El jueves, 23 de mayo de 2019, 1:13:10 (UTC-4), escribió:
On Wed, 22 May 2019 20:55:03 -0500, Fox's Mercantile
wrote:

On 5/22/19 8:39 PM, John-Del wrote:
On Wednesday, May 22, 2019 at 9:16:45 PM UTC-4, wrote:
This website discusses it, but never really identifies the part. This is
the meter I am working on and I too wondered what the SA1 and SA2 parts
are. I never saw that symbol.

https://www.antiqueradios.com/forums...c.php?t=117824

Schematic on the webpage.



Wild guess: spark gaps for protection.


Despite posting the forum link where they are identified as Surge
Arresters, Tube Guy posted the "what are they?" question over here.

No one on that forum CLEARLY said what they are. Just guesses.....
Guesses are not real answers.....

The first message of the forum link posted by you, clearly stated that the "mistery part" was labeled 39ZR07, and looked like a "disk green cap".

A quick search with Google threw this:

http://www.weisd.com/test/GenericPar...ditid1=39ZR07D

39ZR07D NTE Equvilent NTE1V025 MOV 25V RMS DIA=8.5MM 1.7 JOULES ITM=250A CLAMPING VOLTAGE=80V

https://www.datasheets360.com/part/d...8802698168439/

So it's just a MOV.