Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default what or how to check CRT HV anode wire repair ?

I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did the
job correctly/well ?
Like checking for corona leaks or any other such matters ?

Best method to do these tests

Also i noticed the Aquadag coating on the good CRT is alot more
uneven (bumpy) is there anything that should be done with the
Aquadag ?

Any useful ideas and help appreciated.
robb

  #2   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 1,572
Default what or how to check CRT HV anode wire repair ?


"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did the
job correctly/well ?
Like checking for corona leaks or any other such matters ?

Best method to do these tests

Also i noticed the Aquadag coating on the good CRT is alot more
uneven (bumpy) is there anything that should be done with the
Aquadag ?

Any useful ideas and help appreciated.
robb


Turn it on in a dark room and look for corona, smell for ozone, listen for
sizzling, and pull the plug if anything bursts into flames


  #3   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 88
Default what or how to check CRT HV anode wire repair ?

James Sweet wrote:
"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did the
job correctly/well ?
Like checking for corona leaks or any other such matters ?

Best method to do these tests

Also i noticed the Aquadag coating on the good CRT is alot more
uneven (bumpy) is there anything that should be done with the
Aquadag ?

Any useful ideas and help appreciated.
robb


Turn it on in a dark room and look for corona, smell for ozone, listen for
sizzling, and pull the plug if anything bursts into flames


Ahhh!!! why deny us the pleasure of a nice bonfire?????
(have a video capable phone ready please!)
  #4   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default what or how to check CRT HV anode wire repair ?


"Jim Yanik" wrote in message
...
"robb" wrote in
:

I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did

the
job correctly/well ?


I'd allow a sufficient time for the silicone to cure FULLY.
Otherwise,it becomes a leakage path.

Better to wait too long than too little.
Jim Yanik


Hello Jim,

Thanks for help.

I created a mock up cap and silicon seal on a piece of glass
just after the repair cap and seal so that i could check in 24
hours to see where the mock up was in the curring cycle.

I was planning to wait 24 hours, check the mock up curring and
then see if i should wait another 24.

Thanks for the help ,
robb

  #5   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default what or how to check CRT HV anode wire repair ?


"James Sweet" wrote in message
news:lUJpj.2817$FW3.19@trndny03...

"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did

the
job correctly/well ?


Turn it on in a dark room and look for corona, smell for ozone,

listen for
sizzling, and pull the plug if anything bursts into flames



Haha....
I may eat my soldering iron if it bursts into flames. (after it
cools down... the soldering iron that is)

thanks, i think,
robb



  #6   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default what or how to check CRT HV anode wire repair ?


"Sjouke Burry" wrote in
message ...
James Sweet wrote:
"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did

the
job correctly/well ?

Turn it on in a dark room and look for corona, smell for

ozone, listen for
sizzling, and pull the plug if anything bursts into flames

Ahhh!!! why deny us the pleasure of a nice bonfire?????
(have a video capable phone ready please!)


Ok, so i will start he video camera before i turn it on
the next uTube hit :{
robb
robb

  #7   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default what or how to check CRT HV anode wire repair ?


"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did the
job correctly/well ?
Like checking for corona leaks or any other such matters ?

Best method to do these tests

Also i noticed the Aquadag coating on the good CRT is alot more
uneven (bumpy) is there anything that should be done with the
Aquadag ?

Any useful ideas and help appreciated.
robb


An AM radio nearby can give a good indication of corona discharge. You get a
sort of a 'whining' noise. Breathing on the area with a good "HAAAAA" will
also show up any tendency for corona, which takes place more readily when
the air surrounding any potential discharge site, is made moist. With the AM
radio on, wave a screwdriver around the area. Again, this will provoke any
potential sites, and you should hear it. Eveness of the outer 'dag coating
should not be of any consequence.

Arfa


  #8   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default what or how to check CRT HV anode wire repair ?


"Arfa Daily" wrote in message
...

"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap


An AM radio nearby can give a good indication of corona

discharge. You get a
sort of a 'whining' noise. Breathing on the area with a good

"HAAAAA" will
also show up any tendency for corona, which takes place more

readily when
the air surrounding any potential discharge site, is made

moist.

Hello Arfa,

Thanks for reply.

