Hickok Tube tester  532 reactivated from 1945 . ::::::  by me... K5jxh        
Or how to have fun fooling about with 1945 gear.  (hint; avoid it)
Avoid near useless Grid  Emission boxes,  and  try to stay after year 1970.


My better tube tester is here my great (B&K 747B) {mint 1975}  See how to get rid of gas?
Rule#1 is do not buy old  grid emission testers. testers. They are mostly useless. (buy only Gm testers as  true measured Transconductance testing Siemens =   Mho (℧))  Look for MicroMho's on meter face.
Joykiller 1: bad switches not sold now, and bad transformer or meter, and last custom made BIOS POT.'s  not sold now at all. now  unobtainium
The most hard part of getting any good accuracy from the testers is that 1 dial called (English/BIAS) even the most small bias change changes the gain of the tube vastly.
There are no  true absolutes here (ball park yes)  The tubes sold new vary in Gm geatly (even at 1 bias) as does the tester vary. (they can even fight each other)
There are 2 kinds of GM testers , a huge box of rotary switches (if 1 bad are impossible to find) or a box with  47 sockets like Dyna-quick 707.(shops loved this for the fastest  tests possible and more PROFITS)
I cover below the  factory modification (#49 lamp overload preventer) and 2 more lethal cure mods and a new calibration pot added R6a.
,
GM is now called Transconductance / Siemens.

It's not pretty but  ugly comes dirt cheap.
This one is a first  model 532:  (not even near as good as the newer models of Hickok like 600 series or 6000a)
 
The Bias/English pot I upgraded due to its death.   (best is not buy this) I did just for fun.



Back 75year ago they had no way to build in  precision GM (transconductance) standards inside the unit , for manual or automatic calibration.  
Nor a way to make the tester, super intrinsically accurate. (like todays laser trimmed,  DAC's do, digital to analog.)
To get good GM readings the bias voltages must be correct. (one why to quickly check this is with Bogey test tubes)
The method that was used, was to use Bogey Tubes,  a tube with a stamped on the side GM rating.
This BIAS inside your tester is far from being  accurate, so the GM will not be accurate.
Nor did they feel using DC Voltage regulators to keep DC a solid line at all AC line voltages,  that is a big big error there but back then , the had OA2 regulator tubes, that could do this job.
We will attempt to make that better below by calibrating the English BIOS PoT using my Bogey tube.  Getting this scale to read correctly is not easy.


KNOBS:  (wafer switches and more)   First make sure the rotory switches are not broken inside or contacts mangled after 75years.

See these Selector switches, see the numbers?in dial aperture?,  the numbers seen there are tube pins Filaments grid to Suppressor.
So case in point 6V6 tables show(JR5347-2 tells you that grid pin 5, plate 3,screen 4, cathode 7, Supressor is 2)
 Knowing this fact one can add tubes not listed, if you have a calibrated tube sample.

The tester is simple in theory for just  1 tube, but in practice the wafer wiring is insanely complex and so many tube sockets used then and more later.
All switch contacts there must be good and wired right.   (most HAMS only need, 7/9pin minture tubes , OCTAL (std) and compactron tube support, 4,5/6 pins are 1920 to 1930 relics.
  .
 This 9pin NOVAL socket was added long ago is dead(see factory service sheets), and makes me suspicious (done wrong?)   but I do not care  about this socket  at all. ( skipped)

See my my  slide show!
The top plate was treated with 10% Phosphoric acid, this halts rust , removes it and converts what can't be seen to a primer like compound , called iron-phosphate (a barrier to further rust).
Fixes and Mod.'s
1: Bad BIAS pot, cured.

AC power is not safe here:

1945 illegal now , (NECA/NEC) with no ground  from AC 3rd pin to top metal lid inviting 200vdc landing on lid and you not happen much.
In fact,  is in  Stark contradiction to safety. 225vdc is not safe to touch ,  for sure at these currents., and the words " halcyon days of tube technology"
So now mine has real power 3  wire  cable modification upgrade #1. A new AC line cable off a old tool. (free fix)
See related killer#2 here.
Next is the ugly fact, that there are no wire colors   shown in the schematic, (dang me)
Last is  there are no transformer pin's ID's shown in the schematic . (there is a transformer page I annotated it.)
My transformer is good and so is the meter. (Bias POT is a wreck) So I cloned it. (using industry standard parts, far better than the original)
I now have tested many tubes and it works, and my calibration pot added makes it plenty accurate, ( not at NIST.GOV standards at all)

