[Test-Equipment] Blank Spots In HP8640B Tuning??

[Steve Harrisonusa]

>You might have the common problem with the 8640b range switch
>contacts - they become loose.

No, thought I made it clear that the problem is when the oscillator is
tuned. All the switches are fine now (I had to repair about 9 years ago,
similar to how Jose did his).

Just downloaded a 400+ page manual from the Premium-RX site, have to go
have a looksee at that.

About the fan...... what I'm worried about is that it appears to have
plastic endcaps, made of who-knows-what-kinda-plastic. That plastic might
well be affected by the Liquid Wrench Super-Lubricant that I had to use
last night and eventually melt, gumming up the fan again. Frankly, I can't
believe HP did not put in some kind of airflow detector. I think I'm going
to install a simple vane-triggered optoisolator; there's plenty of room
there. I consider such an add-on alarm to be fairly critical for a piece
of test equipment of such vintage that replacement parts may be difficult
to find. When it was new, no worries: order from HP. But I found absolute
NO parts for 8640s on xXxx last night  ;o\  ;o\  ;o\

Thanks,
Steve K0XP