Tube Testers and Test Equipment
Quality Test Instruments for Technicians or Hobbyists
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EMC 206 Tube Tester – $199 free ship USA
EMC 206 is a very rare model of tube tester, and not much documentation exists. This unit is in excellent cosmetic condition in my opinion — really nice real hardwood case. I installed new feet on both sit-down sides.
This model was marketed as a mutual conductance tester, though it is not a true mutual conductance test circuit. To give you a summary, this model uses AC voltages on the plate and screen, and AC and DC on the grid. The DC bias is variable and taken from the DC bias pot; the dc bias was rectified by the 6H6 tube inside. The line control is also rectified by the 6H6 tube. Thus, it is a unique test circuit, different from a “dynamic conductance” circuit (such as a Jackson or Eico 667) because it applies a DC potential to the grid, but not a true mutual conductance test circuit such as a Hickok or B&K (which applies pulsating DC voltages to the plate and screen). The sensitivity control is only applicable to diode-rectifier testing, or amp tube testing when using the red-green indicating scale.
As noted, the only documentation that exists is a small instruction manual, a copy of which is included. No schematics or calibration procedure are known to exist, at least not to my knowledge.
As tested, the shorts sensitivity is rather sensitive, approx 1.7 megohms. The gas test is extremely sensitive (in fact, a degree of common sense and comparison with other known-good tubes will be necessary for the gas test.) Photos show test results from 5U4GB and 6L6G using the good-bad scale. Test results for these tubes are more than reasonable, as both tubes are well-known to me.
Limited servicing was done. I replaced a number of out-of-spec resistors and cleaned all of the controls. The unit is not “calibrated” because no calibration documentation exists, and no representation regarding performance is being made.
This tester has a basic roll chart, so it would be best considered as a tester of “antique tubes.” It would be a good affordable compliment to a newer-style tester — such as Mighty Mite, B&K, or similar — because you would be able to test the popular antique tubes.
Signal Corp I-177-B tube tester, manufactured by Simpson, with rare MX-949A/U socket adapter kit, nicest I-177B and MX-949A that I have ever seen or owned, tester serviced & calibrated, $799 free ship USA.
(This combo sells as a pair; I will not sell the MX-949A/U separately.)
Here is the nicest I-177B and MX-949A/U that I have ever encountered (either myself or sent to me for repair by a customer), this combo has been a part of my personal collection for close to 15 years, tester made by Simpson. The Simpson-manufactured units are extremely high quality and well laid-out inside. I am including the very rare MX-949A/U socket adapter kit. Both items are in really outstanding condition.
I have serviced & calibrated the Signal Corp I-177-B mutual conductance tube tester. Servicing consisted of replacing the #83 tube with my solid-state fused upgrade, checking the 5Y3GT tube for excellent balance with my oscilloscope, cleaning all pots, switches, controls with Deoxit. Socket pins cleaned and shine very close to when new. Many original carbon comp resistors were replaced with fresh modern carbon-film or metal-film 5% or better. Recapped. Brand new grounded line cord installed and with new rubber eyelet grommet. Line calibration performed. Calibration voltages checked & set for accuracy (150v plate 1000 ohms/v, 130v screen 1000 ohms/v, accurate bias voltage checked at several positions of the bias pot, signal voltage 5.0 vac), overall calibration checked against my calibration tubes. Diode/Rectifier/0Z4 test functions checked for accuracy. Gas test checked for accuracy. Shorts test checked for proper working condition. General cleaning inside & out.
Includes original tube data setup book. No other paperwork included, but tester instruction manual and additional supplements can be downloaded or forwarded via email PDF.
The I-177 series is a quality mutual conductance tube tester, Hickok-style circuit, and designed for testing older tubes, pre 9-pin-miniature. The MX-949A socket kit adds a lot of flexibility to testing (such as testing 9-pin-miniature and septar base tubes), but honestly it is somewhat of a pain-in-the-butt to use the socket adapter and therefore should be considered as an extra that you would use on a very rare occasion. It does come in handy if you want to test rare transmitting septar-base tubes on the rare occasion that you need to. Overall, I highly recommend the I-177 series as being great for antique radio servicing or tube collectors that require setup data for oddball old military tubes.
When considering to buy an I-177 tester, even though the socket adapter kit is included, I can tell you that the I-177 series is not ideal for someone who only wants to own a single tube tester, because testing 9-pin-miniature or newer tubes is slow and cumbersome because you need to use the MX-949A socket adapter kit. In a nutshell — if you want a top quality vintage military tester for testing primarily the old basing tubes, then this is an awesome choice. It does a great job of testing the old 4-pin, 5-pin, 6-pin, 7-pin-large, etc… types of tubes because you do not need to use the socket adapter kit. Therefore, if you need to test 9-pin-miniature tubes more than rarely, you really should look for a different tester.
What many pro’s do — they will pair this I-177B + MX949A combo with a newer tester, such as a Sencore Mighty Mite or B&K, which provides them the capability to test the overwhelming majority of USA tubes ever made.
Photos below show the outstanding condition of the I-177B tester and the MX-949A/U socket adapter kit. Photo also shows accurate testing of my 6L6 calibration tube (not included).
Yes, you are getting 2 newly assembled probes with this nice Eico 147A signal tracer. This is an excellent model, works well for both Audio signal tracing and RF tracing.
Here is a nice Eico signal tracer for your repair shop. The uses to which you can use a signal tracer are almost endless. Awesome instrument for audio repairs and radio repairs.
- many new capacitors installed
- new input jacks installed (RCA style, which allows much easier sourcing of probe cables for future needs)
- Murata X1Y2 class RF suppression capacitor installed on AC line
- newly assembled Audio probe
- newly assembled RF probe, and yes my RF probe works great
- 3-wire grounded line cord. Better inherent safety –but– you will need to use an isolation transformer to power the D.U.T (device under test). That is proper safety protocol anyway, so if you are not using an isolation transformer on ALL of your repairs, you will want to start doing so.
- overall nice condition (front panel and metal case)
- good magic eye tube
- copy of instructions included
powerful 45-AMP Filament transformer 6v – $39 free ship USA
Here is a whopper for your tube projects! A massive 45-amp filament transformer. Nominal input 115vac, nominal output 6.5vac @ 45A. Want to build a massive tube warmer/heater? Now is your chance. With this transformer, you can power the filaments of almost *50* (yes, fifty…) 6L6 tubes at the same time! Size: approx 4L x 3.25W x 4.5H inches.