Hickok 752A Mutual Conductance Tube Tester - *Calibrated* - Near Perfect Specs

Description

Calibrated, Clean, has the same tube sockets as the 539C so you do not need a CA-5 adapter to test compactrons. Exceptional Condition, Specs Near Perfect with PICs of voltage Specs and Calibration tubes being tested.
Hickok 752A Mutual Conductance Tube Tester - *Calibrated* - Near Perfect Specs
Hickok 752A Mutual Conductance Tube Tester - *Calibrated* - Near Perfect Specs
Click images to enlarge
Description
Hickok 752A Mutual Conductance Tube Tester
Has the same tube sockets as the 539C - you do not need a CA-5 adapter to test compactrons.
Calibrated & Clean
Exceptional Condition Inside & Out
Replaced the line-adjustment rheostat with a
NEW AND IMPROVED
version that is more stable and adjusts to the line more accurately. The new rheostat also allows the use of a SS 83 in place of the expensive 83 mercury rectifier.
The 5Y3GT is labeled Hickok and appears to be the original 5Y3GT that came with the tester and it tested as good as NOS.
The
NEW SS 83
is constructed with precision wire-wound Clarostat military spec resistors, Fairchild rectifier diodes, and ON Semiconductor Zener diodes.
Replaced the light that illuminates the tube chart with a LED bulb.
Replaced the AC power cord.
There are POTs to aid with calibration, r5, to adjust meter for plate voltage and 2 additional pots. one for each rectifier tube, to adjust the balance of the 83 and 5Y3Gt which should not be adjusted unless a qualified technician with the proper equipment.
24 PICS THAT ENLARGE ABOVE
Voltage SPECs can be seen in the pictures below. All tests were done with the correct shunt resistor to duplicate 1,000 Ohms/Volt Meter per the 752 calibration instructions included.
Picture 3
shows the plate voltage at 150.2 SPEC is 150 +- 5 volts.
Picture 4
shows the low plate voltage is 69.4 SPEC is 68 +- 3 volts.
Picture 5
is Screen voltage at 130.9 SPEC is 130 +- 5 volts.
Picture 6
is the Low Screen voltage at 58.3 SPEC is 56 +- 3 volts.
Picture 7
is bias voltage at 100 on the dial at 39.3 SPEC is 39 +- 1
Picture 8
is bias voltage at 22 on the dial at 3.0 SPEC is 3.0 +- .2
The AC signal voltages for each of the seven settings tested on
SH at 2.55 SPEC is 2.40 to 2.55
(PIC 9)
x1 at 1.28 SPEC is 1.23 to 1.30
(PIC 10)
x2 at 2.55 SPEC is 2.40 to 2.55 ( not shown)
x4 at 1.27 SPEC is 1.23 to 1.30
(PIC 11)
x10 at .51 SPEC is .48 to .52
(PIC 12)
x20 at .256 SPEC is .240 to .255
(PIC 13)
Bias cut-off voltage tested at 36.3 and SPEC calls for over 30. The bias cut-off is used for the dual tests.
AC Plate voltages tested:
S1 at 19.5 SPEC is 18 to 20 volts.
S3 tested at 35.6 and SPEC is 35 to 38 volts.
S6/Gas tested at 173.2 SPEC is 165 to 175 volts.
S2 tested at 292.2 SPEC is 285 to 300 volts.
Checked the leakage circuit (shorts) with 500,000 ohm resistor and read at 475 on the meter. Specs call for the meter to be between 375 to 475.
Checked the voltage regulator circuit, VR on the multiplier, with 150 volts on the volt meter and read the same on the 752 meter.
Checked the S9/ VR MILLS with results of 50 MA on the 752A meter and external meter
(PIC 14).
All the filament voltages were checked and within SPEC per the min/max filament chart included in the calibration instructions.
Picture 15
shows the filament voltage with the tube in the socket at 6.35 which there is no SPEC for in any Hickok manuals, but critical to get accurate test results. Many Hickok testers can be calibrated, but the heater voltage drops below 6 volts when a tube is in the socket causing inaccurate results and may be signs of a weak transformer.
Picture 16
shows a 6L6 with mutual conductance (Gm) results of 5750. This 6L6 on average tests for Gm at 5750/5800 and has tested as high as 6500, and as low as 5200 on several other calibrated Hickok Tube testers. The 752 uses X10 on the multiplier to test a 6L6 so 575 x 10 = 5750. The needle on the meter is right on 575.
Tested the same 6L6 on the X20 scale and tested a little under 300. The needle is between 275 and 300 so 287.50. 287.50 X 20 = 5750
(PIC 17).
Picture 18
shows a 12AX7 being tested with an average Gm test results from several Hickok testers of 1400 to 1800 on both triodes. Test results on triode 2 = 375.
375 X 4 = 1500
Triode 2
was tested without having to reset any of the selector switches which makes testing dual triodes a lot easier than other Hickok testers. The 752A can test dual triodes such as the 12AX7 without having to reset the selector switches.