Do not read this , this is how Calibration TUBES were made back in the day.
Gm  or Transconductance,
  I will call it uMho still, after all , our radios all have USA TUBES and has a matching RCA tube manual and others, all stated in Mho's. ( micro mho's not Siemens)
Both the tubes and testers were not accurate then.
Tube variances then from the top 10 tube makers the GM new in the box tube varies as much as (+/-)40%  that was the spec.  citation: (per page  64  by R.Tomer)
Most gear worth salt assumes the Gain is on the low end, new tubes, (natural variation)
These testers are a blunt instrument too, as were the actual tubes, it is not a laboratory class instrument, not at all, nor is it the tester (Hickok) makers intent.
(It was a simple tool to service an old TV or old radio) Finds dead, or gassy or very weak tubes, for sure, and very useful.
No 2 Radio's T.V's (television) or gear (ham) PA Amps HiFI, use the same BIAS on the tube.  (grids and plate)  That is fact and the tester can not be clairvoyant and guess that.
Not only that a test that did say test 3 points on the tube makers BIAS curves that would be a very expensive tester in deed, and was already super high then. $500 is $7000 today (2020) inflation.
This tool does not run a full transconductance scan at all, in fact , it picks one point on the spec, and tests only that.
The plate voltage is limited too.   It can NOT test a 6L6GT tube at 500vdc plate voltage, as many in fact or used in powerful audio amplifiers. (fully "Pentode" tested)
The 6L6 by the way is very commonly used BOGEY tube then and now.
end bogey:

The GOOD Features:   (Do not read this it is about GM and how it varies greatly usage (bias used) and from tube to tube.)
The best feature of any tester or Hickok is the Dynamic mutual conductance test,   and is an amplifier, is the  small change of grid voltage resulting a large change in plate current.) 
Mutual conductance today is called TRANSCONDUCTANCE.
Most if not all tube testers test only at one point in the family of curves, note the Gm curve is not linear, note too that some tubes have radical curves, or remote cut off or other odd qualities.
That means if testing at a radial point in the Gm curve any tester inaccuracy will have  a profound Gm error reported.   (the bias errors are bad on many testers, both Grid bias and signal and plate voltage.
If you just look at the testers schematic for 1 second what do you see missing (BIAS regulators of any kind or so crude as to be pathetic in todays context)
No 2 testers made test the tube at the same BIAS/ load, so Gm on 1 Bogey tube from tester to tester (even top quality Gm tester) will vary greatly, but all will be in the GREEN GOOD BAND.

u = Voltage amplification.  (V input over V out) a.ka. Gain or Voltage gain.  (  plate volts/ grid volts = u)
Gm - Transconductance. (in Siemens) or stated as  mA/V.   (means plate mA /  grid signal Volts) 
Rp  = Plate resistance [load]( that tube acting like dynamic variable resistor , not much different from a transistors gain)   and  Rp = u / Gm
 
and  gm = u /  rp

Many testers only test a Pentode  Tube as simple wired that way Triode.
A typical tester will only test this tube at 200vdc. never seeing  300mA plate current ever.  It will never be tested at full load, full power.
Hint some tubes fail at full power.
But sure beats a kick in the head no?  I can find bad and weak tubes easy. Not perfect tubes. This tube is common for being used as BOGEY tube.
Used for many things this tube,  Public Address audio amps. , HighFI amp, (even Stereo amps) and guitar amps.  (RF amps up to 10 MHz.) The 6AQ5 is good for 54 MHz and 11 Watts Output.
(and for 47 watts in push-pull amp of power) KT66  close EuroCusine.
6000 Siemens = 6000 Mho (℧) par for this tube. 
(old books 1950s)  CPS= Hz, Kcps  = KHz.  , below E means voltage and C1 means control grid 1 voltage (or VG1 =EC1 new to old) Ef= filament 6.3vac
S; 1 siemens = 1 ampere per volt replaced the old unit of conductance, having the same definition, the mho (ohm spelled backwards), symbol, .
The "transconductance testers"usually measure. A small AC voltage is placed on the grid#1 of an otherwise appropriately biased tube, and the AC voltage on the plate is displayed, perhaps divided by the (fixed) AC gridvoltage, giving an approximation to mu.



Grid #1 means Ec1 or Vg1


Click here to see simulator below.


