alignment generators ?

[jshorva65]

Originally Posted by Tube TV

Thanks for the tip on using a dry erase pen on the oscilloscope .
I'll have to remember that one.
I was talking to the guy that is selling the unit to me and it does use a crystal , and he has it and has sent it with the unit .
It should be here in a few days .
I would amagine I should do a recap on it . and will have to clean the controls .
I think it was made in 1958 .
Would the crystal be for creating a marker frequency ?

A recap is definitely indicated here, as is a calibration check-up and recalibration if needed. The manual will generally specify a calibration tolerance. All of my test instruments get an annual check-up and recalibration if factory-specified tolerances aren't met. If it's an external crystal, then it's probably for a marker frequency. Most generators were shipped with a 4.5 or 10.7 MHz crystal and other frequencies were available from their Parts departments as accessories. Some use an internal crystal reference oscillator for checking calibration "on the fly" in between annual check-ups. When verifying or recalibrating, I use a modern solid-state (Elenco 9500) generator with built-in frequency counter as a reference.

Also, I highly recommend obtaining the manuals for ALL your test gear to perform check-ups and calibrations regularly. My B&K 707 tube tester had drifted somewhat and was showing Good tubes as marginal and marginal tubes were testing Bad. After obtaining the manual and following the procedures for setting the Balance, DC Bias and Signal Amplitude back to factory specs, I'm getting the accurate tube test results that were the reason for my buying a Dynamic Mutual Conductance tester in the first place. Also, beware of poor solder connections in 60's vintage gear using early PC board technology. My RCA WV-77E had issues with pin 7 of the 12AU7 and would intermittently "peg" the meter spontaneously. The fix was to unsolder and remove both tube sockets, clean each contact and PC trace, then reinsert and resolder the socket connections. The sockets were sitting up too high so the pins weren't protruding far enough through the board to make a secure joint. Thermal effects on the pins cause a hairline fracture at the joint and some pins had "pocket" joints. Pin 7 was the worst of them, and the "floating grid" condition it created would throw the circuit wildly off balance. It actually damaged the original 12AU7, which I needed to replace along with the solder joint fix. Basically, the zero-bias operation resulting from the floating grid "stripped" the cathode of the affected triode section and caused one side of the tube to go prematurely weak.