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
Wb6iqd

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
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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

Tom wrote:
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.

If it has the same pinout as the 872, and the has the same series resistance
as the 872, and it has as high a breakdown voltage as the 872, I'd say it's
an 872 replacement. It might not say so in the catalogue but it still is.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Scott Dorsey" wrote in message
...
Tom wrote:
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.

If it has the same pinout as the 872, and the has the same series
resistance
as the 872, and it has as high a breakdown voltage as the 872, I'd say
it's
an 872 replacement. It might not say so in the catalogue but it still is.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Without knowing the device's PIV and current rating,
it would be hard to say what it replaces. The resistance
would be different from a vacuum
or mercury vapor if the replacement is solid state.

I'd try an older Motorola TwoWay shop for advice.
A lot of hams work in them, and one of them might
have first hand experience with the part. Most
Motorola part numbers are a lot longer--the one you
gave doesn't look quite right.

pete