Topics

the blue filter slot on 244* scopes

John Ferguson
 

I have 2 2445B's and a 2465.  They have moulded-in grooves in the top of the bezel, but not slots. It appears that the only way I can put a blue filter on one of my scopes is to remove the bezel and install it from the inside.

What am I missing?


john

Chuck Harris
 

The trick.

The filter goes inside of the bezel lips, right tight against the clear
plastic implosion protection screen.

It slides up into a slot and a waiting spring, inside of the top lip
of the bezel, and the combination of gravity and spring pressure holds
it into a shallow groove along the inside of the bottom lip, of the bezel.

To remove the filter, take your fingers, and put some big finger prints
on the center of the filter, as you use your finger's friction to slide
the filter up into the groove with the retaining spring.

While the filter is in the up position, slip a fingernail under the
bottom edge of the filter and pull it towards you... If you don't have
fingernails, stick a business card under the filter's bottom edge, and
then release it. Pull the business card out, and the filter will come
with it.

-Chuck Harris

John Ferguson via Groups.Io wrote:

I have 2 2445B's and a 2465. They have moulded-in grooves in the top of the bezel,
but not slots. It appears that the only way I can put a blue filter on one of my
scopes is to remove the bezel and install it from the inside.

What am I missing?


john

Craig Cramb
 

Installing requires removal of front and carefully installed so finger prints don’t make display dirty. I think Chuck is only talking about removal ,but why not remove the front and not take risk about cracking or scratches to plastic display.

Craig

On Oct 26, 2018, at 12:22 PM, John Ferguson via Groups.Io <jferg977=aol.com@groups.io> wrote:

What am I missing?


john

Chuck Harris
 

No, I am not only talking about removal.

Unless you are working with something way different than the
2465, 2465A, or 2465B, what I said applies to both removal and
installation of the blue filter.

The clear implosion filter is a whole different kettle of
fish, and its careless removal usually results in breaking the
knobs under the CRT when you remove them to remove the bezel...

-Chuck Harris

Craig Cramb wrote:

Installing requires removal of front and carefully installed so finger prints don’t make display dirty. I think Chuck is only talking about removal ,but why not remove the front and not take risk about cracking or scratches to plastic display.

Craig
On Oct 26, 2018, at 12:22 PM, John Ferguson via Groups.Io <jferg977=aol.com@groups.io> wrote:

What am I missing?


john


 

Chuck is 100% correct.  DO NOT REMOVE THE BEZEL to move the blue filter (installing or removing).  Bezel removal requires pulling the knob covers off the knobs below the screen.  This requires skill to do without breaking the tiny fingers that hold the knobs in place.  Besides, it is a nightmare to install the blue filter when the bezel is disassembled because the bezel spring cant be properly compressed when the bezel is removed.  Removing/installing the blue filter is trivial unless something is broken.  Here is the explanation again:
The blue filter is precisely as wide as the screen bezel opening and slightly taller.  There are slots at the top of the screen and the bottom.  The slot at the top has a small bent metal spring and the slot at the bottom is about 2-3 millimeters deep with nothing at the bottom.  To install the blue filter you simply place the top edge of the filter against the screen and slide it up against the spring.  A slight upward force with your finger tips is enough to compress the spring and let the filter slide upward.  Your fingers can then press the filter against the screen and it will drop into the slot at the bottom.  If this doesn't work there is dirt or something in the slots.  Find out why it doesn't work before setting out to "fix" anything.

On ‎Friday‎, ‎October‎ ‎26‎, ‎2018‎ ‎01‎:‎06‎:‎19‎ ‎PM‎ ‎CDT, Chuck Harris <cfharris@...> wrote:

No, I am not only talking about removal.

Unless you are working with something way different than the
2465, 2465A, or 2465B, what I said applies to both removal and
installation of the blue filter.

The clear implosion filter is a whole different kettle of
fish, and its careless removal usually results in breaking the
knobs under the CRT when you remove them to remove the bezel...

-Chuck Harris

Craig Cramb wrote:
Installing requires removal of front and carefully installed so finger prints don’t make display dirty. I think Chuck is only talking about removal ,but why not remove the front and not take risk about cracking or scratches to plastic display.

Craig
On Oct 26, 2018, at 12:22 PM, John Ferguson via Groups.Io <jferg977=aol.com@groups.io> wrote:

What am I missing?


john


 

IF you do need to remove the knobs, I have found that applying some heat from a hot air gun will allow you to pull the knobs off without breaking the internal tabs. I use a hot air rework gun with a small nozzle and set to 100 degrees C.