The noval 9 pin socket is tight and tested the tube with no issues.
Picture 19
shows a 6AQ5 with Gm of 4100 to 4900 on several calibrated Hickok testers being tested using the X4 multiplier with results between 1025 and 1050 thus 1037.5. 1037.5 X 4 = 4150. The 7 pin socket is tight and tested the tube with no issues.
Picture 20
shows a 5Y3GT rectifier being tested with expected results and using the shunt rather than the multiplier. The
SHUNT
was
cleaned and calibrated
in order to give it consistency. Most of the shunt potentiometers on any Hickok tester, unless cleaned, have become fouled up with the original thick lubricant that has hardened over the past 50 years making the shunt dial very inconsistent. Very important the shunt be as consistent as possible when testing rectifiers e.g., since a small movement of the shunt dial can make a big difference with the readings.
Picture 21
shows a compactron tube 6LF6 being tested in one of compactron sockets that could not be tested on a 539B, 600A, 533A, 752 (without the A), or other testers without an adapter such as the CA-4 or CA-5.
A new AC power cord replaced the old one.
A plate cap wire is included with this 752A
It comes with a DVD that includes Western Electric tube data, calibration instructions, a manual with a full-size one page schematic and obsolete tube data, general tube data, foreign tube data, obsolete tube data, and instruction manual.
The tube data roll chart rolls nicely from end to end and is dated 1972.
All the sockets are tight and tested the tubes with no problems whatsoever.
The bulb for the roll chart was replaced with an LED bulb.
If you would like to pay
extra for new socket savers
do not pay until it is determined which ones, and the cost.
The cost will be reasonable for the noval (9-pin) , the octal, and the 7-pin min. Compactron socket saver are not available, but if you plan on testing a lot of compactrons I recommend you try to find socket savers for both the compactron sockets. They do come available and they can be costly, but they will save your compactron sockets from having to be replaced.
The original Hickok case is solid and the "leatherette" is in decent shape with a few minor nicks in some spots, but still a solid usable case.
There is some light surface rust on the medal hardware and one rivet on a hinge on the back of the tester was replaced with a screw.
NOTE: If you buy a Hickok tube tester not calibrated and you send it to someone to be calibrated you will pay for shipping to and from, as well as the calibration fee. You also have to hope the tester you buy is working and can be calibrated. I will offer one free calibration as long as you pay for shipping and any parts the tester may need, for example a new 83 or 5y3GT rectifier, or any other part, and the tester has to be still be in working condition.
There are several choices for shipping and none include any additional or hidden charges for handling or materials; only what it costs for the shipping period. This 752 will also be insured for full value at my expense.
Please look at the pictures and ask any questions.
If you have any questions please ask before buying.
The 752 series tester was made for the FAA, and the reason for the lights on the meter and tube chart was that back in the 60s in the aviation towers, the lighting was minimal due to having to see the old CRT and radar screens. Thus having to read the meter and tube chart in dark conditions facilitated the need for lights. No other Hickok tester besides the 580 has a lit meter and the 752 is the only one with a lit tube chart.
Please look at the pictures and ask any questions.
If you have any questions please ask before buying.
I have described what this tester is and provided as many pictures possible and this 752 cannot be returned for any reason. This 752 is sold for Parts or Repair. I will insure the tester in shipping at my expense. Security Measures are in place that will show if this tester was tampered with in any way. If you are uncomfortable with anything stated DO NOT BUY THIS TESTER!
This 752 is sold as is for parts or repair and is listed as is for parts or repair. Why Parts or Repair? Some scammers get away with abusing eBay's buyer protection, the age of this device and the nature of vintage electronics, potential user error, and many other things that are out of my control. So do not send me a message asking why for parts or repair? This only means you did not read this and I will not respond.
I have many years of experience working with Hickok tube testers which include working in a certified Hickok warranty repair shop where I did all the repairs under warranty, and repairing Hickok testers that were no longer under warranty. I was replacing Hickok meters in the 80s and for a small fee as a favor for customers and that time building or repairing meters was much more difficult.
The pictures are part of the description so please enlarge them and take a look for better details.
The 752A tests tubes using the minimum Gm values from the tube data which is similar to the 539C and some others, and simply multiplying by whatever the multiplier is set at, will give you the actual Gm reading of the tube. Remember, if you want to get NOS values for a few tubes, not many, that use a different bias setting on a 752, you will have to compare bias settings to a 6000A e.g. tube chart for some tubes; E.G. 12AX7
I offer
1 free calibration
within 3 years of purchase as long as you pay the shipping and for any parts that may be needed, e.g. a new 83 mercury rectifier. Please keep the calibration sticker on the tube tester, or remove and attach it to a separate piece of paper and keep it so I can refer to it upon calibration request.
The test adapter and calibration tubes are not included.
Please ask any questions and look at the pictures for details.
