tek 465b scope problem
 

Hi,

I'm relatively new to electronics...
I've got a tek 465b that has been working fine for about 8 months.
The other day without any sort of warning the crt failed to come on
when I started it. It still triggers, but I see nothing even when I
press the beam find button. I also happen to have another 465b from a
sour ebay transaction which has no horiz scan.

Is it beyond the capability of someone like myself to swap the crt
following some careful instructions? I know there are high voltages
involved.

Is it worth it to have a professional do this or should I just forget
about the old scope and consider buying something new? I'm starting
to realize that ebay may not be the best place for scopes...

Any opinions?

Thanks,
aaron

tek 465b scope problem
 

(Aaron Kentucky) writes:

Hi,

I'm relatively new to electronics...
I've got a tek 465b that has been working fine for about 8 months.
The other day without any sort of warning the crt failed to come on
when I started it. It still triggers, but I see nothing even when I
press the beam find button. I also happen to have another 465b from a
sour ebay transaction which has no horiz scan.

Is it beyond the capability of someone like myself to swap the crt
following some careful instructions? I know there are high voltages
involved.

Is it worth it to have a professional do this or should I just forget
about the old scope and consider buying something new? I'm starting
to realize that ebay may not be the best place for scopes...

It's probably not a bad CRT but an electronic problem like the HV power
supply..

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tek 465b scope problem
 

In article ,
says...
It's probably not a bad CRT but an electronic problem like the HV power
supply..

Do you have the service manual? I think I've seen it on eBay for about
ten bucks. There is a pretty detailed troubleshooting flowchart for "no
visible display".

--
Jay Levitt |
Wellesley, MA | Hi!
Faster: jay at jay dot eff-em | Where are we going?
http://www.jay.fm | Why am I in this handbasket?

tek 465b scope problem
 

tek 465b scope problem
 

Hi:

Sorry to hear of your scope trouble ...

1. I got burned 2 for 2 on Ebay scopes

2. I have a Tek 465B and the service manual (I fixed them for a used scope
dealer a few years ago).

I will gladly assist you (walk you through the major tests, or compare readings
from my scope, etc,.

No, the CRT is very simple to swap.

If you are close to PA/OH I also repair scopes, etc., for a very reasonable
fee.

RJ

tek 465b scope problem
 

Jim Yanik wrote in message

Did you hear the hiss/crackle of the HV charging the CRT? If not,the HV may
have failed.

Yes. I also managed to find the manual and am running through the
troubleshooting flowchart now. When I flip it around to slide the
cover off I hear a nice 'jingle jingle.' I'm sure that is not good.

Thanks,
aaron

tek 465b scope problem
 

Thanks for the responses!

Here is some more info after doing some tests. All the low-voltages
check out (I don't have a hv meter.) When I disconnect the power
jumper to the vertical output amp the trace shows with horizontal
scan. This rules out a faulty crt.

Since I have an identical board I swapped it out with the other and
the same thing happens. Furthermore, I discovered that when the top
connector to the vertical deflection plates is disconnected the trace
also shows. This connector is sitting at +54 while the other is at
+16 which seesm to be in violation, but again this happens on both
boards. The delay line into the board is at +225mv and -204mv.

Thanks,
aaron

tek 465b scope problem
 

tek 465b scope problem
 

"Aaron Kentucky" wrote in message
Yes. I also managed to find the manual and am running through the
troubleshooting flowchart now. When I flip it around to slide the
cover off I hear a nice 'jingle jingle.' I'm sure that is not good.

Thanks,
aaron


Yuck, a jingle-jingle often means that a little bit of glass has broken off
one of the internal CRT supports. Those glass support rods are under a bit
of strain, and it doesnt take much to crack a piece off of them. I've seen
this happen a time or two.

What happens then is if you tilt the scope the bits of glass eventually put
a hole or dent in this fragile little metal screen that acts like a
magnifying lens-- then the scope trace goes all fireworksy and the CRT is
useless. Really, really cool to play with, better than a lava lamp, but
mostly useless as a scope.

tek 465b scope problem
 

tek 465b scope problem
 

I don't know if anyone is interested or not but i figure this will
still be good for the archives if someone else has the problem in the
future.

It turned out to be the vertical output amp after all. I tried
swapping them again and this time it worked perfectly! I must have
made a mistake the first time. Anyway, thank you all who responded to
help me out as I'm extremely happy that I got this thing going again
(and got use out of the broken 465b that was collecting dust!!)

On top of all that I learned a great deal about the workings of my
scope.

Thanks!
aaron