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These are restored vintage Tube Testers manufactured by the Precision Apparatus
Corporation from the1940s to the 1960s. I have restored quite
a few Precision Tube testers, and I am quite impressed with the craftsmanship and
quality in these vintage units. I really like the old wood cases.
These are all Emission type Tube Testers. Precision's "Electronamic"
design in some models of Tube Testers was an attempt to improve on the basic Emission
tube testing principle.
Some of the models included VOM functionality. Precision called
this "Set Analyzing". I try the best I can to restore the VOM
functions in these old testers. I have come up with modern replacement
battery systems so the Ohm Meter functionality will work properly.
It is amazing that the VOM functionality in these old testers is still quite accurate
after all these years.
Most of the testers include battery testing functionality. Batteries
are tested with a load resistor and will show the condition of a battery under load.
I generally do not concern myself with this functionality.
The value of having the battery testing feature is not worth the cost and effort
to troubleshoot and repair. Most of the time it works properly
anyway.
Some of my tube testers are for sale. These units include written
manuals and updated tube test data. They have a one-year warranty
that does not include burning out of the meter movement. Tube
tester meter movements are very delicate and can be burned out very easily by testing
a shorted tube, or from improper test settings. I find the most
common functional failure with these old testers is meter movement burnout.
I will also purchase any Precision Tube tester or parts you may have.
Email me at vintageradio@swl-remotes.com
with what you have and I will make an offer. Let me know if the
unit works and what parts are missing. Include a picture so I
can evaluate the unit.
All these tube testers are restored.
Restoring includes:
- Clean all switches and controls with contact cleaner.
- Replace any missing, broken, or incorrect buttons and knobs.
- Replace capacitors.
- Replace out of spec resistors - especially in the tube testing circuitry.
- Replace power cord.
- Replace Elmenco fused plug if missing.
- Verify/replace fuses for proper protection.
- Test and replace neon shorts indicator lamp if necessary.
- Restoration of VOM functionality if possible. I do not repair
or re-calibrate the VOM features. This functionality is not worth
the cost or effort to restore. Usually a new battery will get the Ohms functionality
working.
- Replacement of bad meter movements if possible. Many of these
testers have modern meter movement equivalents. This is expensive
and I try not to do it unless the tester is in really good shape and is worth
the expense. Replacement of a meter movement in a tester with
VOM functionality will change the circuitry enough so the VOM features will no longer
be accurate. Tube testing can be recalibrated.
- Calibration using a 6L6 tube of known emission.
- Verify roll chart is working. I don't try to update the roll
chart. I have printed documentation
for all these testers for older and newer tubes that I use when testing tubes.
I don't want to take the time to position the roll chart when I need to test
a tube, and I'd prefer not to damage the chart from over use.
- Refinish wood cabinets. Tube testers were used by radio and TV
Repair shops and saw a lot of use. The wood cabinet finishes
are all badly worn, and many have damage to the wood itself.
- Recondition all cabinet hardware. The cabinet hardware is cleaned
and oiled so it will work properly.
- Replace rubber feet.
- Replace handle if missing or broken.
Precision Tube Tester Manuals and Data Charts can be downloaded at
Chris's Old Radios.
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This is a restored Precision 912 Tube Tester. The case is actually in
pretty good shape. with no damage and only minor scratches.
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Restored Precision 912 Tube Tester
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Refinished Precision 912 Case
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This tester includes “Set Analyzing” functionality. I adapted a
new GE NE-30 neon shorts indicator bulb. This is an equivalent neon bulb,
but the base is much larger. I had to build a socket for the new bulb.
Unless you look under the deck, you'd never know that the neon bulb is not original.
I built a replacement 4.5 volt battery for the ohms testing using three AAA batteries.
It works just fine, but ohms testing is not accurate.
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Restored Precision 920 Tube Tester
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Refinished Precision 920 Case
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This is a really nice tube tester, The case is in excellent shape. The
case hardware (hinges and latches) is a little rough. This tester includes
“Set Analyzing” functionality that actually works. I made a replacement battery
for the Ohm meter funtctionaliy using a "C' cell battery and it works great.
