hole is probably 50-52 millimeter, and it can come as self powered, battery, or tractor powered...

Just look for one that's 12 volts DC, if it's tractor powered...

Allied Electronics has a wide range, from $20 and up...

Cool two line display, one for total hours, and a second resettable, hours since service, perhaps...?

https://www.alliedelec.com/enm-company-pc1210f0p/70271043/

 

[twomany]

I have replaced a few...

If it's round, the mounting hole is probably 50-52 millimeter, and it can come as self powered, battery, or tractor powered...

Just look for one that's 12 volts DC, if it's tractor powered...

Allied Electronics has a wide range, from $20 and up...

Cool two line display, one for total hours, and a second resettable, hours since service, perhaps...?

https://www.alliedelec.com/enm-company-pc1210f0p/70271043/

If I replace the hour meter with any of these referenced units, There will be a loss of the tachometer. That would not be an acceptable trade off.

I wonder if there is any way to repair the present all mechanical, two function instrument.
To bad "speedometer repair shops" have suffered due to this age of electronics.

 

[mattwithcats]

Egauges has a few hourmeter / tachometer combo's...

You will need-
Max RPM and diameter...

http://www.egauges.com/4K-RPM-Tach-3-3-8-p/a2c53194863-s.htm

 

[D2Cat]

Matt, that's nice especially for $115. Thanks for the link.

 

[twomany]

Egauges has a few hourmeter / tachometer combo's...

You will need-
Max RPM and diameter...

http://www.egauges.com/4K-RPM-Tach-3-3-8-p/a2c53194863-s.htm

Have any ideas for connections " Accepts inputs from most electronic controlled ignitions with tachometer output terminal"? ;-)

There are no terminals on the tach drive cable. ;=0

I suppose one could develop a pulse generator.... ahh simplicity.

 

[North Idaho Wolfman]

Talk about turning a mole hill into a mountain.
No you're probably not able to take the meter apart and rebuild it, not many are.
You have the tach working, just bolt a cheap hour meter under the hood, and check it every now and then.
It's not like you need to stare at the hour meter all the time, like you said it's just for service intervals.
And if that tractor is at 122 hours on the meter and it's a 30 to 40 year old tractor, I would highly suspect whoever owned it before you didn't give a hoot about regular service intervals!

 

[mattwithcats]

Wiring diagram...

https://www.vdo-instruments.com/med...37 -- Programmable Tach with hourmeter(c).pdf

Just like any other gauge, hot, switched, sensor, and ground...
Sensor taps into coil or alternator....

I would look for an OEM one first...

Hint - if you want to do oil pressure, the fitting is BSPT, same as Subaru's...
http://www.lmaautoparts.com/products/Gauges___Gauge_Fittings/

 

[twomany]

Talk about turning a mole hill into a mountain.
No you're probably not able to take the meter apart and rebuild it, not many are.
You have the tach working, just bolt a cheap hour meter under the hood, and check it every now and then.
It's not like you need to stare at the hour meter all the time, like you said it's just for service intervals.
And if that tractor is at 122 hours on the meter and it's a 30 to 40 year old tractor, I would highly suspect whoever owned it before you didn't give a hoot about regular service intervals!

Mountain into a mole hill? Hmmmm. The post was not about replacement with electronic units. I know how to do that.

The question is can the original units be repaired? Even if just to maintain "originality". Some people are in to that sort of thing. ;-) Perhaps there is a common fault that is easily put right.

Comments like "probably not able to take the meter apart and rebuild it" is being conservative, but adds no knowledge to this topic or this board.

I was hoping that the post would bring out references to those who have tried to repair the units successfully,... or not. The "internet" has several references to other similar situations and units where repair was possible. Go figure.

But, this is the world today. Mostly people comment based on what they know in SPITE of the topic subject. I know I do.... But every once in a while, a fella gets lucky.

If you don't know, Don't respond, It's OK. No one will hold silence against you.

Wish me luck!

 

[North Idaho Wolfman]

Thank you for the beratement and chastizing.
I simply made the comment i did because you were the one going along the line of adding or changing it and you were the one over complicating it.

But hey I'll bow out, easier on me than a bunch more worthless typing!

Have any ideas for connections " Accepts inputs from most electronic controlled ignitions with tachometer output terminal"? ;-)

There are no terminals on the tach drive cable. ;=0

I suppose one could develop a pulse generator.... ahh simplicity.

 

[twomany]

I simply made the comment i did because you were the one going along the line of adding or changing it and you were the one over complicating it.

I was NOT going on the line of adding or changing. Contributions to the thread were going there. But I made direct statements of my position. See post #1, #7 and # 10.

No one will care if you bow out. It does not seem that anyone here yet has experience to offer on the repair of these old combination units.

I'll keep my eye out for a spare. I've got too much $$ tied up in the tach drive and cable to abandon the original instrument now. Of course it's difficult to know if an hour meter works when there is no input. I might have gone a different way with such knowledge. ;-)