Forums

Anybody familiar with this 'scope?

Started by Unknown July 18, 2014
Greetings Everybody,
My son brought by today an old oscilloscope. The Brand is Lambda and
the model is MM-2. On the back are three pairs of terminals. One is
marked with G & V, one G & H, and the last pair R & S. So the first
two pairs are pretty obvious, horizontal and vertical, but I don't
have any idea what the last pair is for. The screen is about 2 inches
in diameter, and is marked with painted on lines. Two lines, one above
the screen center and the other below are marked carrier frequency.
Removing the cover shows "NAVY" printed on the side of the CRT. This
link: http://www.electronixandmore.com/misc/index.php?item=13 shows
the device. From the web I gather this is a modulation monitor. I
think it was rack mounted. Anyway, it would be neat if he could
connect the thing to some sort of signal so that it would show more
than a stationary dot on the screen. I can buy a manual for 25 bucks
but I'm not that curious about this primitive 'scope. So, any
suggestions? Anybody got one of these? Or a manual that you would be
willing to scan and email?
Thanks,
Eric
In article <m86js9tsn7cplqsdkilqm2br952ub800fh@4ax.com>, 
etpm@whidbey.com says...
> > Greetings Everybody, > My son brought by today an old oscilloscope. The Brand is Lambda and > the model is MM-2. On the back are three pairs of terminals. One is > marked with G & V, one G & H, and the last pair R & S. So the first > two pairs are pretty obvious, horizontal and vertical, but I don't > have any idea what the last pair is for. The screen is about 2 inches > in diameter, and is marked with painted on lines. Two lines, one above > the screen center and the other below are marked carrier frequency. > Removing the cover shows "NAVY" printed on the side of the CRT. This > link: http://www.electronixandmore.com/misc/index.php?item=13 shows > the device. From the web I gather this is a modulation monitor. I > think it was rack mounted. Anyway, it would be neat if he could > connect the thing to some sort of signal so that it would show more > than a stationary dot on the screen. I can buy a manual for 25 bucks > but I'm not that curious about this primitive 'scope. So, any > suggestions? Anybody got one of these? Or a manual that you would be > willing to scan and email? > Thanks, > Eric
Looks like the early days of vector scopes. They used overlays to represent data. Jamie
etpm@whidbey.com wrote:
> On the back are three pairs of terminals. One is marked with G & V, > one G & H, and the last pair R & S. So the first two pairs are pretty > obvious, horizontal and vertical, but I don't have any idea what the > last pair is for.
Some "real" oscilloscopes have a Z-axis input that lets you modulate the brightness of the spot. I don't know if that's what you have, though.
> Anyway, it would be neat if he could connect the thing to some sort of > signal so that it would show more than a stationary dot on the screen.
How about this: come up with a 1.5 V battery (AA, C, D, whatever) and about a 1k or 5k ohm pot. Connect the battery across the ends of the pot and take your output across battery - and the wiper of the pot. In other words: +----------------+ | | | | | \ A - + /<-------o to H or V on scope --- 1.5 V \ | / | | | | B +----------------+--------o to G on scope Hook a voltmeter across A and B and adjust the pot for a small voltage, like 0.1 V or less. Then connect A and B to the scope. The dot should jump a small distance away from the center. It may stay there, or it may go back to the center. If the dot flies off the screen, you need less voltage, and if it barely moves at all, you need more. Adjust the pot and try again. If you can't get enough voltage with a 1.5 V battery, try a 9 V. If a 9 V isn't enough, it might be time to research some more before trying a higher voltage. It is important not to do this with an adjustable power supply, because you don't know how well the inputs on this scope are isolated from the rest of the world. The inputs might have capacitors in series but those capacitors might not be worth much after 60 years. If you hook up a line-connected adjustable power supply, you might get currents you don't want, especially on the "ground" connection. Once you know about how much voltage you need to get good deflection, you can then figure out what to drive it with. It might be interesting to use the left and right outputs of a stereo, to get a pattern that changes with the music. I would use a couple of small audio transformers, with one winding in parallel with the existing speakers and the other one connected to the H or V inputs of this scope. You can measure the voltage on the stereo outputs at reasonable listening levels to figure out what kind of ratio you need on the transformer to drive the scope inputs. Matt Roberds
<etpm@whidbey.com>
> My son brought by today an old oscilloscope. The Brand is Lambda and > the model is MM-2. On the back are three pairs of terminals. One is > marked with G & V, one G & H, and the last pair R & S. So the first > two pairs are pretty obvious, horizontal and vertical, but I don't > have any idea what the last pair is for. The screen is about 2 inches > in diameter, and is marked with painted on lines. Two lines, one above > the screen center and the other below are marked carrier frequency. > Removing the cover shows "NAVY" printed on the side of the CRT. This > link: http://www.electronixandmore.com/misc/index.php?item=13 shows > the device. From the web I gather this is a modulation monitor. I > think it was rack mounted. Anyway, it would be neat if he could > connect the thing to some sort of signal so that it would show more > than a stationary dot on the screen. I can buy a manual for 25 bucks > but I'm not that curious about this primitive 'scope. So, any > suggestions? Anybody got one of these? Or a manual that you would be > willing to scan and email?
** See: http://forums.qrz.com/showthread.php?297229-LAMBDA-MM-2-Modulation-monitor-scope Seems to have couple of tubes inside for DC supply and sweep. H and V may be direct connections to the CRT's deflection plates. Maybe try linking S and R. .... Phil