Regards,
Tom

----- Original Message -----
From: "machineguy59 via Groups.Io" <machineguy59=yahoo.com@groups.io>
To: <TekScopes@groups.io>
Sent: Friday, October 26, 2018 2:39 PM
Subject: Re: [TekScopes] the blue filter slot on 244* scopes


Chuck is 100% correct. DO NOT REMOVE THE BEZEL to move the blue filter (installing or removing). Bezel removal requires pulling the knob covers off the knobs below the screen. This requires skill to do without breaking the tiny fingers that hold the knobs in place. Besides, it is a nightmare to install the blue filter when the bezel is disassembled because the bezel spring cant be properly compressed when the bezel is removed. Removing/installing the blue filter is trivial unless something is broken. Here is the explanation again:
The blue filter is precisely as wide as the screen bezel opening and slightly taller. There are slots at the top of the screen and the bottom. The slot at the top has a small bent metal spring and the slot at the bottom is about 2-3 millimeters deep with nothing at the bottom. To install the blue filter you simply place the top edge of the filter against the screen and slide it up against the spring. A slight upward force with your finger tips is enough to compress the spring and let the filter slide upward. Your fingers can then press the filter against the screen and it will drop into the slot at the bottom. If this doesn't work there is dirt or something in the slots. Find out why it doesn't work before setting out to "fix" anything.

On ‎Friday‎, ‎October‎ ‎26‎, ‎2018‎ ‎01‎:‎06‎:‎19‎ ‎PM‎ ‎CDT, Chuck Harris <cfharris@...> wrote:

No, I am not only talking about removal.

Unless you are working with something way different than the
2465, 2465A, or 2465B, what I said applies to both removal and
installation of the blue filter.

The clear implosion filter is a whole different kettle of
fish, and its careless removal usually results in breaking the
knobs under the CRT when you remove them to remove the bezel...

-Chuck Harris

Craig Cramb wrote:
Installing requires removal of front and carefully installed so finger prints don’t make display dirty. I think Chuck is only talking about removal ,but why not remove the front and not take risk about cracking or scratches to plastic display.

Craig
On Oct 26, 2018, at 12:22 PM, John Ferguson via Groups.Io <jferg977=aol.com@groups.io> wrote:

What am I missing?


john


Chuck Harris
 

Yep! That is one of the "pro tips" for this scope... and it
does a great job... assuming that someone hasn't been there
before you, and uhmmm, "fixed" the knobs he broke.

Epoxy is the worst! Can't get that apart without breaking
the shaft adapter...

-Chuck Harris

Tom Miller wrote:

IF you do need to remove the knobs, I have found that applying some heat from a hot
air gun will allow you to pull the knobs off without breaking the internal tabs. I
use a hot air rework gun with a small nozzle and set to 100 degrees C.

Regards,
Tom

John Ferguson
 

Thanks guys. I hadn't grasped that the filter is installed facing the display and sliding the top up under the bezel and then when the bottom clears the lip of the bezel, easing the bottom down under the lip. I did it the old-fashioned way about 6 moths ago by removing the bezel.  For some reason I had no trouble with the knobs.

Thanks for explaining this to me.

john

tom jobe <tomjobe@...>
 

Thank you everyone, for another fine thread about a common Tektronix scope family problem!
The only thing I can think of to add to the discussion... is that a nice dab of silicon sealant / RTV will hold the 24x5 knobs back on after you break one or more of the clips inside the knobs.
The RTV does not adhere to anything too tightly so the knobs will come off easily the next time you need to remove the front. Then you can pull out the old RTV and put in another dab of RTV to remount the same clip-less knobs again.
tom jobe...

On 10/26/2018 12:09 PM, Chuck Harris wrote:
Yep! That is one of the "pro tips" for this scope... and it
does a great job... assuming that someone hasn't been there
before you, and uhmmm, "fixed" the knobs he broke.

Epoxy is the worst! Can't get that apart without breaking
the shaft adapter...

-Chuck Harris

Tom Miller wrote:
IF you do need to remove the knobs, I have found that applying some heat from a hot
air gun will allow you to pull the knobs off without breaking the internal tabs. I
use a hot air rework gun with a small nozzle and set to 100 degrees C.

Regards,
Tom

Mark Litwack
 

For the 24xx broken internal knob clips problem, I've had good success with 3M #4926 VHB (very high bond) foam tape. A small dot placed on the tip of the shaft extender or all the way on the inside flat area of the knob will hold it. The foam tape is only 15mil thick, so it doesn't make the knob stick out.

Like the RTV, you can pull it off again with minimal force. You can also stick it back on again if the tape it doesn't get mangled, and you don't have to wait for it to cure.