Hi,

What is the difference between the USM/118, USM/118A and USM/11B?
Are there any cosmetic differences?
How do you tell them apart?
Which tester should I get and is there a Serial # series I should try and avoid?

Thanks,
Tony

[Ferd Burfill]

Originally Posted by Tony Hardee

Hi,

What is the difference between the USM/118, USM/118A and USM/11B?
Are there any cosmetic differences?
How do you tell them apart?
Which tester should I get and is there a Serial # series I should try and avoid?

Thanks,
Tony

Tony
according to Aaron,
"AN/USM-118A vs AN/USM-118B
The major difference is a two-transistor meter protection circuit in the 'B'. All of the units I've ever seen (with the exception of one) have been B's.

It is virtually impossible to tell them apart by looking at the identification plate or stenciled identification. The tester proper is usually labeled "TS-1479/USM118A" no matter what it is. Look for "part of AN/USM-118B test set" on the ID plate. In fact, all of the parts (cards, cells, tester, etc) are labeled something-NNNN/USM118A. "

Which is as clear as it gets as far as I can tell. Here's Aaron's web site:
http://www.spiritone.com/~nabil/hickok/

There are several other key resources;
http://tubesontheweb.com/matic.htm that discusses both the standard unit and the computerized modifications that Phil offers:

http://www.theoldradiofixerupperguy....atic_data.html where Don has some useful info on the commercial cardmatics (Hickok 123A) but I've never gotten any answer to emails;

http://bellsouthpwp.net/p/a/padgett46/hickok.htm which is the right address for Padgett's page, most of the older links you'll find are no good;

http://bama.edebris.com/manuals/hickok/ the BAMA boatanchor page for the KS-15874L2, the WE version of the 118B, and http://bama.sbc.edu/ the homepage where you can surf around and find thge USM stuff under the military category I think;

http://www.hificlassifieds.com/tubet...k_download.htm, Nolan's site that has non-USM-118 but useful info;

http://64.233.167.104/search?q=cache...lnk&cd=1&gl=us another hickok resource, where info on the adapters, the CA-4 in particular is found;

http://www.electronicfied.com/sci.el...date_3091.html a useful thread I found with some maint/cal info.

That should get you started, If you are fortunate enough to find one in good condition, with plenty of cards, and under $1000 you'll have a real treasure, one of the 2 or 3 recognized benchmark testers around. Let me know how you make out.