[NSRCA-discussion] JR DSM glitch - trouble-shooting.

Mon Apr 27 03:42:31 AKDT 2009

Not sure if this helps, but...

Since my Dad has been flying JR DSM (not sure which RX) he has had seen
ccasions of his radio glitching.  Symptoms seemed like a momemtary lockout
or erratic servo response.  Both times happened on the ground, luckily.  In
the first case it was an OS160 on a home-made metal motor mount.  The rubber
in the mount had come apart and it was rubbing metal on metal with engine
vibration.  The second occasion was on a big gasser (not his) where a
muffler had broken loose and was rubbing metal on metal.

It seems that these RX's are somewhat sensitive to onboard interference from
metal to metal rubbing.  I believe this is not necessarily an RF problem,
but maybe an IF problem freaking out the RX.

Richard Lewis

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From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Ihncheol Park
Sent: Sunday, April 26, 2009 9:20 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.

Colin,

I am not sure which regulator you have.  However, I suggest you to add a
small heatsink to the regulator if it doesn't have one already.

Team Associated as a small heat sink that is just a little bit wider than a
Jaccio regulator.

It's not so hard to cut those small heat sinks with dremel cutting tool.

Also, re-bind the RX.  My 9303 doesn't go back to mid throttle.  Throttle
stick & trim position at the time of binding changes a lot of thing.  I've
seen several cases of incorrect binding (most with trim not at the bottom). 

Ihncheol

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From: colin chariandy <cchariandy at yahoo.ca>
To: General discussion <nsrca-discussion at lists.nsrca.org>; James Oddino
<joddino at socal.rr.com>
Sent: Sunday, April 26, 2009 3:41:55 PM
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.

I noticed that when I powered down and up the Rx the throttle servo moves to
a near mid point position and immediately returns to wherever the throttle
is set. It (9303) always did that. So I think the Rx lost power and on it's
return the throttle servo did it's usual thing and rev'd the engine. It also
didnt respond from idle so maybe it is stalling.

I'll replace the servo and battery. I also noticed that the heat shrink on
the regulator was discoloured and torn so I think I'll replace it as well.

Colin.

--- On Sun, 4/26/09, James Oddino <joddino at socal.rr.com> wrote:

From: James Oddino <joddino at socal.rr.com>
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.
To: cchariandy at yahoo.ca, "General discussion"
<nsrca-discussion at lists.nsrca.org>
Received: Sunday, April 26, 2009, 4:00 PM

I don't believe a bad battery could cause the engine to rev up unless your
battery failsafe isn't set properly.  Make sure it is.   

The first thing I would look at is the possibility that the throttle servo
is stalled at low speed.  That could be pulling the battery/voltage
regulator voltage down and it could recover after you started to throttle up
and removed the heavy load.  

Finally I would run a one amp discharge test on the battery after it is
fully charged to see if the battery is near its original capacity.  The best
way to do this is to plot the voltage vs. time taking readings every 5 to 10
minutes.

Hope this helps.  Let us know what you find.

Jim

On Apr 25, 2009, at 4:30 PM, cchariandy at yahoo.ca
<http://ca.mc313.mail.yahoo.com/mc/compose?to=cchariandy@yahoo.ca>  wrote:

I had a close call today with my R921 Rx in an Integral.

I noticed on taxi out that the engine rev'd up and quickly back down without
any command. At first I thought I must have bumped the stick by accident.
Then just before take-off there was no responce from the throttle for a
second or two then it was back. I thought the 170 may have loaded up a
little and didnt respond. It did that one more time before I aborted the
flight. However, I could'nt reproduce the problem in the pits.

Before powering down, I checked for holds or fades on the data logger - nil.

Battery voltage droped from 8.2V to 7.8V and 7.6 under 1A load. When I
re-charged it took 350mA and I was only on for 3-4 mins.

Now...I did accidentally run the battery down to like 5V during winter but
it did eventually recharge.

I'm using a Jaccio perfect switch/6V regulator, Jaccio 2000mAHr (1 season

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