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Searching for Tektronix "impeller" vs. "fan", I finally found a picture of
the collet:



That makes sense to me now. Still unsure how turning the screw damages
the collet (presuming the fingers stick to the tapered ID of the impeller
and a twisting motion breaks them) but I'm guessing I'll find out soon
enough.

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "Barry" <n4buq@...>
To: [email protected]
Sent: Monday, August 5, 2019 9:12:01 AM
Subject: Re: [TekScopes] 2445 LVPS Issues

Okay, Chuck. I presumed it was a collet but wasn't sure how to release

it.

Unfortunately, I did turn the screw some in a CCW direction and then back
again so it sounds like I may have damaged the collet. Ugh! Too

tempting

and the manual doesn't give any caveats regarding that (only states not

to

remove the nut which I can't really see what that would hurt either but,
perhaps, because it might bind on the slotted burrs and cause the screw

to

turn). If I can get the impeller off, I'll see what kind of damage I may
have caused. The impellers are still available but I'm guessing the

collet

isn't.

Thanks again,
Barry - N4BUQ

----- Original Message -----

From: "Chuck Harris" <cfharris@...>
To: [email protected]
Sent: Monday, August 5, 2019 8:25:19 AM
Subject: Re: [TekScopes] 2445 LVPS Issues

It is easy:

Put a screwdriver in the slot of the screw, and use a wrench to
turn the nut against the screw (DON't LET THE SCREW TURN!!!)

Back off the nut until it is flush with the slot, and give the
nut a light tap with a hammer. It will move into the squirrel
cage a little bit, and then the squirrel cage can be pulled off.

If you let the screw turn relative to the squirrel cage, it will
destroy the delicate plastic collet... you don't want to do that!

-Chuck Harris

n4buq wrote:

Got everything removed except the fan. Any hints/tricks to getting

that

off? Loosened the nut but the fan blade won't budge and I don't

want to

pull any harder unless it is recommended. I have a feeling that's

some

kind of collet and perhaps pressure on the slotted screw would

release it

but just don't know.

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "Barry" <n4buq@...>
To: [email protected]
Sent: Saturday, August 3, 2019 9:30:54 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

And there, on page 6-25, is the complete process spelled out very
neatly.
Just didn't expect that.

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "n4buq" <n4buq@...>
To: [email protected]
Sent: Saturday, August 3, 2019 9:03:44 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

I didn't realize the SM would go into detail on board removal. I

will

read
up on it there.

Thanks for the tip on the incorrect silkscreen too.

Thanks,
Barry - N4BUQ

----- Original Message -----

From: "Tom Gardner" <tggzzz@...>
To: [email protected]
Sent: Saturday, August 3, 2019 7:10:03 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

The service manual is quite specific on how to remove the various
boards.
It
isn't difficult, if follow instructions.

The manual is available at the usual places, e.g. tekwiki.

Be aware that on some of the 24x5* series the manual and silk

screen

show
two
caps swapped. So when recapping, remove and replace a single

capacitor

before
moving on to the next; don't remove them all and then start

replacing

them.


On 04/08/19 00:13, n4buq wrote:

I was using my 2445 today when I heard a strange sort of thump

noise

coming
from inside the scope after which I started smelling a burning

odor.

I
had a few pieces of gear powered up at the time but quickly could
tell
the
smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is

coming

from
the LVPS board(s) but am a bit stumped at how to get those two

boards

out.
I'm pretty sure the top ribbon cable needs to come off but don't
quite
see how to get the large plastic cover off of the area where the

main

filter caps are.

Looking at some of the smaller caps, they appear to be leaning

due to

(I'm
guessing) bulging at the circuit board end but not sure exactly

what

overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those
boards?
If not, could someone provide a couple of hints to get me

started?

Thanks,
Barry - N4BUQ