In General:

If the tested tube reads in the green scale or is in the ball park of expected GM of 6000,  say you read 5000 that is ok. (some new tubes do just that)
Just because one tester dial reads "umho's" does not mean it's any better at all.  My B&K 747 , reads in percentage of uMho's and is just as accurate as my Hickok. (In fact match so close, it's amazing.)

Warning some tube testers can damage tubes with when doing shorts tests. (1volt tubes , with tight clearances deep inside the tube?)
Do not let your tester use huge amounts of grid current ,or  the grid can be damaged easy, or damage the cathode.

KT88 Load line, online calculator
makes understanding tube performance based on all pin voltages and loads, (and mu changes)
Va = voltage anode plate, Ia = current anode.

The POINT OF ALL THE ABOVE is to show that , no 2 testers made use the  same BIAS voltages, so Siemens are not the same.
It also shows that both the tubes vary by batches (lots) for Siemens actual (Gm) widly
and that the tube testers do not have good accuracy at all for sure,  using old testers 1945.
The tester is just  ball park device.  (seems good or seems bad or weak or dead, or gassy or shorted elements )



end theory ....


Matching UPGRADES to this tester: (rare)  The Compactron upgrade.  (my Heathkit ham receiver uses them)
One  up grade, is this  from the  maker,   the charts are available even  for the 532.  CA-4  and newer testers.
For Compactron's (3 tubes in one glass bulb!) I have  6AS11 radio. But refuse to buy this ,just for one tube. (grin)  One guy made 1 tube Compactron radio using a 12AE10. (thanks DAVID !)
So expensive now, I bought a 2nd tube tester that does these tubes.

Inspections and tests 101:  (I use electronic Jargon, after all it is Electronic here, see those TUBES?)

The show stoppers would be: 
  1. Dead meter. (or sticks)  {a sticking meter may be cured, if you look inside it, and find iron dust (or filings) inside, (the magnet loves to find ferris dust, and jam the coil) use tweezers to remove said dust}
  2. A Dead transformer (burned up or open / shorted) {not cheap to rewind one}
  3. Broken any of the 9 rotary wafer selector switches (Phenolic resin wafers damaged), near impossible to find matching switches today.  ( buy tester that has the largest number of sockets and less switches is a best idea)
  4. A Dead burned up BIAS pot (3k ohms 1w) I got a 4watt for $10 , (original is not sold on earth) look below for my reversed engineered data on this pot. 
  5. Last and very hard to detect, is some dweeb, wired up all those wafers switches wrong, oops... that be hard to fix. (buy 2 testers and make one good one?) (the wire colors are not documented at all)


My BIAS POT Story,  (best is never have this problem, or avoid any old tester with this POT dead)
DO NOT Read my horror below it  is only me using the wrong POT and then making tables to convert old dial readings to new reading on the wrong POT , not fun for most folks to do or try.
I did this just for kicks to see it can be done.
Power and POT.'s; (POT = Potentiometer, or rotary variable resistor)
This Original POT is a custom Hickok proprietary design with undocumented logarithmic taper and more. (a calibrate bar is hidden inside)
The first testers had a DESIGN flaw, no protection from shorted tubes, to protect  my bias pot. (see fix below)
but...
Then in 1951, they wrote and service bulletin to correct this and added #49 lamp fixes this flaw. (so could a 100mA fuse)  The place it goes , is on the center pot lug, in series with it. Mouser.com has the lamp and holder.
My pot burned up long ago. (now useless) making tester useless:
What I did below is and ugly  hack just to see if I could make it work:
The BIAS pot I'm now using is rated 4watts, but that is only when the dial is at 3000 ohms.  (here is a more a much better pot ,note how easy air can flow here...)
Note too that the old  pot casing, below (bad design) acts as a sealed cup and holds heat inside here! and is very poor grade plastic ,  it likes to burn.
One more pot example , there are much better pots .
There are many kinds pot's, carbon  , Cermet and WW, wire wound, as clearly seen below, carbon POTS are 1/4w  mostly and totally  useless here (burn up it will).  (but great or say a radio tone/volume control)

The stock pot was 1watt and pathetic, I'm later adding with the factory lamp mod. , a solid state fuse here,  (more later but...Bourns, makes these  ) Specifically this. at 72 cents!
I am told today, that the T-105 service bulletin , (missing this revision in my rig here) adds a #49 lamp (2v@60mA) to the R7 BIAS pot. So I  did it that way. (the above may work faster and better) The lamp is a fuse.
I'm attempting a 2 way protector the lamp and the Silicone fuse, is in series. (one slow other fast acting)

