Unknown Vintage Test Equipment - UK Vintage Radio Repair and Restoration Discussion Forum

backflipper · 20th Nov 2017, 5:21 pm

Hey all
I just picked up some old HP logic state analyzers and there was another piece of equipment that I picked up which I have no idea what it is.

It has:
2 inputs (Record +/- and Audio Osc. +/-)
1 Output (Tube Volt meter)
2 multi turn dials.

It's pretty basic inside and only has 2 variable resistors controlled from the dials. The schematic would look like this:

+Record >---+
/
50 ohm /----> Tube Volt Meter +
/
-Record >----+

+Audio Osc. >---+
/
50Kohm /----> Tube Volt Meter -
/
-Audio Osc. >----+

Can anyone tell me how it may have been used?

[Edit] Added quotes to schematic to keep the formatting correct.
[+Edit] That didn't work!!!

backflipper · 20th Nov 2017, 5:30 pm

Ok I have attached a crude schematic

Station X · 20th Nov 2017, 5:47 pm

Can you post a picture of the actual item?

backflipper · 20th Nov 2017, 6:01 pm

Yes I can.

Attached.

Station X · 20th Nov 2017, 6:08 pm

Looks like some kind of comparator/calibrator.

If the two inputs are equal the meter reads zero depending on the settings of the input devices and the pots?

backflipper · 21st Nov 2017, 12:55 am

Thanks!

20th Nov 2017, 5:21 pm	#1
backflipper Tetrode Join Date: Mar 2010 Location: Haslemere, Surrey, UK Posts: 73	Unknown Vintage Test Equipment Hey all I just picked up some old HP logic state analyzers and there was another piece of equipment that I picked up which I have no idea what it is. It has: 2 inputs (Record +/- and Audio Osc. +/-) 1 Output (Tube Volt meter) 2 multi turn dials. It's pretty basic inside and only has 2 variable resistors controlled from the dials. The schematic would look like this: +Record >---+ / 50 ohm /----> Tube Volt Meter + / -Record >----+ +Audio Osc. >---+ / 50Kohm /----> Tube Volt Meter - / -Audio Osc. >----+ Can anyone tell me how it may have been used? [Edit] Added quotes to schematic to keep the formatting correct. [+Edit] That didn't work!!!

20th Nov 2017, 5:30 pm	#2
backflipper Tetrode Join Date: Mar 2010 Location: Haslemere, Surrey, UK Posts: 73	Re: Unknown Vintage Test Equipment Ok I have attached a crude schematic Attached Thumbnails

20th Nov 2017, 5:47 pm	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Unknown Vintage Test Equipment Can you post a picture of the actual item? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

20th Nov 2017, 6:01 pm	#4
backflipper Tetrode Join Date: Mar 2010 Location: Haslemere, Surrey, UK Posts: 73	Re: Unknown Vintage Test Equipment Yes I can. Attached. Attached Thumbnails

20th Nov 2017, 6:08 pm	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Unknown Vintage Test Equipment Looks like some kind of comparator/calibrator. If the two inputs are equal the meter reads zero depending on the settings of the input devices and the pots? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

21st Nov 2017, 12:55 am	#6
backflipper Tetrode Join Date: Mar 2010 Location: Haslemere, Surrey, UK Posts: 73	Re: Unknown Vintage Test Equipment Thanks!