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VM1000 replacement and reset tach

Posted: Thu Apr 16, 2020 3:41 am
by perossichi
Can folks advise where I get a VM1000 battery replacement? I saw a post by Lance Murray on the need to replace battery, but not where to get this.

Also, are there posts on resetting the tach value so that it doesn't zero out?

many thanks

peter r

Re: VM1000 replacement and reset tach

Posted: Thu Apr 16, 2020 4:13 am
by Steve
This is a very good explanation of the battery replacement:

http://eaaforums.org/showthread.php?163 ... amp-Busses

I get my replacements from Newark Electronics:

https://www.newark.com/stmicroelectroni ... 8T02-70PC1

Here is the procedure to reset the Tach Time:

https://vmsupport.weebly.com/--how-do-i.html

It is an easy job if you are comfortable working with electronics. I am, and have done it twice so far in my airplane. The hardest part is getting the digital box out of the airplane, as some of the fasteners are tough to get at...

Steve

Re: VM1000 replacement and reset tach

Posted: Sat Apr 18, 2020 5:10 am
by perossichi
Steve
Many thx.

Did you need to reset time or does the chip come preinitialized?

I used to have a business in the 1980s and 1990s selling EPROM chips for PCs that had special scientific character sets. So this looks like a trip back in time.

Re: VM1000 replacement and reset tach

Posted: Sat Apr 18, 2020 1:51 pm
by Steve
Peter: You will have to reset the Tach Time, as the chip is blank. It isn't difficult.

Re: VM1000 replacement and reset tach

Posted: Sun Apr 19, 2020 6:37 am
by perossichi
Steve

I’m sorry. I didn’t make myself clear. The chip includes a clock. I assume the date and time do not have to be set. Tach time obviously has to be set.

Re: VM1000 replacement and reset tach

Posted: Sun Apr 19, 2020 2:48 pm
by Steve
The VM-1000 does not display date or time, so no.

Re: VM1000 replacement and reset tach

Posted: Sun May 24, 2020 9:10 pm
by jwx96
I had the battery chip replaced 1 year ago when I had my GTX345 installed. My avionics shop (Modern Avionics in Eden Prairie, MN) followed the instructions in the references listed above. The replacement went fine but they were unable to reset the tach using the instructions. Each time they tried, the clock advanced by .1 hr and they stopped when they got to .7 hrs. That’s not really a problem. They made a note in the logbook and now everyone records tach time and TTAF. For many planes the tach time and TTAF are the same, but for my plane TTAF is the tach time before the battery change + the new tach time +.7. TTAF is the time that really matters. With that said I would be interested to hear from anyone who recently had success resetting their VM1000 tach. Also, I talked to a Diamond service center in IL that operates 2 2003 DA 40’s and they said their planes have never had a VM1000 battery change.