SECRET #1:
Lots of secrets,  here the R6/R7 act as a dummyload (and test bias) in the tester for the 5Y3 and my new diodes, effective kills the tubes on Vf (forward resistance, the 50vdc drop is gone)
My tube mode (solid state =SS) raises the 5y3 from 200 to 250vdc, upsetting the calibration greatly. 5y3 are not easy to find today, common then not now.
They sell or we can make a SS version of 5y3 easy or just buy the SS substitute:

The USA #83 4 pin tube is also rare and dangerous. so do not break it. (toxic mercury inside)

I also discovered a secret, a calibration copper tab on the 100 % end of the POT, CW (clockwise max) on mine top rear pot terminal.

The cure is 2 new parts , a news main English BIOS pot and a new series, (ends) calibration pot, my modification makes it now safe (no  hot shaft) and very easy to calibrate with my BOGEY TUBE>

Experiment 1:
I added a 500 ohm 5W pot  in series with the  pot below. hidden inside. on bottom 100% end, pot wire.  (3watts or more spec, any percent is ok)  Mouser.com has it, in stock $5.
My new SS solid state 5y3 upgrade makes Vf 50 volts higher, now 250vdc and makes calibration wrong,. no big deal here, my old pot is burned up and can not be bought on planet earth. (only sub'd)
Use a new R6a I call it,  500 or even 1000ohms. (by your needs or luck finding parts)
The trick I use is to get my 6L6G tube to read correctly a real BOGEY Tube used here, and turn the dial on the new R6a trim pot to read the stamped bogey tubes standard.
 
Lets call this 2nd new pot R6a,  so R6 fixed and R6a are wired in series on the way to the R7 center tab.
The new R6a is 2 watts and  will burn up before new higher wattage R7.  (or never if the factory #49 fuse lamp modification, is in place) (< this is all for shorted tube protection under test failures)
  • R7 buy a high wattage you can find  (1watt is no good, go 5w)
  • R6b keep it low say 2watts. to protect R7
  • install the #49 lamp bulb (with socket) in this R7 bottom leg. to R6a/b. This is a factory upgrade not any kind of hack.


Here is where I began, with this bad pot.
Here is what my stock BIAS POT Device...looks like,  see strip down below and the secret hidden calibration trim device inside. omg.
My new pot is a  linear taper 3000 ohm pot.     3k ohm wire wound  pots made today are super like (chicken lips) Think a deity, for NOS parts. 3k ohm get them while you can.
Man KILLER #2, If you touch that naked 1/4"  shaft you get electrocuted  !   250 volts is not safe for humans.
With a new R7 pot we avoid this horror from 1945 ! no death. Just pulling the knob off invites a huge lethal shock.
See the washer next to the nut  below , that is RUBBER, and keeps the top metal panel from going to 250vdc., and you now dead. (or kids playing) see killer fix #1 here.


Above see that copper strip secret there is a jam nut on that strip that is a POT calibrator,  English R7 POT. (grid BIAS)
This table below shows the differences from the 2 POTS R7, old and new.  This can help you get the dial reading correctly.
Dial is % mark on English dial

steps:?
  1. I insert my 6L6 Bogey tube in the 8 pin octal socket.  (glass tube or metal no mind)  6000 is par. Seen on ebay cheap.
  2. Set the switches per the chart, 6L6GT
  3. I set the English R7 Bias pot to the chart for 6L6. seen as dial above %
  4. I turn on the tube tester now.
  5. I just tune the R6a trimmer pot I just added (mod) so that GM METER DIAL reads the same as my BOGEY is stamped,



More inspections , cures, modifications, and refurbishments:

The wiring if bad, is an easy fix.  I'd replace mine with Mil grade stranded silver tinned, Teflon wire, as needed.
MOD's:
Upgrade 1  is , new 3 wire line cord with safety ground.  (I standard instrument cable and connector will be used on mine, just like I do on my Heathkits.)
 You won't like  225vdc on the case top, would you.? (yes, a shocking , era then... and very LETHAL)  The rule on this  (mine) enough voltage to shock you and enough current to kill you. (easy no?)
If working live circuits,  set up power unplugged, then connect meters and jumpers to nodes, then with one hand in pocket, plug in the line cord, to power, then keep both hands in pockets and read the meters or scopes.
AND LIVE. (have rubber sole shoes, avoid leather soles, that conduct )
Next up?:
The worn old  tube sockets are easy to buy new, the big pushbutton switches are life time serviceable, just clean them. (I burnish the contacts using strips of cut printer paper, never sandpaper of any grade )
I modified the 2 internal rectifier tubes for solid state plug-ins. (#83 and 5Y3, both sold on ebay, cheap)  (83 is a toxic mercury rectum frier)  A $20 cost or less.

