Several years ago I believe I experienced this same problem. There are
three possibilities I'm aware of.
Larry Lloyd was the service manager for Airtronics until he died a year ago.
He had a LOT of experience with the Vision tx and suggested part of the
following.
1. Are you on 50 mHz and using a rubber ducky. This may apply to 72 mHz,
but I don't know because I don't have a transmitter on 72. There seems to
some indication that with the rubber ducky installed the microprocessor was
bothered by a bad VSWR when the tx was placed on wet ground or a large metal
surface (hood of a vehicle?). I experienced this with an Mueller Ellipse T
and a Mueller Thermal King back in '93. I splattered the Ellipse on launch
and could have lost the King when I got it out as a backup. The programming
was completely scrambled. Fortunately I had written down all the
information so I could reprogram the tx when I got home. I did send the tx
into Airtronics and when it was returned the rubber ducky had been removed
and a standard telescoping antenna was in it's place.
The same thing can happen if the standard antenna is not fully extended when
the tx is on!!
2. Has your transmitter experienced some vibration lately? On many, if not
all, of the Vision tx's several of the IC chips are socket mounted. It is
possible for the pins to become corroded, dirty or whatever, resulting in
poor connections. These are all low voltage signals so any problems here
show up as programs errors also. Simply removing and reinstalling the chips
takes care of this. It doesn't hurt to apply some form of 'contact
improver/cleaner' when doing this.
3. If the voltage of your tx battery goes too low, the microprocessor can
literally 'spit up', resulting in misreads of stored data and/or faulty
program processing. This is not a consistent thing, i.e., sometimes it
doesn't cause any problems, other times it does. Turning off your tx as
soon as possible after the low voltage alarm activates eliminates this
problem.
Also, as a general precaution, do not operate or even carry cell phones when
you are flying. Even though the phone is 'off', it really isn't. The phone
must regularly tell the 'tower' where it is in order for the system to find
it. There have been several cases in England where this has caused crashes.
I hope this helps.
Jim Porter
Bettendorf, Iowa USA
"Get your facts first, then you can distort them as you please."
Mark Twain
----- Original Message -----
From: "Jim Porter" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, March 17, 2000 6:35 PM
Subject: [RCSE] Vision problem
> I had the following unresolved experience when setting up a new
> glider on a FOUR MENU GROUP VISION TX.
> The new glider was on Menu Group 1 and a second glider was on
Group
> 4 ( access level 0). The new glider had been basically set-up some days
> before, with no problem. Both Tx and Rx batteries were fully charged. I
was
> operating PPM6 Rx's on ch 47..
> I was in the process of fine tuning the aileron differentials when
> all the moveable surfaces started chattering wildly for no apparent
reason.
> I switch off. In order check for a receiver problem I switched
to
> Menu Group 4 and switched on second glider which responded in the same
crazy
> manner. So it was obviously a TX problem.
> When I checked the TX I found that the programmes had changed on
all
> four menu groups.
> Some of the changes were as follows:
> PPM 6 was changed to PCM8 (I haven't used PCM for many years)
> V-Tail changed from YES TO NO
> Surface Adjustment Centres, Mixer Gains all changed to ZERO
> Presets changed to ZERO except Dual Ratios which stayed at 100%
> I then reprogrammed Menu Groups 1 & 4 and the systems are all
working.
> I spoke to Jack Albreck, Airtronics Technical Support who could
not
> account for the happening. He was of the opinion that nothing would go
wrong
> while airborne. When I suggested sending the Tx to Airtronics he said the
> problem would be very difficult to diagnose.
> I have today had the TX and RX for both gliders operating for over
> an hour each without any problems.
> I would be interested to know if any subscribers can through an
> light on this unusual event and any solutions before I get a glider
airborne.
>
> Jim Porter.
>
> .
>
> RCSE-List facilities provided by Model Airplane News. Send "subscribe"
and "unsubscribe" requests to [EMAIL PROTECTED]
>
RCSE-List facilities provided by Model Airplane News. Send "subscribe" and
"unsubscribe" requests to [EMAIL PROTECTED]
