PSR-2 Alarm, Chemical Agent, Automatic

Brooke Clarke, N6GCE 2004

PSR-2 Front w/sensor


The military has a number of Chemical Alarms and the PSR-2 is one of them.  They are available on the surplus market.  Can detect falling liquid nerve and blister agents. 

Prime Power


This is a AUX PWR connector in the upper left of the front panel that allow an external puwer source to be used.  It has 8 recessed small pins and 4 larger recessed pins.  The mating plug would have a total of 12 sockets and the shell diameter that fits into the AUX PWR receptacle would be a little less than 0.81" diameter.  The AUX PWR cap is marked: MS27502B115C.
Mike Murphy has the mating connector as a MS 27467T15B9-7S

Military Chemical Agent Alarm Power Supply model ABCA-M10 probably will not work with the PSR-10. I say this becasue there is a sticker on the front saying "Danger High Voltage" and the PSR-2 runs on "12 Volts".

Internal Battery

On the bottom of the PSR-2 there is a battery compartment that's accessed by means of 6 each 1/4 turn captive fastners.
The batery compartment is designed to hold a BA-5588 battery but my 68BA Battery Adapter will work after filing a small radius on the two lower corners.


PSR-2 Sensor
              Close Up 16 MB imageThe sensor is a plastic disk about 5.5" in diameter and 1/8" thick.  It has a 1/8" diameter hole in the center and another one at a radius of 2.47".  These holes are connected to each end of a single spiral made by machining a groove in the disk, very much like would be in a 45 PRM record, except wider and deeper, and filling the grove with conducting particles and chemicals.  The turn to turn pitch of the spiral is about 0.010" and the groove itself is about 0.005" wide.

Marking on the back:
REV 5   LOT 92344
SERNO.   12968

I've read that the sensor does not react to Jet exhaust or JP-4 fuel droplets, but does alarm when certain chemical agent aerosols (not gases) fall into the grove.  My PSR-2 came with the sensor installed and I don't know how long it has been out of the wrapping. so the following measurements may or may not mean anything.  I think the sensor has a useful life of about 30 days once it's removed form the wrapper. Resistnace 1.7 Meg Ohm, Capacitance 0.86 uF, both measured with a Fluke 87 DMM.


Mike Murphy - sells the PSR-2 and sensors
eBay has them now and then

Back to Brooke's Products for Sale, Batteries, Survival Equipment, Military Information, Home page

This is the [an error occurred while processing this directive] time this page has been accessed since since 20 Jan 2004.