The next mod. would be the classic 2 diodes back to back on the meter, limiting the input to the meter to 0.7vdc protecting it, from worst case shorts to power. (BTW: this meter is 100mV meter, so Schottky diodes be best here)
Best diode is...1N5817
This MOD can  in fact ,save the meter from blowing up. (the meter that can not be bought, BTW) If you linger on fleabay for 1year, you might find one, yes, RARE.


My Restore will be to just get it working.  (no beauty fixes, but will be cleaned OCD)
I have  schematic, a roll chart data ,  and the books on it. Best roll chart is 1961 issue.

Wafer madness, look , ponder, and be happy this era ended:
Learn first that the wafter contacts are silver plated and all silver turns black (silver oxide from our AIR's oxygen caused) but is not really a problem, and is seen in all gear with silver switches.
Leave them alone, is best, the books say clearly ,cycle the switches end to end to self clean the contracts,  do it now.
I cleaned mine in pure (near) Alcohol  (true name is Ethanol) or IPA (ask any nurse what that  means)
If you prove it is a problem and need the sliver cleaned. This is the only way to do that. (Used by Mom, or Wife that cleans silverware or as Silver Trumpet.
This substance even slows further tarnishing.  I just dob it on with a tiny brush, let it sit a spell, then clean with IPA (hospital grade, Ethanol/Alcohol)

Last resort, for proven switch failures that Alcohol scrubs do not cure!:
If the contact silver is real bad I use, Tarn-x to clean the  contacts, but only for seconds and then a fast flush with Alcohol. 
Here is  Tarn-X , MSDS sheet, data.  (I  avoid any product that have secrets ingredients in them. I do know that most cleaners sold in USA all have a MSDS sheet and the word secret is missing .
Excerpt: MSDS 2017:
note how the word SECRET is not here.! 
The never do lists, are endless, in today complex world: but...
NEVER DO:
Never use Tarn-x and just walk away, or risk loss of all silver plating, this product is a chem dip for silver, and works with no  scrubbing.  Tarn-x is for last last resort.
The #1 goal is to not wreck the silver plate on the brass switch tabs. (inboard) and not allow the wafers to suck up ,oil or other crap.
Never soak parts overnight in Tarn-x . (seconds only if at all) (dob on with Q-tip only) if at all. (this is only done in desperation )
Never use abrasive cleaners of any kind here. (no Brasso ever)
Never use paint thinners of any kind, use only IPA to clean. switches, (iso isopropyl acolhol, or Ethanol) never use acetone, MED or lacquer thinners ever.
Never use water to clean gear.  (it's very hard to bake out and can cause damage if it gets deep enough, like inside the transformers , wafers or other places...)
Do not put oil or WD40 (it's oil) on the these wafers, ever.  NO GREASE or OILS of any kind,  or you will be very sorry.
Do not buy and use super expensive SNAKE oil stuff , here. (junk science crap) NO-OX-ID  ( see the word OX , AVOID like the Plague)  you will be sorry2. NO-OX has a purpose but NOT HERE.
The switch  contacts and wafers came new oil free. (factiod #1)
Only the rollers on the bottom are greased. ,  I used automotive BRAKE grease there. (will never melt ) 


The bottom line is do only what is needed to get the switches working and stop. (do not OCD it , as we say today)  The black seen above 100x more scary than truth. (it's mostly ok)
Mine now looks like this: (close up view)
I did not need to use Tarn-x (after a huge alcohol flush and wet brushing)  I do bake it dry, 120F oven or attic dried. (same temp btw)


How those wires can look and be good after 70 years, is  magic to my eyes.

