[ICOM] my PRO III shut down problem

[hamop]

Tony.
    Yes, tried RF drive at different levels but admit did not do it at just 
20% range. Tomorrow will do that. Have tried the 100w and down to 50w and 
still goes off within a few seconds of CW xmission. Tried with dummy load as 
someone suggested and I had already done that, despite a 1:1 of antenna.  NO 
difference with dummy load, so the antenna is not an issue and SWR has 
always been fine. I use the menu to show ALC, PWR, and SWR simultaneously on 
large screen scales and there is there is NO creep of anything, all go away 
at same time, the ALC and PWR %.  Still have about 5 watts output and it CAN 
be  varied to "0" with full CCW. So, can go from 0 to about 5 watts only. 
Still, not enuff to really get power to SWR monitoring circuitry.
  The Icom PS do not have current meter in the unit like a stand alone 
Astron etc. I guess there could be a PSU shutdown from something on the PA 
board and it is doing the same to THREE supplies, my 2 PS125 and my PS85. 
All 3 supplies are not going to have the same internal short or temp 
elevation to shut down. Does the PRO III shut down with PA increased temp if 
inadequate cooling? The rig has been in SAME place for 2 years with problem 
and with same PS125. I know there is over current protection to shut down 
the PRO in the PSU but is there also an overcurrent protection INSIDE the 
PRO too?  I am not aware of one.  Guess what I am saying is (aside from the 
PSU current protection) is the PRO itself protected for too much current OR 
too much heat?
   Thanks Tony.
San K5YY

-----Original Message----- 
From: Tony Hwang
Sent: Monday, July 02, 2012 9:24 PM
To: ICOM Reflector
Subject: Re: [ICOM] my PRO III shut down problem

Hi,
overloading due to several different reason
such as over temp. over current, short, etc.

Have you tried with RF drive to minimum to see symptom changes?  Did you
try with dummy load w/o antenna?

Did you watch the SWR reading?
Is the PSU going into crow-bar condition? Watch the Ic reading on the
meter when it happens. If you can keep
the radio and/or PSU in a freezer and try it when it is cold.
GL es 73,
VE6CGX
Tony