Packed in a 22x18x12" box weighing 31 pound
s
Payment
If payment is not made in a timely manner the sale may be cancelled. If for any reason the payment is not made within 8 hours, the sale will be canceled unless you contact us in advance of the sale, and an agreement is reached. If you make an offer and it is accepted payment is expected within 4 hours unless a previous arrangement was agreed to.
Shipping
There are no hidden charges for handling or materials. You will pay the actual shipping rate per shipper. All tube testers are insured for full value at my expense and packed extremely well and pictures taken of packing procedures.
Terms of Sale
AGREEMENT
Must read and agree to terms below:
Please note and understand that there are no returns on this tester.
All sales are final and this Hickok 752A tube tester is sold for parts or repair only due the nature of vintage electronics that can easily be damaged by user error, or a part could go bad at any time, and because of scammers and thieves. This 752A is sold for parts or repair with no guarantees or warranty whatsoever. I am creating my own web site to sell tube testers, and tube tester accessories such as new meters, which is cheaper than being scammed. I started the site once and will be doing so again under the name "Hickok Meters" since anyone who owns and uses a Hickok tube tester is eventually going to need a new meter. The delay is having to learn Word Press to complete the site.
If you have a legitimate problem upon receiving this tester such as the 83 rectifier was broke in shipping, which rarely happen, but can in high altitudes shipping internationally due to the vacuum and increased pressure, or something got broke in shipping, please notify me immediately. Immediately means within a few hours of receiving it not 36 hours later or 2 weeks.
This tester is over 50 years old and should last another 50 if used and maintained properly, but if directions are not followed and someone tries to test a shorted tube e.g., any tube tester, or meter, can be destroyed in a second. I cannot be held responsible for someone's error. I do however guarantee you get exactly what is pictured and as described. You are expected to read the manual and understand what you are reading. You need to familiarize yourself with the tester and how it functions. Please take the time to do this since it could save you a lot of grief such as pressing the Gm button when testing a rectifier. It is an easy mistake to make and why you need to be careful when using this type of equipment. If you read the manual and use the manual while using the tester until you become experienced, you should have very few problems if any
.
Also, the same tube tested on different and also calibrated testers will usually give different results on each tester. Please do not expect this tester to have the same exact results of a tube tested on another tester. If you expect that this tester will test the exact same Gm because it is also calibrated and all within specs, then are disappointed and want to return it because it tested a tube higher or lower than you expected, do not buy this tester. You are looking to buy something that does not exist and I do not have the time or money to waste on non-issues and unobtainable perfection.
I am not responsible for teaching you to use this tube tester or paying anything if you take it to someone for anything.
This is a 752 tube tester that uses set switch to determine Gm values such as the 533a, 539, 750, etc., thus should be more consistently accurate as compared to Hickok tube tester that us a moveable shunt dial to determine Gm values.
Regardless; this is not a laboratory tube tester and if you expect laboratory tube tester results from this 752 tube tester; do not buy it. This tube tester, due to its age and the nature of vintage electronics, is sold as is for parts or repair. If the tester is damaged in shipping do not try to use it but rather contact me and a claim will be filed with shipper and being refunded will be contingent upon whether or not the shipper honors the claim. I take pictures of packing the tester and it should not be damaged in shipping and packed extremely well with fragile labels.
About Us
Return Policy
we are not unreasonable and this policy is simply for the few that abuse the system. This policy is not meant to deter you from buying this, but to deter the few that forced us to write it and will be enforced if need be.
Be assured that I am the only one testing, taking pictures of the item, and know where this item came from. I do not rely on anyone else to provide me with any testing, or other information with regards to items we are selling. I test the item and take pictures of relevant information which is included in the description. If for any reason this is returned there will be a 20% reclamation charge and you will be responsible to pay for return shipping with no exceptions. It is up to you to know if this will work for your application and we do not sell items just to be tested out to see if you like them. We cannot afford, or be held responsible, to ship items exactly how described and pictured around the world, then have it returned for no fault of ours, then have to pay for return shipping on top of the cost of handling & materials used in shipping that are supplied at no cost.
If you have a problem with an item and it is legitimate, just contact us for a resolution. We are legitimate and more than happy to work with legitimate buyers when an unforeseen problem arises, but we are against being scammed.
International Return Policy & Shipping
we are not unreasonable and this policy is simply for the few that abuse the system. This policy is not meant to deter you from buying this, but to deter the few that forced us to write it and will be enforced. There is under no circumstance returns for any reason. If you do not like this policy do not buy this item. If an international buyer forces a return, the buyer will be responsible to pay for return shipping and a 25% reclamation fee and return shipping. This policy is not negotiable and if you disagree with such a stern policy do not buy this item. If an international buyer fails to pay duty fees, vat fees, or any other customs fees, and the item is returned there is still NO REFUND. We are not responsible for international buyers? failure to pay fees, then have the item/s taking an unnecessary trip in return shipping when items often get damaged.
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