There are a lot of components out there that require a pretty good “seal” on the package to keep out the atmosphere. Back in the day, some folks did a better job on packages than others. That said, they all probably leak at some rate. Get enough air in this part (like a vacuum sealed crystal) and you see a big impact. Get enough moisture in by this or that transistor, stuff corrodes, specs change. Have this or that brand of memory chip from “those years" and the moisture pretty much kills them dead X years later.

Bob

On Dec 21, 2023, at 10:43 AM, Ray Fantini <[email protected]> wrote:

I spent a lot of time working on GRC-106 sets, one of the highest failure rate items 1A3 frequency standard. The 5 MHz oscillator just stops oscillating, no bad components and just doing regular VOM checks of the transistors and they look good.
They use a couple 2N706 NPN silicon devices, one as an oscillator and the second as a buffer. I tried some generic replacements but no love there. Wonder if I need to buy something for reading gain and start looking at that? The data sheet for the 2N706 tells me that the HEF should be 20
What are you using to see HEF?

Ray F/KA3EKH
______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html