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Old Panel Readout\Panel Meter Identification TIL306/7

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Infrared_Fred:
Hello!
About a year ago I ordered a large box of vintage LED displays from someone on Ebay and included among assorted displays were two nearly identical circuit assemblies that appear to be some sort of panel meter.  The assortment of displays included a single unused (or else previously socketed) TIL306 LED display, which is a seven segment LED display + IC counter + decoder and two circuit boards that had identical looking displays to the unattached one, other than dirt and gunk on them.  It is also possible that they are a TIL308/309 but....whatever.  The circuit boards have the digits in a +-3.5 digit format with three integrated displays and one passive +-1  overflow display.  ICs visible on the front board are 2x 555 timers and a 7474 D-Flip Flop, which I am pretty sure goes with the overflow display based on TI schematics I have read.  There is a second board with a bunch of ICs, but the only part numbers I can read are a LM308 precison op-amp since they are on the inner side of the circuit board.  There also is a precision 10 or 25 turn potentiometer most likely for calibration.  There does not appear to be any manufacturer's logo or identification, although there is a rather difficult to read 62?44A and Made in USA printed on it.  Googling the 62?44A with various numbers for the unreadable one only gave real estate listings or other useless results.  If they are panel meters I am much interseted in using them as is, but for that I would need a pinout or such information, since none is given.  I could take them apart but I wnated to ask here for identification help before I did that since I am a newbie and I don't want to damage them.  Hopefully the pictures below are helpful--please let me know if they are readbale or if you want any differnet angles or anything like that. Thank you so much for you time and your help!

Infrared_Fred:
I am trying to post more pictures but it isn't working for some reason.  Here is try three.

Infrared_Fred:
More pics...

Infrared_Fred:
The final ones.. I am not rrying to spam but it wont work otherwise.

CaptDon:
Not sure exactly who made those, there are so many to choose from. I serviced a bunch of panel meters from Simpson, Non-Linear Systems and several others that were in our locomotive simulator panels at the GE locomotive factory and the guts were all very similar. They were all built to the same 'DIN Cutout' dimensions. Most were internally 0-200mv D.C. with scaling resistors for voltage or shunts for current. They all used transformers for line input and typically 12vac output for the circuitry and therefore you could safely measure voltages that may or may not be related to earth ground. For instance you could use a 0-200vac meter to measure leg to neutral on a 3-phase 208 source while also powering the panel meter from the source, or either of the other two phases. If you had a higher scale the internal isolation would allow you to measure leg to leg of a 208 circuit while powering the panel meter from leg to neutral (for a 120vac input rated meter and perhaps a 0-400vac scale. They are handy.
I have seen similar meter guts to yours also inside digital panel thermometers.

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