On 9/13/2014 2:55 PM, David davidwhess@... [TekScopes] wrote:
U510 is part number 155-0022-00. I do not understand the 156-022 (or M36)
notation on the schematic but I have seen it and other notations like it before.
155-0022-00 is a low frequency (100+ MHz although the 7704A gets 200 MHz out of
it) channel switch meaning that it multiplexes two differential voltage inputs
into one differential current output. It can be used to select between two
different channels, to add two channel together, as a transconductance
amplifier, or as a paraphase amplifier.
In 1988 during the production of the 2230, it was replaced with the 234-0408-20
which is pin and function compatible but requires different biasing to prevent
oscillation. The 155-0022-00 is common through almost all of the 7000 series
starting in 1969 with the 7504 excluding maybe some early models for which I
have no service documentation and the 7103/7104.
I do not know if any of the late 7000 series starting about 1988 switched to the
234-0408-20. The change notices I have for the 7844, 7854, 7904A, and 7934 do
not show the 234-04-8-20 being used (or I missed it) so I assume Tektronix had a
bunch in reserve and saved them for the instruments that they did not want to do
any redesign on.
Documentation on the 155-0022-00:
magnet:?xt=urn:btih:4DF792045B09CCF6B64AE613A731C2F01A142997
David,
Thanks for the info! Great stuff.
I think the URL you posted didn't quite get everything cut and pasted.
Mark
