VM1000 Memory/Battery Pack

Well it finally happened. The battery that the manual said for me to expect a 2 to 5 year life with finally gave it up last weekend after 13 years. This leaves me with basic instrument indications but no fuel usage information or memory things like recording tachometer time. I thought I had read about this issue on this board but apparently it was on the Matronics list, so I will attempt to document the battery change.

I ordered a ST M48T02-150PC1 memory chip from Digi-Key today at a price of $20.58 plus shipping. Apparently this will be a simple operation of pulling the old chip out and plugging the new one in.

A new initialization procedure will be required, as documented in the manual for first time use. Additionally I will need to plug in the total tach hours. I was worried about being able to do this but the procedure is simple and is shown on the JPI site.

ENGINE HRS RE-PROGRAMMING



To re-load engine hours, follow the steps below:

STEP 1 ? ?Accessing Set Mode?: With power off, press and hold buttons 1, 3, 5 and then turn on power. Wait until the displays start reading out values (takes about 15 seconds or less), and then release buttons.

STEP 2 ? ?Selecting decade to change?: Press button 4 once to move to the next higher decade on the digital engine hours display area. There is no visual indication of this, other than when you change the decade value (STEP 3). Pressing the button moves the selection to the left until it gets to the highest decade, after which the next press returns you to the lowest decade.

STEP 3 - ?Changing the decade value?: Press button 5 to increase the decade value as desired. If you go over ?9? it will carry to the next decade. To erase the entire engine hour?s value, select the highest decade and increase it until the display clears. Do this TWICE, and then proceed per steps 1 thru 3.

STEP 4 ? When you are satisfied with what you see, shut off the VM1000.

If I have any difficulties making the change I will pass them along.

Larry,

I'm at about 13 years too, and my fuel burn no longer resets to zero after each flight. Still researching, but hoping its not the first indication of impending battery doom. Will need to change it though, so very interested in your experience!

Thanks for the digi-key part number! If you can post any lessons learned on the chip/battery swap, it would be most appreciated! Do you think you will be able to make the swap in place, or will you need to remove the DPU, and thus need to disconnect all the sensor wires?

Thanks for blazing a path!

Cheers,
Bob

rvmills said:

Larry,

I'm at about 13 years too, and my fuel burn no longer resets to zero after each flight. Still researching, but hoping its not the first indication of impending battery doom. Will need to change it though, so very interested in your experience!

Thanks for the digi-key part number! If you can post any lessons learned on the chip/battery swap, it would be most appreciated! Do you think you will be able to make the swap in place, or will you need to remove the DPU, and thus need to disconnect all the sensor wires?

Thanks for blazing a path!

Cheers,
Bob

Click to expand...

I hope I don't have to remove all those wires but will just have to see.

I have recently blazed this path! I even took some pictures to document the experience. Changing the battery chip is easy once you have the box out of the plane, getting mine out of the plane was not pleasant! Reloading the tach hours and fuel tank total capacity is easy and works per the instructions. I will post try to post some pictures tonight on this thread to illustrate where the chip lives and how to get at it.

Bill York
N477DH RV-6
Chandler AZ

n5lp said:

I hope I don't have to remove all those wires but will just have to see.

Click to expand...

Me too. Talked to JPI today, and was told the fuel burn not resetting is the first indication of impending batt failure, and the tach time (mine is still OK) is next.

So Larry, are you saying that all indications other than memory items (Tach and Fuel Burn) will continue to work even if the battery dies? The unit will not go blank...no danger of losing MP/RPM, temps, etc? Just trying to decide whether to do the battery before our upcoming formation clinic...if all normal indications remain, might wait, so I don't induce a failure by tinkering before the clinic!

JPI said the batt access is on the back of the DPU, so it may mean a wire pull exercise. JPI's bat sells for $40, so the digikey looks like a good deal. Do you know if its the same quality item Larry? (Heck, it may be the same item, eh!)

eaglen92ce said:

I have recently blazed this path! I even took some pictures to document the experience. Changing the battery chip is easy once you have the box out of the plane, getting mine out of the plane was not pleasant! Reloading the tach hours and fuel tank total capacity is easy and works per the instructions. I will post try to post some pictures tonight on this thread to illustrate where the chip lives and how to get at it.