Day1 Tests ?,
Inspect inside switch (rotary) and wire (hacks) for damage and get  new power cord 3 wire.
Turn it on, if it will not glow the power lamp (if lamp not burned out) then the fuse lamp is burned out. (replace, them as needed)
Make sure all transformer outputs are good.
The tests here work good , for 6v6,  then  check the bottom of case tube voltages and there DC (pulsating) outputs.


I test all resistors and switches, and clean all switches. (all my fixed resistors in mine , test good)
Keep in mind they are all +-10 or 20 % spec. parts accuracy back then , for sure on all wire wound resistors and I'd hope the silver 10% band (CC-carbon Comp)or missing tolerance band is (20% they are) is clear to you... 
Repair all bad wiring, (Teflon wire is best )
Repair all bad sockets, (buy new ones with gold pins and ceramic are like $2 now, bingo)
Replace all bad fixed resistors, seen at mouser.com . (look under all wafers, see hidden  47 ohm carbon comp's there, sure. test them , in circuit.
Pray the English DIAL POT , never fails. (ganged pots are super super rare now)

Reading a cool web site called the Tone-lizard, I passed all his tests but  failed hard the bias pot test.
My pot worked for like 1 day and failed, and the tester passed my 6V6 tests.
My rig turns on and my line set test works.
My meter works.
The bias pot is dead.  Replaced it with a generic pot and then used resistors to trim it for same readings at 50 on the dial.
I tested all 6V6 and 6L6  bogey tubes , all pass my tests, and all tubes in my old Heathkits read correctly (spare tubes I stock)
My cure:
Got a new generic BIAS 3k ohm pot with 4 times the watts rating.
I added  BIAS  adjuster resistor so my 3k-4watt, linear pot, (see classic tapers a here, the USA tapers are C1 C2, etc, and is a Hickok SECRET what they used)'

I added the Hickok factory mod (1951) that puts a  GE#49 bulb/lamp on the center BIAS lug to prevent Pot burn out with shorted out tubes.
This tester transformer adds 5vac RMS signal to the DC bias (7volts peak that is and is a sign wave on top of pulsating DC,  there is no name for that mess,,,, but will be in SYNC as will be the plate voltage, pulsing)
I added a CAL POT (500ohms)  ,to mimic the factory copper trim tab seen above. (it is near useless)

More secrets:
The main Gm meter is full scale at  0.114vdc(my test data) (100mV that is) (I installed 2 back to back 1N5817 diodes across that meter for protection. as seen from 1970s to now , on meters like this)
This mod at least assures 250vdc never ever lands across those 2 meter pins.  (2500 times too much is BOOM let smoke out , failure mode)
I tested my meter  un plugged.  so FS is 100mV. (so the magnet is 70 years old and still like day 1)
The BIAS  Pot wires are .002 inch diameter, or 44 AWG. (hair sizes.)
My new  linear pot works great, as does the calibration secret  (my new pot  is 4 watts, 400% stronger)
I have lots of secrets on the transformer, seen below.  (turns ratio, amps, and volts) Amps is not actual, it's max allowed, by by any output , no others used. Its a max per winding, exclusive of others.
My wall power is 123vac, not 115vac like it was back in 1945. But the line level trim on mine works like day 1.
 


That Transformer: All I know on this part is below:

. CLICK PHOTO TO ZOOM IT !  I solved the volts and ohms here, using AWG rules and turns ratio rules.

Below is my ultra High Resolution 6k pixels,  click the image below to see that full size drawing. Note how Hickok forgot to show wire colors.
Icon #1 for full HR schematic:  532.  I have  5Y3 , that is SILICON DIODE upgrade .  83 is toxic mercury tube. Do not break it !
No wire colors and no pin numbers of tube shown but those numbers are standard, 5pin socket pin 3 is top.  the others are all CCW pin 1 max. and CW Max is max pin # (like the OCTAL is)
The socket wiring below is REAR viewed only as wired, we call this.


See my meter protector (diodes back to back)  The BIAS pot must be upgraded with a FUSE or  #49 series wired lamp to R7
Back in the day everyone knew this (not now) how tubes are wired an pin counts. ( USA rules never European or Mullard Valves)
This is the standard then, and note always a rear view due to that is the only way to wire solder the pins, from the rear.
Note the 2 skinny pins, 2/3 on 4pin tube.  The fat pins are always FILAMENT for the huge current those need are large. (see fat pins 1 and 4 below?)
Note the OCTAL key is show down, showing pin 1 end, pin one is always CCW max. per below drawing.  5 pins is the most weird of all,. but is seen below, right.  (the below is for just some sockets)



I will not do all sockets here, just find what tube fits your  socket, and get the data sheet for it,  easy ,just Google it, like I did above.  Most gear running today use only 7/9 pin miniature and OCTAL.
4 pin are WWII or older. Old Radios from the 30s were full  of  4 and 5 pin tubes, we never see those now, but sure collectors do.

