A PSM-6 Ohms Demo setup. This setup demonstrates the accuracy you can expect from the re-engineered resistance measurement circuitry. This resistor has been certified at 991.5 ohms - exactly. The meter is set on the Ohms function and on the ohms X 100 range. It is 68 degrees F in the shop. You can see the needle on the meter is directly above the "10" on the ohms scale - 1000 ohms. This meter has an accuracy at this level of .085%. The calibration standard is 3%. This is typical of the accuracy you can expect across the entire range. MUCH better than the specifications require!
Just how accurate can a 40+ year old meter be?
The PSM-6 is on the 50 VDC Range - It is at the mid point exactly.
The 199 ScopeMeter is delighted to share the same bench space!
On this particular Sunday afternoon in December 2011 this it what you would find here on the bench:
Tektronix CMC251 1.3 GHz Frequency Counter
BK Precision 4011A 5MHz Function Generator
Fluke 893A Differential Voltmeter
Fluke 8800A/AA 5.5 Digit Digtial Multimeter
Energy Concepts 20600E AC/DC Bench Power Supply
Tektronix 214 Storage Oscilloscope
Fluke 515A Portable Calibrator
Fluke 289 True RMS Multimeter
PSM-6B Military Multimeter
Sencore Super Cricket Transistor/FET Tester
Not in the picture
Tektronix 475 Oscilloscope with DM 44 Multimeter
Tektronix 305 DMM Oscilloscope
Flute 88V Digital Multimeter
Fluke 412B High Voltage Power Supply
Fluke 8042A Bench Multimeter
You can buy with confidence! All this equipment is extremely accurate or it wouldn't be here. I can achieve accuracy far in excess of the DOD specifications for all military multimeters sold on this site.
This is the testing bench upgraded to include Fluke calibrated test equipment and high current variable AC/DC power supplies .
About every other PSM-6 and almost every PSM-37 will fail to pass some part of the testing sequence. If so, troubleshooting to the component level occurs here - then it's back to the disassembly bench for part replacement, inspection and QC.
I was taught to solder by the Air Force then NASA improved on the technique tremendously!
In fact I am still called on to perform critical soldering techniques at a former NASA facility.
This is the full scale 50VAC test required to balance the internal rectifier to the metering components. This is one of the more important adjustments that must be accomplished before the meter can be certified to ship.
This is a picture of my Fluke bench meter and a PSM-6 under test.
"They" say a picture is worth a thousand words... This one is worth 20,056 millivolts! Notice that the PSM-6 is reading exactly 20 VDC!