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Up for offers today, is a nice working example of aWeston Model 789 Type 3 Proportional Mutual Conductance Tube Tester. As you can see from the photos, the case is in need of some paint, but there are no dents or dings. The tester does work, and appears to be all original. Photo number 5 shows the line adjust setting centered correctly, and photo number 6 shows a known good 53 tube under test, reading about 2100 micromhos (Gm). It does take about 30-60 seconds to obtain the Gm reading. The pilot light (power on/off) and overload indicator do illuminate, however, I did not see the short indicator lamp illuminate intermittently when going through the shorts test. No further testing was done on this unit. The inside of the tester looks clean, and the test lead directly above the meter appears to be missing an end connector.
The plate and grid clips are present along with an 8-pin tube extender/socket and 3 sheets of various tube data. (The manual for a Type 2 tester can be found on the BAMA site, and can be used with this unit). Please note, that even though this tester is working in its present state, it is original, and will need a proper restoration and calibration at some point. However, these particular models aren\'t all that common and would make a good addition to your collection or as an in-service tester once restored.
Please ask any and all questions and I will respond promptly. Shipping will be via FEDEX Ground to anywhere in the US. If you live outside of the US and wish to offer, you may do so, but only through \'s Global Shipping Program. Good luck and thanks for looking, and for your offers. offerding starts at $9.99 with !