Here is my new slide show of 532 inside and others. (and 9 pin upgrade)
CLICK here for SLIDE SHOW:



Very old advertisements (ADS) as old as 1945.
Adjusted for inflation 1955, is  $1,624 (ouch)  The 600A is far better.  (as is 6000a)
Find one of these and avoid 1945;  below is seen used for $300 to $400 . 6000A    Find one and buy it you will not be unhappy if the tester is not a wreck inside. (ask for photos first , real)
This was THE DREAM machine,  . $450 then. (and now) wow.


B&K :  My  dream come true, what a rig this is. Mine is mint condition.
I also own a B&K 747B tube tester, too from 1975.  (despite rumors on meter not in Gm values) (the dial is in % of spec'd exact tube Gm !)



Best links: some fail now for non SSL support sadly....

https://www.jacmusic.com/Tube-testers/Hickock/750/index2.html

Mr.  Robert Tomer 1960, "Getting the most out of vacuum tubes" (page 59 to page 79  ) He has NO SSL certs., so I use this search to find this free page.
   165 pages total, short and one of the best books in print on this topic and is free to read, on the internet.
I have great  DVD with 250 TUBE books 100 years long, (pdf) , on tubes, but the above is my favorite. 

I get my calibration (refr) tubes from this Guy. "These tubes tested good on my Hickok 6000a tube tester. The tester was just calibrated by Paul Hart."
This tube "bogey" PDF (old name) no SSL here. (only searching finds his pages old)

What is the distribution bell curve like on new tubes. (old ssl page dated, but zero risk click ok)

A great page with correlation  data is here.( I was shocked at the good consistency )
(old ssl page dated, but zero risk click ok) The TONE lizard is a cool site.

Best tube data sheet archive? Franks (and mirrors) SUPER GOOD SITE !!! (SSL is good linked site)

If you dig deep you can see what B&K uses for Gm model 500.  (so when you see 100%  on there newer tester for 6L6 , they mean 6000 Gm) 100% means BOGEY tube.

Unified B&K Tube chart.

BOGEY: (simply a calibrated or known GM tube) NO NOT HUMPERY BOGART. (no not General Motors) GM is transconductance
The best way today to get such a tube is ease on EBAY.com sellers sell them and are labeled as to its GM reading just this tube, on specific tube tester.(stated)
What is a BOGEY tube?,  it's a tube that matches the Datasheet, which is an average of all tubes made by the maker,  (a center point of all tubes sold)
A box of new tubes say 6L6 can vary greatly 20% ,but the GM of this BOGEY tube solves that reality.  (and is stamped for GM by ebay crafters many)

These OEM (RCA) Real Bogey tubes are not sold now,  the makers of tubes are not in business now to make tubes.
The new tubes(or NOS) are aged for 100 hours, for stablity, then GM tested.
Today a  BOGEY seller works  from NOS tubes boxes of  new old stock tubes and tests them. (ebay)
The tester will never match GM perfectly due to all non abolutes listed below and more.
Calibration:

The best document I've seen as  guidelines is this, by Mr. Shoo.(539c) use it as a baseline guide to doing yours.

I use a calibrated BOGEY TUBE from a seller using my tester and sends a tube with Gm readings (sticker) he measured,  and then I adjust my new Secret pot to match my BOGEY.



