Peter,
Don't forget that resistors come in different power ratings - using Henry's
suggestion that resistor could be dissipating 1.5 Watts. The most common
resistors with wire leads are rated at 0.25 watts. Use a quarter watt
resistor where you should be using a larger one will result in another
crispy component.
Regards,
Doug.
----- Original Message -----
From: "Henry L.Coleman" <[email protected]>
To: <[email protected]>
Sent: Monday, August 31, 2009 12:11 PM
Subject: Re: [on-asterisk] Repair of Aastra 9112i
Hi Peter, if this resistor is open circuit then the only way to know what
value it was is to contact Aastra or ...
If he resistor was in series on the AC side of the bridge rectifier it
probable acts a current regulating device
in which case the bridge recifier could have sorted and blown the resister
(like a fuse) so before you change it check
the BR. The resistor value itself can be approximated by using ohms law:
V=I/R etc.
If the device power supply is 5v at 330ma (just guessing) then the device
has an internal resistance of:
5v x 0.3amps = 15 ohms
Therefore start at that value and reduce it until the resistor gets
slightly warm over a 5 minute period
Good luck
Henry L.Coleman [VoIP-PBX.ca]
-------------------------------------------------
Peter MacFarlane<
Hi All:
I have a client's 9112i that has apparently burned its power supply
out. There is a nice crispy resistor just before the bridge rectifier
on the mainboard. Anyone ever replace this resistor? Anyone know what
size it is (was)? I think these models have an overheating problem.
I'm just hoping my lasts for a while.
Peter M.
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