Bill York
N477DH RV-6
Chandler AZ

Click to expand...

Bill, any pics or clues would be a great help! Thanks!

rvmills said:

Me too. Talked to JPI today, and was told the fuel burn not resetting is the first indication of impending batt failure, and the tach time (mine is still OK) is next.

So Larry, are you saying that all indications other than memory items (Tach and Fuel Burn) will continue to work even if the battery dies? The unit will not go blank...no danger of losing MP/RPM, temps, etc? Just trying to decide whether to do the battery before our upcoming formation clinic...if all normal indications remain, might wait, so I don't induce a failure by tinkering before the clinic!

Click to expand...

I can only say what happened to mine. The first indication of trouble was when I turned the master on to check how much fuel I had on board I saw that that function was not working. The next indication was a single needle display instead of the sweep display for all the different engine parameters (this is a choice that can be made during initial setup). Fuel flow and pressure, oil pressure and temperature, MP, CHTs, EGTs, RPM, voltage and current displays all worked fine. Tach time was on zero.

rvmills said:

JPI said the batt access is on the back of the DPU, so it may mean a wire pull exercise. JPI's bat sells for $40, so the digikey looks like a good deal. Do you know if its the same quality item Larry? (Heck, it may be the same item, eh!)

Click to expand...

I don't know but seriously expect that it is the same part.

Thanks Larry...much appreciated!

Cheers,
Bob

Gentleman,

Here are the pictures I promised.

The access to the battery can be had by removing the panel from the bottom of the box by removing four countersunk screws. For me I had to remove the box from the plane as my wiring did not have enough service loop for the box to be unscrewed from the airframe and then rolled over.

This is a picture of the bottom of the box and the four screws to remove




Next picture is what you see when after removing the panel. The battery chip is the second chip like component down from the upper right corner of the board.




Close up shot of the battery chip still installed, you should be able to make out the ST label on it.




This last picture shows the socket that the battery chip plugs into (chip removed).



Hope this is helpful.

In the process of getting my VM1000 fully operational I have learned some other things related to the backlighting and the displays. Please feel free to contact me by PM if you are having any problems along those lines.

Fly Safely,
Bill

Great post Bill, thanks! Sent you a PM.

Same part number on the chip as yours Larry. There's 4-5 gallons worth of gas in savings! (Thanks!)

Cheers,
Bob

eaglen92ce said:

Gentleman,

Here are the pictures I promised. ..

Click to expand...

Thank you for the very good photos Bill. It looks like I will be able to change mine without disconnecting anything.

Thanks for all of this great info. I only see the VM1000C on the JPI site. Does that same information apply to the VM1000 or am I not seeing the link?

Easy

Thank you everybody that gave the information and photos that made an impossible job easy.

I should just resolve at the beginning of any under panel job to get in the full "position." It's hard for an old guy to do it more and more but it sure makes things easier when you get down there.

I had big service loops so I all had to do is remove my hinge mounting system that was preventing the back from coming off the box. The method for programming the tach time was slightly confusing to me because of some of the language in the instructions. When you get into programming mode pressing the "4" button will increment the tenths of hours. "5" will go to ones of hours without showing you then "4" will increment the tens of hours and so on.

I have been worrying about this little job for way too long. It's like usual; what you think will be hard is easy and what you think will be a snap turns out to be near impossible.

Thanks for the update Larry. I crawled under for a look yesterday too. I may have enough loop to rotate the box up 90 deg, but won't know till I try. It'll probably be worth a few Advil after, but that's the cost of panel work, eh!

Ordered the part today (thanks for that info too).

Cheers,
Bob

You guys are lucky (or well planned out)! I actually switched my DPU out with a newer version (mid 2000's). The later version DPUs use two D-sub connectors for all the sensor wires. It is actually a nicer system but re-terminating all the wires while in "the position" under the panel was definately a painful experience! At least in the future the job will be pretty easiy, just unplug the D-subs and pull the box out of the airplane.

I have D-Sub envy Bill! We'll see if I'm lucky when the part comes in!

Cheers,
Bob

The first thing I noticed is the loss of fuel flow. Does anyone know if this is battery related or something worse? I soldered the connections at the flowmeter because someone told me that they were very sensetive to bad connections.

