[time-nuts] HP 5060A option 004

[Chuck Norton]

Hi Marc, sorry I forgot to mention about the option 004. When the 5060 was being built, there were no high performance tubes as such. Even when the 5061A was originally released, there wasn't one available for it either. The option 004 tube came along later. Because the tube connections were essentially the same, you could install an option 004 high performance tube in the 5060A and get better performance out of your old unit. This was done on a number of them and you had to do some modifications to get them to work correctly...ie the degauss coil connections. It wasn't a simple "drop in" the first time. You could of course install the tube and not the degauss but you would be losing some of your performance enhancements if you did. At quite a cost increase too.
    One thing you would want to be cautious of if you find the tube is indeed dead. The early tubes used an AC heater circuit that produced an audible whine. The later tubes were designed for a DC heater circuit and required a completely different heater module. I don't believe one was ever made for the 5060A. HP would not even warranty a DC tube that got installed into a unit with an AC heater circuit. This was true whether it was a high performance tube or not. I don't know if it was a serious problem or if HP was just covering their bases in case the unit wouldn't quite meet all of it's specs with the DC tube.
    I have a number of the older manuals but do not have the means to do a pdf scan on them to make them available to the rest of the group. I have the 5060A, 5061A, 5061B, 5062C, and the 5065A rubidium. Unfortunately, I haven't had the time to make any copies of them, much less scan them since it takes about 2 hours each. Unfortunately, the machines do not like the pages that have been hole punched so you have to feed them in by hand. There were many versions of some of these manuals so you want to find one that is as close to your serial numbers prefix, (without being below the number) as you can.

Chuck Norton
Frequency Standards & Services