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

[Brian]

How about an IR temp gun to help?

-----Original Message-----
From: Ed Alt <ed_alt at hotmail.com>
Sent: Monday, April 27, 2009 5:24 PM
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>; colin chariandy  <cchariandy at yahoo.ca>; glmiller3 at suddenlink.net
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.

This is easy to resolve.  Nothing high tech is needed.  One by one, move 
your controls and carefully watch to see if it looks like the any of them 
are straining at the end of their maximum travel.  Check the throttle in 
particular.  I have seen digital servo cases melt from having the throw set 
up further than the linkage will allow.  If that's not it, disconnect the 
linkages at servo and work the control surface by hand.  If it does not move 
very freely, fix it.  If you don't find the problem there, work the servos 
around in a 10 minute mock flight on the ground, except exaggerate the 
movements considerably since there will be no air load and engine vibration 
to add to the load.  Listen to each servo.  If it sounds like it's having a 
problem, remove it and check it out on the bench.  If there's nothing 
obviously wrong by the sound of things, then feel the servo cases  to see if 
any of them are getting warm, or even try smelling them for that 
characteristic smell that hot electronics tend to have.  If there is a 
regulator that got so hot as to discolor it, and there is nothing at all 
wrong with the linkages or control surfaces, then this ought to find the 
culprit.

Ed
----- Original Message ----- 
From: "David Cotton " <davercotton at hotmail.com>
To: "colin chariandy " <cchariandy at yahoo.ca>; 
<nsrca-discussion at lists.nsrca.org>; <glmiller3 at suddenlink.net>
Sent: Monday, April 27, 2009 6:09 PM
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


You will need a very good meter to read the current, because a fully loaded 
digital setup takes the current in short spikes and most meters do not have 
a good enough frequency response. I have tried using a very good quality HP 
meter with over 20k frequency response and concluded it's not accurate, but 
it does give you a ball park number and will indicate if you have a serious 
problem. I have monitored my receiver voltage using a FDR data recorder and 
using two nimh batteries pack in parallel see at least one volt drop spikes 
at the receiver when the servos are heavily loaded.  I run 2 20amp  schottky 
diode connected packs in parallel for safety. You can be sure that these 
spikes are  5amps  or more. I placed a Castel reg in the circuit and it 
drops the spikes to a few hundred millivolts

The average current draw is around 250 mA for 2 masters sequences.

Hope this helps. Incidentally the regulator does not get hot.
Sent via BlackBerry by AT&T

-----Original Message-----
From: colin chariandy <cchariandy at yahoo.ca>

Date: Mon, 27 Apr 2009 20:40:21
To: <nsrca-discussion at lists.nsrca.org>; <glmiller3 at suddenlink.net>
Subject: Re: [NSRCA-discussion] JR DSM glitch - trouble-shooting.


Yes.

I can't find by physical inspection any "wacked out servos" or other issues 
that might cause increased current load on the regulator. So....I'm trying 
to find the typical (or average) current that should be seen at any moment 
(instant) on a meter in-line with the regulator. Then I'll run my set-up and 
compare. If I'm in the ball park (less than 1A based on a couple of inputs 
so far) then the problem is not related to "wacked out" servos, binding etc