Hansen 'ZQM-2' Transistor Checker
 

Bought this for a fiver - an impulse buy. Yet again, nostalgia has triumphed over common sense! :-)

I believe they date from 1963. It's nicely built and seemingly unmolested - as good as the day it left the factory. There are no active devices in it - just 'switchery' a pot, and ten resistors, (plus the meter shunt and rectifier). Ordinarily, I'd expect that some, if not all, of the resistors to have drifted high after more than five decades. However, they appear to be wirewound, so may have retained their original value. The markings on them are unconventional so I can't check them for accuracy. EG: '2Z0, 0Z5, 0Z1', 0Z2, 0Z7.

I've search online for a manual, but nothing has turned up. Plenty of images, several for sale, but no information. EG:

https://picclick.fr/Hansen-Transisto...785855632.html

I've seen this style of transistor checker many times at rallies, possibly under different brand names, but basically the same thing. I've got several modern digital transistor tester which test both silicon and germanium transistors, so don't really need to use this, but on the other hand, it's an appealing thought to be able to check transistors of a similar vintage on this tester.

I'd appreciate any information anyone might have - a source of the instructions/manual would be even better, but I say that more in hope than expectation.

Re: Hansen 'ZQM-2' Transistor Checker
 

I used to have an Eagle:

http://htspark.blogspot.com/2013/05/...del-tt145.html

Captured "Manual" image here:

https://www.vintage-radio.net/forum/...5&d=1271785720

?

Lawrence.

Re: Hansen 'ZQM-2' Transistor Checker
 

Alpha and Beta are rather vintage terms themselves, now.

I think those resistors are carbon comps so are well worth checking and swapping as needed.

It's not a badly made thing at all and looks quite useable.

David

Re: Hansen 'ZQM-2' Transistor Checker
 

Thanks for that Lawrence - really helpful.

As well as being called the Eagle 'TT145', it seems to have been marketed as the 'TTC C3022' and 'Alcron 22' - all seemingly identical apart from the branding.

Re: Hansen 'ZQM-2' Transistor Checker
 

I have two of the same:

Reace (no model number) and TTC C3022.

Solidly built and useful for go/no-go tests on Si/Ge bipolar transistors and diodes.

Re: Hansen 'ZQM-2' Transistor Checker
 

Yes, what was Beta has for some time been hfe.

I'm pretty certain they are wirewound David, because one appears to have been overheated and the paint burnt off, though it's still intact and appears to be R10 - 10 Ohms. I can see the turns of wire through the paint on the others. When I've sussed out which is which resistor, I'll compare them with the stated value. One is marked 0Z9, but the only resistor in the list which has a '9' in its value is 190 Ohms. There is a 0Z7, and the parts list shows a 7K Ohm resistor.

When I get a bit of time, I'll measure the resistors, make a list and see if the values can be matched with the parts list.

Now that I have the user instructions, I may find that it works as it should do.

Re: Hansen 'ZQM-2' Transistor Checker
 

RM has a slightly less fuzzy TT145 image here:-
https://www.radiomuseum.org/r/ttc_tr...?language_id=2

Re: Hansen 'ZQM-2' Transistor Checker
 

Thanks for that link George - much better.

I’ve been out of favour for some time with RMORG as I have nothing worthwhile to upload.

Everything I have has been uploaded to RMORG many times over by others, so am seen as a ‘taker’, not a ‘giver’, albeit when I joined many years ago I made a financial contribution. As I’ve not logged in for some time, I had to re-set my password, then got the usual red letter warning that I’ve all but used up my allocation of points.

Nevertheless, I’ve managed to download and print the info and it is indeed, much clearer.

At first sight, the circuit looks deceptively simple, but there is a total of 40 switch contacts and the ‘rats nest’ of wiring makes it a challenge to identify which resistor is which. The marking on them appear to relate not to their Ohmic values, but to their designation on the parts list. I’ve identified a few and confirmed their position in the circuit by comparing their actual value with the parts list.

As it’s not been messed with, it may work fine, so I’ll try a few transistors on it and compare the results on my digital testers.

Re: Hansen 'ZQM-2' Transistor Checker
 

Yes, it seems to work well.

I've tested a germanium PNP transistor on it and also on a couple of digital meters, and a Peak Atlas meter for comparison.

They all show the same 'beta' (hfe): 30.

Hardly an exhaustive test, but a test, nevertheless.

The peculiar markings on the resistors seem to relate not to their Ohmic value, but to their circuit designation, though oddly, out of step by one. For example, comparing the resistance values with the numbering printed on the bodies of the resistors that I've been able to identify so far, (all within 50% of their stated values), they are:

R4 '0Z3'
R5 '0Z4'
R6 '0Z5'
R7 '0Z6'
R9 '0Z8'
R11 '0Z9'

The paint has burnt off R10, but it measures 10 Ohms as it should do.

I've redrawn the circuit to make it clearer and have added the component values next to their numbers to make the circuit a bit more convenient to read. It's attached in case anyone finds it useful. It's kept me occupied on a very wet Sunday.

Thanks for the help and interest.

Re: Hansen 'ZQM-2' Transistor Checker
 

Thread moved for posterity

Re: Hansen 'ZQM-2' Transistor Checker
 

It was also branded "TTC model 3022"
I used mine yesterday.

Peter

Re: Hansen 'ZQM-2' Transistor Checker
 

The transistor socket is optimized for AF11x transistors. Perhaps you could modify the unit with a tin whisker evaporation function?