Gas: Tubes can gain GAS over time, (not always) but mostly with plate over heated, glowing red plate? ouch.  (too hot plates boil out deep gas in the metal (nickel?)
If the glass is not cracked or pin seals bad,  the way to get rid  of minor gas is run just the filiments. (for 1hour?)
The hot filiments heat up the magic GETTER device inside and this device vacuums up(a pun) the GAS. (barium = getter) and eats up that gas.
Some tubes even have Plate (anode) coatings that eat gas for the life of the tube.
If you see the blue or purple glow , the tube is gassy.  (USA tube) some cheap knock off tubes (vacuum tubes) made outside USA, have gas just on the inside of glass and is not bad.
No gas is allowed at Cathode,grids or plate area's deep inside that zone of thermionic emissions.
I tell all this here, because the tube tester can run the filiments powred on only , all day long, a useful feature. (for gas reduction).
Even to the point of starting the filaments at lower voltages for hard nut gas cases(real bad). like 1/2 of 6.3v  or 1/2 of 12vac.  (any tube tester just turn the knob)
If super  curious read how GETTERS work, to eat gas.(1950 work and  republished 2000)
I have a cache of tubes here 60 years old still 100% good and no gas. (proving time is not the top reason for gas,  for sure testing NOS tubes never used for 60 years)
Abuse is #1 reason. (dropped tubes or running crazy wrong, plate currents grid currents to name just 3)  ( a rig with a dead fan, the tubes run hot and fail fast, pg25 Tomer)
Most tube arcing is gas. ( do not allow arc's ) shut it down and test the tubes first.

Not all gassy tubes are bad,  as TOMER TOLD You, 1960.  Some even made with no Getters at all, some with 2 getters. some the getter is only a PLATE coating, no human can see.(Tomer Pg. 23)
Some tubes having gas will wreck the cathode fast. (the maker knows that and has getter for sure here)
Barium The active ingredient of most flash getters is. barium, which is used in combination with aluminum,magnesium, tantalum, thorium, strontium or calcium.(citation)

Absolutes: ( dreamers "?) no this a BLUNT INSTRUMENT. A hard cold fact but useful as no human can see feel  or hear GM transconductance..
  • There is no such thing here, for Vacuum tubes (a.k.a Fleming Valves)  the tubes vary by maker to maker or 1 maker by  (+/-)40%  that was the spec.  citation: (per page  64  by R.Tomer)
  • The resistors inside are off by 20% (Rload)? 
  • The AC line voltage is now wrong, yah 10% higher. (110vac is gone now)
  • The tester has no DC voltage regulators. making above fail. (bias is now too high and dial reads wrong %)
  • The tester tests the tube with the wrong BIAS , and therefor GM reads wrong, or simply a tad  low, but is in spec. none the less.
  • Or far far worse the near useless grid emission tester.
  • Keep in mind most gear made from 1930s to mid 1970s tube based are not run at extremes at all by DESIGN and for longer life spans. So in most cases weak tubes work great. (so  unlike computers)
Tomer (1960) told this (page 55)
Natural variance Gm on new tubes is huge.  (and maker to maker oh my golly  more)
70% sample size is 33 % variance and 95% sample was 66% variance from center average readings, (Gm)
We like to say I can drive truck through that hole.?

Tubes are not ACCURATE, at all. (all designers know this fact and make RADIOS that work perfectly in the low end of Gm RANGE )
The tester  is also poor in  accuracy with BIAS, but 1970 is good year to own one and not have 10 times more errors. (see on WW2 testers)  20% error?
The only way to get more tester accuracy is to employ super accurate BIOS supplies "regulated too", (stable and long lasting and dead accurate , as seen TODAY)


My early history related to Electronic thermionic vacuum tubes:
Most tube radios ended ( like clock radios) in 1970,, I was in USN then fixing you guessed it a ship 99% full of vacuum tubes, I worked on all the gear on that ship, even the HF transmitters and Radar/ECM. (ET2 rank)
The TVs are very hard to track due to it having a CRT and many TVs are 99% solid state, but that one huge tube is CRT.  (the 1967 Motorola Quasar TV "works in the drawer"? solid state, with CRT)
The First SS radio's home or  car were hybid, all tubes but the final speaker amp, On TVs they could not do HV SS diodes at all or were "love to blow up" kinds. so Tubes in the DOG HOUSE were tubes not transistors.
Imagine the poor engineer trying to find  transitor for  6BK4 tube, ouch, not possible in 1966 or so...not until  later. and its nasty Xray tendencies with 2 failures..  or the huge sweeper tube, Horizontal output...
There are many folks that  still love old tube radios, so they live on.  Hams do too, some have super good and very sensitive receivers,.unlike many SS gear. (high gain RF front end amp and adjustable, is king in my book)
Personally I like it all.   (SS = Solid state or as they said then All_transistors)  "Lets go the beach Joy said and Jane said the hey, Joy lets take the Transistor."

version 7 .  1-01-2017  (added, bias pot cure, and Gm  facts)  , minor edits Aug 2020. (https (SSL) updates