Tektronix 2213 dim trace
 

I have a Tek 2213 in great condition, but the trace is very dim. It
is an old scope from a tv station, they may have just left it on all
day, otherwise it doesn't seem to have any use on it at all. I know
this is a common problem in older scopes, but I've never actually
understood the reason. The phosphors on the crt still glow well, i.e.
if you press beam find and concentrate the trace it's fine. Is this
just a high voltage problem, or is it just the end of the CRT's life?
Filament in the CRT going bad? HV section failing? I know this
happens quite often, but I never understood why. Could someone give
me some expert advice, help educate the younger generation? I
apologize for the simplicity of this question, I just wanted to get to
the bottom of this directly instead of going off of what I've "heard".

Thanks for reading,
Steve

You can look for the CRT bias adjustment, and see if there is able to be
increased. But, if the scope has a lot of hours on it, the CRT is most
likely weak.

If you look around, maybe you can find another one like yours that is a
scrapper, but the CRT is good. Or, if the scope is worth it for you, you can
call Tek to see if a new CRT is still available. They are however, fairly
expensive to buy new, but much cheaper than a new scope.

--

JANA
_____


steve wrote in message ...
I have a Tek 2213 in great condition, but the trace is very dim. It
is an old scope from a tv station, they may have just left it on all
day, otherwise it doesn't seem to have any use on it at all. I know
this is a common problem in older scopes, but I've never actually
understood the reason. The phosphors on the crt still glow well, i.e.
if you press beam find and concentrate the trace it's fine. Is this
just a high voltage problem, or is it just the end of the CRT's life?
Filament in the CRT going bad? HV section failing? I know this
happens quite often, but I never understood why. Could someone give
me some expert advice, help educate the younger generation? I
apologize for the simplicity of this question, I just wanted to get to
the bottom of this directly instead of going off of what I've "heard".

Thanks for reading,
Steve

On Sun, 24 Apr 2005 22:02:40 -0400, "JANA" wrote:

You can look for the CRT bias adjustment, and see if there is able to be
increased. But, if the scope has a lot of hours on it, the CRT is most
likely weak.

If you look around, maybe you can find another one like yours that is a
scrapper, but the CRT is good. Or, if the scope is worth it for you, you can
call Tek to see if a new CRT is still available. They are however, fairly
expensive to buy new, but much cheaper than a new scope.

With the bias all the way up, it was still too dim. Thanks for the
reply, that's what I figured.

Thanks again,
Steve

But if the beam find function results in a bright trace, shouldn't that
mean the CRT is fine?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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"JANA" writes:

You can look for the CRT bias adjustment, and see if there is able to be
increased. But, if the scope has a lot of hours on it, the CRT is most
likely weak.

If you look around, maybe you can find another one like yours that is a
scrapper, but the CRT is good. Or, if the scope is worth it for you, you can
call Tek to see if a new CRT is still available. They are however, fairly
expensive to buy new, but much cheaper than a new scope.

--

JANA
_____


steve wrote in message ...
I have a Tek 2213 in great condition, but the trace is very dim. It
is an old scope from a tv station, they may have just left it on all
day, otherwise it doesn't seem to have any use on it at all. I know
this is a common problem in older scopes, but I've never actually
understood the reason. The phosphors on the crt still glow well, i.e.
if you press beam find and concentrate the trace it's fine. Is this
just a high voltage problem, or is it just the end of the CRT's life?
Filament in the CRT going bad? HV section failing? I know this
happens quite often, but I never understood why. Could someone give
me some expert advice, help educate the younger generation? I
apologize for the simplicity of this question, I just wanted to get to
the bottom of this directly instead of going off of what I've "heard".

Thanks for reading,
Steve

Doesn't the beam finder function, sort of concentrate the beam to a small
area on the screen, and thus less spread of the beam on the screen surface?


--

JANA
_____


"Sam Goldwasser" wrote in message
...
But if the beam find function results in a bright trace, shouldn't that
mean the CRT is fine?

--- sam | Sci.Electronics.Repair FAQ Mirror:
http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the
excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

"JANA" writes:

You can look for the CRT bias adjustment, and see if there is able to be
increased. But, if the scope has a lot of hours on it, the CRT is most
likely weak.

If you look around, maybe you can find another one like yours that is a
scrapper, but the CRT is good. Or, if the scope is worth it for you, you
can
call Tek to see if a new CRT is still available. They are however, fairly
expensive to buy new, but much cheaper than a new scope.

