On 23/2/19 3:18 pm, Jeff Liebermann wrote:
On Fri, 22 Feb 2019 17:51:18 -0800 (PST), wrote:

Hi. I have a IFR1600 service monitor that was working perfectly but now will not power on. I suspect that the power supply module has a stuck relay as last time it worked it would not turn off and I unplugged it to get it to turn off. Anyone have a schematic of the power supply and power up circuit? Or if you have run into this problem please feel free to offer suggestions. Thanks for your time and help.

IFR power supplies seem to be a problem. I have an IFR-1500, also
with a power supply problem:
http://www.learnbydestroying.com/jeffl/IFR-1500%20Power%20Supply%20Repair/IFR-1500%20power%20supply%20repair.html
The repair didn't last and it died again after about 2 years. I then
replaced every semiconductor and capacitor in the AC power supply
section trying to revive the PS but no luck. I'm now looking into a
replacement brick power supply for AC only operation because I don't
need 12V operation. Amazingly, the original PS still runs on 12V,
which is the way I currently run it. You might want to check if yours
also runs on 12V.

You should be able to find the necessary documentation he
http://www.repeater-builder.com/test-equipment/aeroflex/aeroflex-index.html

If you want to buy a power supply or have yours repaired:
http://www.siliconinvestigations.com/ifrrep/ifr1600/ifr1600.htm

Good luck and please let me know if you find anything in your power
supply. I suspect the IFR-1600 might be similar to the IFR-1500 power
supply design.


I have a COM-120A which has an external power supply bolted to the back.

It was faulty already when I received it (probably baseband module
needing capacitors) but while in storage awaiting attention the CPU
board got tired also and the video went strange, followed by it not
booting up at all. Although the RF path is probably ok enough, these had
an 80186 that was woefully underpowered - the -B and -C introduced more
powerful CPUs - so now I wonder if it's even worth attempting to
resurrect it - though an acquaintance nearby has one on which he
replaced the video board and made it go again. Just too much work needed
for too little result.

Basically I can only ask folk to "vote with their feet" and stay away
from manufacturers that don't release full service documentation
including schematics. IFR was a bad example.

Clifford Heath.