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Restored Precision 954 Tube Tester
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Refinished Precision 954 Case
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This is a pristine example of a Precision 612 tube tester. The
Precision 612 is a basic Cathode Emissions tester with battery testing functionality.
It does not have any VOM functions. Calibration was spot
on and did not have to be changed.
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Restored Precision 612 Tube Tester
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Refinished Precision 612 Case
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This is a very nice older model 10-12. It is in excellent condition.
The meter movement was replaced with a newer meter movement. The
meter indicator is a pointer, rather than a line indicator. The
dial face attached with the same mounting holes. This kept the
unit as original as possible. I even have the original warranty
card for this tester.
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Restored Precision 10-12 Tube Tester
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Refinished Precision 10-12 Case
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This is a very nice newer model 10-12. The serial number has
a “D” prefix character, and you can see the difference in the knobs used on the
deck. The electronics appear to be the same as the older style
10-12s.
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Restored Precision 10-12 Tube Tester
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Refinished Precision 10-12 Case
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Precision 10-xx Solid State Prototype?
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Does anyone know anything about this tube tester?
I believe it is a prototype Precision 10-xx that never saw production.
The meter is from a 10-12 tester. The power supply uses
a top hat solid-state rectifier instead of a #80 tube. I can
test tubes on this unit using the test data from a 10-12 tube tester.
The buttons for “W”, “X”, “Y”, and “Z” are individually pushed to make the connections
to the tube rather than the lever switches like on the 10-12.
There is a knob that is pulled to clear the pressed buttons.
There is a “Gas” pushbutton that is not connected. There must
have been plans for a gas test in this tube tester. A compactron
tube socket has been added.
I would appreciate any information that anyone has about this tester.
Email me at vintageradio@swl-remotes.com
if you know anything about it.
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Precision 10-xx Prototype Deck
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Precision 10-xx Prototype Back
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Precision 10-xx Solid State Prototype
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This is my "go to" tube tester. The Hickok 750 is a Mutual Conductance tube
tester. Mutual Conductance tube testers are the best for true vacuum tube
performance. When matching tubes, this is the best type of tester to use.
The meter movement on this tester has been replaced. The original meter movement
developed a mechanical problem. The needle came unglued from the movement
coil. A quick fix got it going for the short term, but a new replacement movement
was installed.
This tube tester is in pretty good shape. A lot of the old Hickok tube testers
were work horses and were used daily. This resulted in a lot of wear on most
of them. The case on this particular unit is not too badly beat up.
There are a few nicks and scratches; overall the tester is in good condition.
There is no calibration procedure available for the 750, but several other
models of Hickok tube testers are very similar and the calibration procedure
can be used from these other testers. I calibrated this tube tester using
what information was available. The shorts testing circuitry was pretty far
off. Most every tube I tested before calibration showed a short. It
now works properly following the calibration.
What I particularly like about this tester is that I can check for overall tube
quality and also check Mutual Conductance.
I have found a lot of tubes that will check good on an emission tester will test
bad on the 750.
Hickok tube testers command a premium price these days, but overall this 750 is
a nice tube tester and well worth the investment.
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Hickok 750 Tube Tester Deck
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Hickok 750 Tube Tester Meter Movement
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I picked up this tube tester as a trade for refurbishing an amplifier and a tuner.
The history of this tube tester is that it was used by P & G (Proctor and Gamble)
and then surplused out some years ago. The case shows some wear,
but the deck and electronics appear to be in excellent shape.
The original power cord is still in excellent condition. I checked the calibration
and it was spot on and didn’t require any adjustments. This is
a very nice tube tester that doesn’t appear to have seen much use.
The 6000A is a compact unit that tests the newer tubes like Compactrons and does
not test the older 4, 5, and 7 pin tubes. I use this tube tester as my
everyday tester for newer style tubes.
I especially like the shorts indicators. With a quick glance you
can see if there are any shorts before testing the tube for quality.
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Hickok 6000A Tube Tester
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Hickok 6000A Tube Tester
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