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Blanking has nothing to do with the vertical lines between a square
wave. You see the rise time of the square wave. This is not a bad thing.
If the trace has reached the far left of the screen the sawtooth jumps
back to zero and the trace has to start at the rifgt again. In the mean
time you do not want to see it return so a blancking mechanism is added.
(there are several ways) This makes the trace invisible so you only see
the trace from left to right.

The problems you write sound to me like they are in the HV.

Op zondag 27-06-2010 om 06:43 uur [tijdzone +0000], schreef warren:

Thanks. I checked all of the power supply voltages (except the HV) and
they were all spot on and stable. I will borrow an HV probe and check
the high voltages. Occasionally there are indications of a blanking
problem: the square waves have faint lines connecting the tops and
bottom. I don't think this is a triggering problem.

wn

--- In TekScopes@..., fredschneider@ wrote:

Leaking hv caps or power supply caps. At least that gave the same

sort of problem at a philips I repaired. On a 465 I had a almost the
same problem but there it was only a cap in the powersupply. One of
those big ones.

Fred

-origineel bericht-
Onderwerp: Re: [TekScopes] Re: Some problems with recently acquired

465

Van: Pete Burbank <nv4v@>
Datum: 26-06-2010 18:29

warren wrote:

Thanks, Tom. Do you have any idea why the intensity is unstable?

I

notice that when the unit is first turned on and the trace is dim,

it

flickers a fair bit. The flickering eventually goes away and

usually,

after a sufficiently long time, the intensity gets very high, no
matter the setting of the knob. I wouldn't expect this to be

fixable

by re-calibrating the scope.

Thanks again.

Warren

--- In TekScopes@... <mailto:TekScopes%

40yahoogroups.com>,

"Tom Miller" <tmiller@> wrote:

Hi Warren,

I would suggest that you print out the calibration section of

the

manual and go

through the adjustments procedure step by step. it starts out

with

setting and

checking the power supply voltages. There is a part that deals

with

setting the

grid bias correctly.

Then do pay attention to the vertical adjustments. You will need

a

pulse generator

and a signal generator to do it right.


Good luck,
Tom




----- Original Message -----
From: warren
To: TekScopes@... <mailto:TekScopes%

40yahoogroups.com>

Sent: Friday, June 25, 2010 9:51 PM
Subject: [TekScopes] Some problems with recently acquired 465



Hello,

I am new to this group but not to Tek scopes - I have used a

large

variety of them since I was a graduate student in the late 60s. I
recently retired and purchased a used 465 to help with some

projects I

am working on. It was from a local person who works for the large
local software company and was sold at a good price. At his house,

I

noticed that the display was very bright and couldn't be turned

down

very much (it had been on for some time before I arrived). We

opened

the cabinet and turned down the bias pot in the CRT power supply
section and this seemed to solve the problem.

Unfortunately, the problem re-occurs from time to time, usually

when

the scope has been on for a while. The trace focus is pretty good

for

a 465 with little blooming at high intensity (similar to the 475 I

had

in my lab and, of course, not as good as our old 453).

A second problem is the presence of a lot of overshoot on the

leading edge of the calibration square wave (with or without a

probe,

which has been adjusted). This only happens at certain

sensitivity

settings and seems to occur in both channels (but at different

settings).

Any help would be much appreciated. I have the pdf of the

manuals,

which are a bit difficult to use in that form (I have printed some

of

it out).

Thanks!

Warren Nagourney

Hi Warren,

Have you tried contact cleaner on the various pots that affect
brightness? I have had good luck with the Caig products.
Regards,
Pete ....NV4V

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