What is the "147C" amplifier used for, what battery does it use? P/O "TST 191set

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MisterBill2

Joined Jan 23, 2018
12,690
Just bought a nice looking test set at an estate sale. It looks to be unused, but the exact application is not clear. Unfortunately there is no clue as to the battery type or voltage, which makes it challenging to play with. The battery would be rectangular with a terminal on each end. But with no clue as to the voltage I am reluctant to start experimenting. The tag on the case dates it as shipping in 1989, so it is not current technology.
The amplifier, from what I can see, has three transistors, black plastic types, but without a lot of disassembly I can't even see much else. Hopefully somebody who has used one can provide me with a bit more information.
Thanks for any help, in advance.
 

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MisterBill2

Joined Jan 23, 2018
12,690
Pictures of it please...
I am hoping to get responses from folks who have used this tool, because certainly it is a test tool. I will see if I can get pictures, no promise at all, though. And a picture will not help with discovering the battery voltage, which is what I am most interested in at this time.
 

Thread Starter

MisterBill2

Joined Jan 23, 2018
12,690
What is a “test set”? That is not a term in common use as far as I know.
A "test Set" is a collection of tools and accessory items needed to do some type of testing task.
The TST 191 is a nice carry case that contains the 147-C amplifier, a set of probes that plug into the amplifier, a shingle headphone that plugs into the amplifier, a leather case for the amplifier, and a shoulder carry strap. But no instruction book, in this instance.
The 147 C is a grey aluminum box about 4 by 4 by 1 1/2 inches, with two knobs and 2 1/4 inch jacks. One knob is a switch with two positions marked "probes" and "coil", the other knob is marked "volume". Inside the 147 C enclosure is a small circuit board and a battery clip as I described initially. The battery would be rectangular with one contact on on each of the two narrow sides. so it is not like any battery that I am familiar with. I hope to discover the voltage so that I can assemble some standard batteries into a battery pack.
Given that this device was shipped in 1983 it was probably not a lithium battery pack.
A small amplifier like this could be useful for a number of things, I hope.
If somebody has actually used one of these i would like to hear about it.
 

Thread Starter

MisterBill2

Joined Jan 23, 2018
12,690
Thanks, Bertus. It appears that I got a much better deal, especially since the unit in the picture is missing a knob. So now folks can see just what I am asking about. Western Electric primarily supplied the Bell system, so it was probably used by phone companies. So somebody should recall what battery it used. I hope that they would share that information.
Mine seems to have not even been used, the plastic bags are not torn open, even . 49 years on a shelf?? Oh Wow!!!
 

Thread Starter

MisterBill2

Joined Jan 23, 2018
12,690
seeing what is on the PCB will be a challenge, this amplifier is built tough enough for tactical infantry use. And that still would not get me the battery voltage.
 

Ya’akov

Joined Jan 27, 2019
6,260
Hello,



Did you see the 3 batteries in post #6 ?

Bertus
I am familiar with the 412 413 having seen it in old instruments. But dimensions are different on the others, I believe, so that should show which is correct.

EDIT: Now that I look at the 412, though, I do recognize it from the same types of devices (VOMs, etc.), mostly I recognize the 22.5V.
 

Thread Starter

MisterBill2

Joined Jan 23, 2018
12,690
I am familiar with the 412 413 having seen it in old instruments. But dimensions are different on the others, I believe, so that should show which is correct.

EDIT: Now that I look at the 412, though, I do recognize it from the same types of devices (VOMs, etc.), mostly I recognize the 22.5V.
OK, now I will need to get out the calipers and measure the battery holder spacing. It seems I did not look closely enough. probably either 22.5 or 30 volts.
THANK YOU!!
 

Thread Starter

MisterBill2

Joined Jan 23, 2018
12,690
I did come across instructions for the newer 191 test set, that includes a 147D amplifier that is a similar size. But that amplifier uses 3 size AA cells for a total voltage of 4.5 volts. I also learned what the set and amp are for, which seems to be checking phone system circuits for shorts and leakage. It uses coils, which are not what i have, and probes, which I do have. But the battery holder in the set must use a cell holder, because what I have will not hold AA cells.
 
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