--

JANA
_____


steve wrote in message
...
I have a Tek 2213 in great condition, but the trace is very dim. It
is an old scope from a tv station, they may have just left it on all
day, otherwise it doesn't seem to have any use on it at all. I know
this is a common problem in older scopes, but I've never actually
understood the reason. The phosphors on the crt still glow well, i.e.
if you press beam find and concentrate the trace it's fine. Is this
just a high voltage problem, or is it just the end of the CRT's life?
Filament in the CRT going bad? HV section failing? I know this
happens quite often, but I never understood why. Could someone give
me some expert advice, help educate the younger generation? I
apologize for the simplicity of this question, I just wanted to get to
the bottom of this directly instead of going off of what I've "heard".

Thanks for reading,
Steve

"JANA" writes:

Doesn't the beam finder function, sort of concentrate the beam to a small
area on the screen, and thus less spread of the beam on the screen surface?

Sure, probably 1/2 in both X and Y. So, it would be much brighter. But I
got the impression - perhaps not valid - that the appearance was normal
for the beam finder but maybe he just meant the brightness was then adequate.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
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steve wrote:

On Sun, 24 Apr 2005 22:02:40 -0400, "JANA" wrote:

You can look for the CRT bias adjustment, and see if there is able to be
increased. But, if the scope has a lot of hours on it, the CRT is most
likely weak.

If you look around, maybe you can find another one like yours that is a
scrapper, but the CRT is good. Or, if the scope is worth it for you, you can
call Tek to see if a new CRT is still available. They are however, fairly
expensive to buy new, but much cheaper than a new scope.

With the bias all the way up, it was still too dim. Thanks for the
reply, that's what I figured.

Thanks again,
Steve

Have you checked the resistors in the brightness and contrast
circuits?
--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

"Michael A. Terrell" wrote in
:

steve wrote:

On Sun, 24 Apr 2005 22:02:40 -0400, "JANA" wrote:

You can look for the CRT bias adjustment, and see if there is able
to be increased. But, if the scope has a lot of hours on it, the CRT
is most likely weak.

If you look around, maybe you can find another one like yours that
is a scrapper, but the CRT is good. Or, if the scope is worth it for
you, you can call Tek to see if a new CRT is still available. They
are however, fairly expensive to buy new, but much cheaper than a
new scope.

With the bias all the way up, it was still too dim. Thanks for the
reply, that's what I figured.

Thanks again,
Steve

Have you checked the resistors in the brightness and contrast
circuits?

Early 2213/15 scopes had a problem with a little too high CRT filament
voltage,drastically shortening the CRT's life,so a "mandatory" mod was
generated that removed one half-turn off the HV transformer filament
winding.This "mandatory" mod meant that letters were sent out to known
owners and any 2213/15 that cme into a TEK field office was modded and a
mod sticker placed on the back.IIRC,the HV xfmr should have a -01 suffix if
made -after- the mod came out.
The sticker identifying a modded scope should say "M50226",and the serial
number range was B010100 to B029389 ,and 200001-206198.

--
Jim Yanik
jyanik
at
kua.net

On 25 Apr 2005 09:14:47 -0400, Sam Goldwasser
wrote:

But if the beam find function results in a bright trace, shouldn't that
mean the CRT is fine?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
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snip


Sorry, I should have specified. I just meant the latter, that the
brightness was just adequate. The Ser # is B021862, and there is no
sticker or note on the back, besides what looks like a hand-written
q.c. sticker, it says BES, S 6/28, I didn't open up the power supply
cage so I don't know if the xformer has the -01 suffix. I would love
to get this 'scope running if possible and not too expensive. My only
other two are both on their last legs, a T935a and a 422. What about
this one on ebay (item # 7510403355)? Does that screen problem look
like a damaged CRT, or possibly something else? Thanks for all the
great replies, I'd love to get this one back up again.

Steve

steve writes:

On 25 Apr 2005 09:14:47 -0400, Sam Goldwasser
wrote:

But if the beam find function results in a bright trace, shouldn't that
mean the CRT is fine?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

snip


Sorry, I should have specified. I just meant the latter, that the
brightness was just adequate. The Ser # is B021862, and there is no
sticker or note on the back, besides what looks like a hand-written
q.c. sticker, it says BES, S 6/28, I didn't open up the power supply
cage so I don't know if the xformer has the -01 suffix. I would love
to get this 'scope running if possible and not too expensive. My only
other two are both on their last legs, a T935a and a 422. What about
this one on ebay (item # 7510403355)? Does that screen problem look
like a damaged CRT, or possibly something else? Thanks for all the
great replies, I'd love to get this one back up again.

It's possible that the only problem is that one of the H-plate wires fell off,
a power supply is bad, or some other circuit problem. I would not guess a
bad CRT but the Tek experts here can be more definitive.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.