Topics

Knob and help.

James R. Bartlett
 

Greetings to the group,
Regular reader but seldom poster needs help.
I am working on a 475 at the moment.
I am in need of a vertical sensitivity knob as the lettering on the Channel
2
one is very badly worn. Anyone have a spare one?
Also have a problem with the voltage indication changing on the Channel
knob.
When using a x10 probe sometimes it will not switch to the x10 lamp.
moving the probe around at the BNC connector sometimes it comes on, Probes
are mainly Tek ones
Some switchable others are fixed x10.
any thoughts ?
Many thanks
Jim
Ei2BB

Tom Gardner
 

When I had a 475 with missing V/div legend, I

* created my own legend
* printed it on transparent plastic
* used UHU "rubber solution glue" to stick it behind the plastic on the knob

Send me an email if you want the files I used for the legend

On 05/02/20 11:04, James R. Bartlett wrote:
Greetings to the group,
Regular reader but seldom poster needs help.
I am working on a 475 at the moment.
I am in need of a vertical sensitivity knob as the lettering on the Channel
2
one is very badly worn. Anyone have a spare one?
Also have a problem with the voltage indication changing on the Channel
knob.
When using a x10 probe sometimes it will not switch to the x10 lamp.
moving the probe around at the BNC connector sometimes it comes on, Probes
are mainly Tek ones
Some switchable others are fixed x10.
any thoughts ?
Many thanks
Jim
Ei2BB

Colin Herbert
 

Hi,

If you are referring to the Volts/Div knobs, then it is possible to repair the lettering on them. I did it some time ago with a knob on a 468; those knobs are unobtainium because of the extra positions and black background. I think I used a gel-pen.

With regard to the lamps behind the knob skirts which light up the appropriate settings for X1 and X10 probes, to begin with, the probe must have the sensor pin to contact the extra ring on BNC connector. It can be checked that the switching and bulbs are OK by connecting between the extra ring and ground with an 11 k ohm resistor. If this doesn't work, there is a possible broken connection inside, but space is limited in there and it isn't easy to access the input BNC connectors. I also recall that the lamps will not be lit unless the appropriate channel is selected to be active.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of James R. Bartlett
Sent: 05 February 2020 11:05
To: Tekscopes@groups.io
Subject: [TekScopes] Knob and help.

Greetings to the group,
Regular reader but seldom poster needs help.
I am working on a 475 at the moment.
I am in need of a vertical sensitivity knob as the lettering on the Channel
2
one is very badly worn. Anyone have a spare one?
Also have a problem with the voltage indication changing on the Channel
knob.
When using a x10 probe sometimes it will not switch to the x10 lamp.
moving the probe around at the BNC connector sometimes it comes on, Probes
are mainly Tek ones
Some switchable others are fixed x10.
any thoughts ?
Many thanks
Jim
Ei2BB

James R. Bartlett
 

Thanks Colin.
Ok on the knobs, yes they are pretty scarce. QService are out of stock.
THe probes do have the necessary pin, they are mainly TEK switched x1/x10
It appears to be a poor contact somewhere as they work sometimes.
Thanks for the reply.
regards
Jim


On Wed, 5 Feb 2020 at 13:17, Colin Herbert via Groups.Io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

Hi,

If you are referring to the Volts/Div knobs, then it is possible to
repair the lettering on them. I did it some time ago with a knob on a 468;
those knobs are unobtainium because of the extra positions and black
background. I think I used a gel-pen.

With regard to the lamps behind the knob skirts which light up the
appropriate settings for X1 and X10 probes, to begin with, the probe must
have the sensor pin to contact the extra ring on BNC connector. It can be
checked that the switching and bulbs are OK by connecting between the extra
ring and ground with an 11 k ohm resistor. If this doesn't work, there is a
possible broken connection inside, but space is limited in there and it
isn't easy to access the input BNC connectors. I also recall that the lamps
will not be lit unless the appropriate channel is selected to be active.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of James
R. Bartlett
Sent: 05 February 2020 11:05
To: Tekscopes@groups.io
Subject: [TekScopes] Knob and help.

Greetings to the group,
Regular reader but seldom poster needs help.
I am working on a 475 at the moment.
I am in need of a vertical sensitivity knob as the lettering on the Channel
2
one is very badly worn. Anyone have a spare one?
Also have a problem with the voltage indication changing on the Channel
knob.
When using a x10 probe sometimes it will not switch to the x10 lamp.
moving the probe around at the BNC connector sometimes it comes on, Probes
are mainly Tek ones
Some switchable others are fixed x10.
any thoughts ?
Many thanks
Jim
Ei2BB







James R. Bartlett
 

Thanks Tom,.
I would like to see the files if it is not too much trouble.
Appreciate the reply and the offer.
Be good to get a good knob or fix up the other one.
Thanks again

Regards
Jim

On Wed, 5 Feb 2020 at 13:03, Tom Gardner <tggzzz@...> wrote:

When I had a 475 with missing V/div legend, I

* created my own legend
* printed it on transparent plastic
* used UHU "rubber solution glue" to stick it behind the plastic on the
knob

Send me an email if you want the files I used for the legend


On 05/02/20 11:04, James R. Bartlett wrote:
Greetings to the group,
Regular reader but seldom poster needs help.
I am working on a 475 at the moment.
I am in need of a vertical sensitivity knob as the lettering on the
Channel
2
one is very badly worn. Anyone have a spare one?
Also have a problem with the voltage indication changing on the Channel
knob.
When using a x10 probe sometimes it will not switch to the x10 lamp.
moving the probe around at the BNC connector sometimes it comes on,
Probes
are mainly Tek ones
Some switchable others are fixed x10.
any thoughts ?
Many thanks
Jim
Ei2BB