7603 Graticule Intensity Off Switch: S102


 

I need help locating S102, Readout Intensity control On/Off switch on the
7603.
I have probably owned or used at least 6 to 8 7603s and until now I never
knew there was an on/off switch for the readout but there it is in the
schematic.
If you look at the 1984 7603 "Calibrator and Front Panel Switching"
schematic #7, switch S102 is located in the upper left corner of the
schematic right next to R102B. R102"B" is the 2nd pot on the
Intensity/Readout dual potentiometer. The first pot is R102"A" which
controls the beam Intensity. S102 is clearly shown and its purpose is
stated: "Readout Off".

The part number, R102B and S102, indicate these parts are associated with
the other components of the A2 Logic Board such as the R102A Intensity
control which is located on the lower left of the "Logic" schematic #2.

Mysteriously the S102 switch is missing from the parts list, although there
is a listing for "R102A,B" which makes no mention of the switch. The
description for R102A/B says RES.,VAR,NONWIR:5K OHM X 5K OHM,20%,1W

The parts list suggests to me there must have been some 7603s, at least in
the early days, that had an on/off switch for the readout. I wonder if this
was because Tek was not sure that their customers would want on-screen
readout information displayed on the CRT? Does anybody have a 7603 with an
Off switch for the on-screen readout or does anyone remember using a 7603
with one?

Remember that HP, in their famous Foxtail Ad mocked Tek's new 7000 series
product line for all the expensive unnecessary features their scopes had
such as the on-screen readout. The ad I am referring to is at
https://groups.io/g/TekScopes/files/HP183A%20Foxtail%20Ad%20vs%207KSeries.pd
f
In retrospect it is unbecoming of HP that they ever allowed something like
this to be printed. 2 years after this ad appeared Tek was the acknowledge
leader in oscilloscopes and HP never caught up to them. Tek had the last
laugh because many of those features HP mocked helped to make the 7000
series a huge success.

Dennis Tillman W7pF


Dan G
 

Is this not the switch that is integrated into the READOUT INTENSITY pot, and
activated by turning the pot fully couter-clockwise into detent?

Both of my 7603 mainframes have it (they are late serial numbers), as do
both of my 7623A units (one early, one late serial number). The 7854
READOUT pot also has a similar feature.

This switch is very useful when observing signals whose trigger rate is
close to the time-sharing rate of the read-out system, as it can be used
to remove the somewhat distracting beam intensity modulation.


dan


Eric
 

On mine there is a pot/switch combo on the front of the scope built in to intensity, fully counter clockwise there is the click of a switch and the "noise in the trace associated with the readout dead times vanishes.
It is the same on my Early and late model 7603's
Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Dan G
Sent: Sunday, May 30, 2021 9:52 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7603 Graticule Intensity Off Switch: S102

Is this not the switch that is integrated into the READOUT INTENSITY pot, and activated by turning the pot fully couter-clockwise into detent?

Both of my 7603 mainframes have it (they are late serial numbers), as do both of my 7623A units (one early, one late serial number). The 7854 READOUT pot also has a similar feature.

This switch is very useful when observing signals whose trigger rate is close to the time-sharing rate of the read-out system, as it can be used to remove the somewhat distracting beam intensity modulation.


dan


 

Mystery solved. I found out where it is and how it works. The switch is on
the end of the dual pot. It does not have a "detent" or mechanism to provide
tactile feedback when the switch shuts off the readout. Instead, as the pot
it turned fully CCW, the switch disengages the voltage from the wiper which
guarantees the readout is completely off. Without some kind of tactile
feedback I was not aware of the switch at all. But I confirmed the voltage
from the wiper goes through that switch and from there to the on-screen
readout board.