I have also lost the ability to add fuel and the fuel remaining is always at zero. The tach hours are gone also.

Ordered the Digikey battery and will take my life in my hands and dive under and see if the service loop I put in the mass of wires is large enough. I have a spare flowmeter and will check the million wire screws when the thing is out.

I put a JPI 930 in a Reno Racer a couple of years ago and fell in love with modern cannon plugs. The instrument can be out in minutes.

Bruce Patton

bpattonsoa said:

The first thing I noticed is the loss of fuel flow. Does anyone know if this is battery related or something worse?...

Click to expand...

I don't know, but I did have a fuel flow sensor failure early on. When my battery went bad on the VM1000 recently the fuel flow was still working, but I was getting the flashing warnings on the display because of the loss of remaining fuel capability.

My fuel flow did not work before changing out my battery, and there was no improvement with the new battery! Still non operational. Have heard as stated previously that some have had moderate success with soldering the connectors and I plan on trying that next annual condition inspection.

Another new VM-1000 battery went in today, and like Larry and Bill said, all too easy (now where's that wood I need to knock on! )

Four allen screws to get the DPU loose from the sub-panel, rotate 90* (had the service loop...whew!), then 4 screws for the back, and there were the guts...just like your pics showed Bill...thanks!

Battery chip was a bit pesky to remove (while in that upside down postion) , but a little rocking, then a small tie-wrap looped over one edge (under it if you're working right-side up), and out it came. Was a bit worried that there is no polarity to the battery (symmetrical legs into the pc board), but took my best guess based on the labeling, and it works! So far anyway!

Reset the fuel max load, and the tach time. Took me a bit of brain-wrangling to figure that "decade" (from your post Larry) means 1's, 10's, 100's etc on the tach. And it is funny that pushing button 4 moves from 1's to 10's to 100s, but ya can't tell until you push button 5 and make the number increment up. Its not like a watch, where the value you are changing flashes (just a note for future users/viewers of this thread).

So far the numbers are holding...now I just need to fly it to see if F Rem/F Burn, etc work correctly.

Seems that things begin to fail on the VM as the battery ages. Fuel burn not resetting was my only inidication. Fuel remaining and fuel burn still worked, and tach time never went to zero. Was probably comin' soon.

As for FF, it worked throughout, and I would think that since its not memory related, issues there are separate from the battery. I've had RPM and FF glitches in the past, and its always been connections (FWIW). Mine were in spade fittings, since replaced. Its also worth checking the myriad of terminals on the DPU, to make sure those aren't working loose (been there too!)

Thanks again for all the help with this...made the job a non-issue (looking for that wood again! )

Cheers,
Bob

I just completed the battery change on my -6A with the black and white VM1000. The Digikey part number is right for the 1000 and 1000C.

Pulling the chip was a bit hard, just grip it with pliers and pull straight up. Be very careful alligning the pins when inserting the new one. The PC board has an outline of the chip including the mark on one end that matches the chip. Reprogramming the hours and fuel goes easily.

Alll the wire screws were looser than when I installed it, got about 1/8 to 1/4 turn on each one.

Had a brief panic when I turned it on the first time and the monitor did not light up. Helps to remember to plug in the display!

Don't know if it solved the fuel flow issue, I am doing the nose gear replacement this annual and it would be hard to run it with the front end supported by a box.

Bruce Patton

bpattonsoa said:

...Had a brief panic when I turned it on the first time and the monitor did not light up. Helps to remember to plug in the display!...

Click to expand...

Oh, that happened to me too. I just don't mention those sorts of things in public.

Another Data Point

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I just got off the phone with Digi-Key, trying to order the part number referenced at the beginning of this thread. The kind lady at Digi-Key says the part number is no longer valid, and their Digi-Key replacement part number is: 497-2825-5-ND. Same price. I will be under my panel next week, hoping the wires I originally made are long enough to turn my box over. My VM-1000 was purchased new in 1998. My battery just now died. Thank all of you that posted the pictures and information on the repair. That will make it so much easier for the rest of us!

Jim Baker
RV-6
N699JB
Just back from Bahamas RV-Flyers trip!
http://www.vansairforce.com/community/showthread.php?t=72350


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