Tektronix 7S11 question

[David C. Partridge]

I already asked this in the TekScopes list on Yahoo, but so far no
one has stepped up to answer it there.

One of my 7S11s (SN B125nnn) appears to largely match the description
in the military service manual I downloaded from BAMA (even though it
is clearly a later unit than covered by that manual as the vertical
board is level 01 revision).

The other one has serial B102nnn, and has a different "dot response"
control. The pot has a switch detent in the fully CCW position and
there's a 10 turn pot mounted on a small piece of matrix board just
behind the control. There is an EC wire running from the matrix
board to the lower side of the toroid near the rear of the Vertical
board. I *think* that when the pot is turned into the detent, the
switch is actuated and the dot response setting is taken from the rear
mounted pot rather than the front panel control.

This particular unit was for many years the property of Tektronix
Sweden, and still has Tektronix Asset stickers.

Clearly this change will have an impact on the calibration procedure,
so I have a couple of questions:

1) Is this a normal production or service modification, or a "special"?

2) Would it be likely to be covered in the commercial manual? If so
are there any specific manual revision dates that I would need to make
sure that this is covered?

Thanks
Dave Partridge (remove xwy from replyto email address)

 

[Jim Yanik]

I already asked this in the TekScopes list on Yahoo, but so far no
one has stepped up to answer it there.

One of my 7S11s (SN B125nnn) appears to largely match the description
in the military service manual I downloaded from BAMA (even though it
is clearly a later unit than covered by that manual as the vertical
board is level 01 revision).

The other one has serial B102nnn, and has a different "dot response"
control. The pot has a switch detent in the fully CCW position and
there's a 10 turn pot mounted on a small piece of matrix board just
behind the control. There is an EC wire running from the matrix
board to the lower side of the toroid near the rear of the Vertical
board. I *think* that when the pot is turned into the detent, the
switch is actuated and the dot response setting is taken from the rear
mounted pot rather than the front panel control.

This particular unit was for many years the property of Tektronix
Sweden, and still has Tektronix Asset stickers.

Clearly this change will have an impact on the calibration procedure,
so I have a couple of questions:

1) Is this a normal production or service modification, or a "special"?

2) Would it be likely to be covered in the commercial manual? If so
are there any specific manual revision dates that I would need to make
sure that this is covered?

Thanks
Dave Partridge (remove xwy from replyto email address)

It sounds like a non-TEK mod.
Tek did not use "matrix board" in any official TEK mods.
Now,some Tek-Sweden employee could have installed it on their own.(not TEK
sanctioned,either.) Maybe a tech needed a finer adjustment than he got from
the stock front panel pot.I did that on a SG505 audio generator output
level control while at TEK.

By "matrix board",I'm guessing you mean perforated board,maybe with plated
thru-holes,and not an etched PCB of some sort?

 

[David C. Partridge]

I've found out what this is all about from the previous owner of the
plug-in.

It was a custom modification: The purpose of it was to get a preset Dot
Response setting when calibrating customer's sampling heads.

Turning the switch into the detent results in the dot response setting being
taken from rear 10 turn pot rather than the front panel control as I
suspected.

Dave

 

[Jim Yanik]

I've found out what this is all about from the previous owner of the
plug-in.

It was a custom modification: The purpose of it was to get a preset
Dot Response setting when calibrating customer's sampling heads.

Turning the switch into the detent results in the dot response setting
being taken from rear 10 turn pot rather than the front panel control
as I suspected.

Dave

TEK custom mods will have a modified product foil tag on it so they can
reference the proper documentation.And they did not use perf board for
those mods.

AFAIK,TEK does not do custom mods anymore because they do not want to do
the documentation,nor the custom parts support.

That is the problem with custom mods;others may not know what the mod is
for or what it does,the documentation is lacking,custom parts may not be
available,and cal procedures may be affected.