Simpson and other VOMs do not have enough voltage to exceed the forward
breakdown voltage of a high voltage rectifier which are normally made with
a number of diodes in series. I know the correct pins. I want to comfirm
these are 872 replacement and not some other.

In article , (Scott
Dorsey) wrote:

Tom wrote:
I have what I believe to be six solid-state 872A replacements. They were
made by Motorola and have the part number SDA 188 and date code of 1967.
They have plate cap and 4 pins base with locator pin on side to fit
Johnson socket. They are 3- 3/16 high and a diameter of 1-13/16. Aluminum
can with ceramic base and epoxy filled. I am wondering if anyone has any
data on these to confirm that these are 872 replacement. I have done
several WEB searches but was unable to get any good hits. Thanks Tom

Time to get out the Simpson 260. What base pins connect to the plate,
and in which direction?
--scott