[Milsurplus] I-177B tube tester

[John Hutchins]

Group

"Calibrating" my I-177B tube tester .
The tube tester came out after spending  23 years in the garage.  I 
purchased the tester in 1975 in San Antonio at a salvage yard for 
$5.00.  The unit at the time had a tag that I tossed aside.  Wish I had 
kept the tag for historical reasons.  The unit was partially rewired 
most likely as practice for a Air Force tech. training exercise. 
I had noticed that tubes I had not touched since 1985 were measuring 
lower than the taped markings on their boxes.  Acquired full manual and 
schematic from a list member, Robert.   This was a great Sunday 
project.  Six, 6 resistors were replaced with Carbon Films purchased 
from Mouser.  Checked 3 510pF mica caps they were still dead nuts!  The 
bulk of the resistors were wire wound and were measuring as marked.   I 
remembered that I cross checked a hand full of various tubes comparing 
readings between my I-177 and a "radio shack" tube tester;  it was close 
enough at the time. Ran some of my old marked tubes and measurements 
were a little better than my old readings.  I expected this since I just 
used the tester as is for years - good tube bad tube.

Knowing what I know about how fragile and scarce some of the equipment 
is,  I am surprised I never burned up the tester before acquiring the 
OPS/Service Manual !  Thanks to Robert;  it does help to know the 
facts.  I never knew what the tester was capable of, I do now.

Later:
Hutch