Dennis Tillman W7pF
_____________________________________________
From: Dennis Tillman W7pF [mailto:dennis@ridesoft.com]
Sent: Sunday, May 30, 2021 6:13 PM
To: TekScopes@groups.io <mailto:TekScopes@groups.io>
Subject: 7603 Graticule Intensity Off Switch: S102


I need help locating S102, Readout Intensity control On/Off switch on the
7603.
I have probably owned or used at least 6 to 8 7603s and until now I never
knew there was an on/off switch for the readout but there it is in the
schematic.
If you look at the 1984 7603 "Calibrator and Front Panel Switching"
schematic #7, switch S102 is located in the upper left corner of the
schematic right next to R102B. R102"B" is the 2nd pot on the
Intensity/Readout dual potentiometer. The first pot is R102"A" which
controls the beam Intensity. S102 is clearly shown and its purpose is
stated: "Readout Off".

The part number, R102B and S102, indicate these parts are associated with
the other components of the A2 Logic Board such as the R102A Intensity
control which is located on the lower left of the "Logic" schematic #2.

Mysteriously the S102 switch is missing from the parts list, although there
is a listing for "R102A,B" which makes no mention of the switch. The
description for R102A/B says RES.,VAR,NONWIR:5K OHM X 5K OHM,20%,1W

The parts list suggests to me there must have been some 7603s, at least in
the early days, that had an on/off switch for the readout. I wonder if this
was because Tek was not sure that their customers would want on-screen
readout information displayed on the CRT? Does anybody have a 7603 with an
Off switch for the on-screen readout or does anyone remember using a 7603
with one?

Remember that HP, in their famous Foxtail Ad mocked Tek's new 7000 series
product line for all the expensive unnecessary features their scopes had
such as the on-screen readout. The ad I am referring to is at
https://groups.io/g/TekScopes/files/HP183A%20Foxtail%20Ad%20vs%207KSeries.pd
f
In retrospect it is unbecoming of HP that they ever allowed something like
this to be printed. 2 years after this ad appeared Tek was the acknowledge
leader in oscilloscopes and HP never caught up to them. Tek had the last
laugh because many of those features HP mocked helped to make the 7000
series a huge success.

Dennis Tillman W7pF


Michael W. Lynch
 

On Mon, May 31, 2021 at 07:57 AM, Dennis Tillman W7pF wrote:


tactile feedback when the switch shuts off the readout. Instead, as the pot
I have a 7603 and a 7633, both have the switch and both of mine have a detent at the full CCW "off" position.

--
Michael Lynch
Dardanelle, AR


Michael W. Lynch
 

Also, Just checked my 7623A and it is the same, Readout Pot has a switch with detent all the way CCW in "off" position.,

--
Michael Lynch
Dardanelle, AR


 

Hi Eric et al,
Strange! I have three 7603s and NONE of them have a detent at the full CCW position. They just stop rotating at that point.
Thanks for explaining to me that the switch allows the scope to trigger as often as possible rather than have to interleave on-screen readout information in between traces. That is a good reason to have an off position.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: Sunday, May 30, 2021 7:08 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7603 Graticule Intensity Off Switch: S102

On mine there is a pot/switch combo on the front of the scope built in to intensity, fully counter clockwise there is the click of a switch and the "noise in the trace associated with the readout dead times vanishes.
It is the same on my Early and late model 7603's Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Dan G
Sent: Sunday, May 30, 2021 9:52 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7603 Graticule Intensity Off Switch: S102

Is this not the switch that is integrated into the READOUT INTENSITY pot, and activated by turning the pot fully couter-clockwise into detent?

Both of my 7603 mainframes have it (they are late serial numbers), as do both of my 7623A units (one early, one late serial number). The 7854 READOUT pot also has a similar feature.

This switch is very useful when observing signals whose trigger rate is close to the time-sharing rate of the read-out system, as it can be used to remove the somewhat distracting beam intensity modulation.


dan













--
Dennis Tillman W7pF
TekScopes Moderator


tinkera123
 

I have 3 without detent ..... 1 with detent ...

--
Cheers,
Ian,
Melbourne, Australia


Jordan
 

I have a 7603, 7613 and 7633, and all of them have the readout switch, although on the 13 and the 33 the switch takes a lot of torque to turn off...