Breathing with a HAAAAA ? is this going to be one of those the
HAAHAHA, the jokes on me kinda of suggestions ? where my ears
buzz, i see flashes of light and my eyebrow twitches for the rest
of the day.

Sounds suspiciously like one of those suggestions the Senior
engineers give to the new rookies to amuse themselves and the
other senior engineers.


With the AM
radio on, wave a screwdriver around the area. Again, this will

provoke any
potential sites, and you should hear it. Eveness of the outer

'dag coating
should not be of any consequence.

Arfa


as long as it does not provoke a zap on me then i will give it a
try.

Thanks for the help Arfa,
robb


  #9   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default what or how to check CRT HV anode wire repair ?


"robb" wrote in message
...

"Arfa Daily" wrote in message
...

"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap


An AM radio nearby can give a good indication of corona

discharge. You get a
sort of a 'whining' noise. Breathing on the area with a good

"HAAAAA" will
also show up any tendency for corona, which takes place more

readily when
the air surrounding any potential discharge site, is made

moist.

Hello Arfa,

Thanks for reply.

Breathing with a HAAAAA ? is this going to be one of those the
HAAHAHA, the jokes on me kinda of suggestions ? where my ears
buzz, i see flashes of light and my eyebrow twitches for the rest
of the day.

Sounds suspiciously like one of those suggestions the Senior
engineers give to the new rookies to amuse themselves and the
other senior engineers.


No, it's quite genuine. You need to "HAAAA" like a giant sigh, rather than
blow like putting out a candle. This shifts a large volume of slow-moving
and moist air into the area. Any spikes on the soldering or poor insulation
on the HV, will discharge much more readily into moist air, than dry air. It
represents no danger to you, as nothing is going to jump that distance,
unless your 'scope tube has a PDA with about a 100kV on it ...



With the AM
radio on, wave a screwdriver around the area. Again, this will

provoke any
potential sites, and you should hear it.



as long as it does not provoke a zap on me then i will give it a
try.


The metal shaft of a screwdriver with a plastic handle, held in your hand,
will draw a good arc from a high voltage supply, without you feeling a
thing. In the good old days of valve (tube) only TV sets, it was a standard
test to pull an arc from the top caps of the boost rectifier and HOP valves.
Also, from the cap of a DY87 or the wires of an EY86 HV rectifier valve. You
couldn't do it in later sets, because of those new-fangled transistor
things, that would just expire if did anything like that within about 2
yards of them ! Anyway, the point is that if there is anywhere that has a
predisposition to corona discharge, a metal screwdriver blade waved in the
vicinity, will likely help it along. I'm not talking a big long spark
jumping out at you, just some ozone, or maybe a discharge that you can hear.


Trust me ! No dangerous suggestions from this quarter, ever ...


Thanks for the help Arfa,
robb



Arfa


  #10   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 533
Default what or how to check CRT HV anode wire repair ?

Arfa Daily wrote:
snip
Trust me ! No dangerous suggestions from this quarter, ever ...

Thanks for the help Arfa,
robb


Related: Check your car's high tension (spark plug) wires. On a dark
night, away from ambient light; open the hood with engine running.
Leaky HT wires will be readily apparent.

I had an AH Sprite that 'accidentally' introduced me to this technique,
which I've seen published since. I opened the hood for some
reason...blue sparks were dancing all over the engine. I replaced all
the HT leads toute suite....

jak

Arfa




  #11   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 145
Default what or how to check CRT HV anode wire repair ?

Arfa Daily wrote:

The metal shaft of a screwdriver with a plastic handle, held in your
hand, will draw a good arc from a high voltage supply, without you
feeling a thing. In the good old days of valve (tube) only TV sets, it
was a standard test to pull an arc from the top caps of the boost
rectifier and HOP valves. Also, from the cap of a DY87 or the wires of
an EY86 HV rectifier valve.

Trust me ! No dangerous suggestions from this quarter, ever ...

Arfa


This reminds me of an incident many years ago in a TV repair shop.
Several of the engineers had been feeding a mouse and it had become
quite tame, running down the back of the benchtop. Anyway one day
someone managed to zap it with a loose anode cap lead. I'de never seen
a mouse glow blue before.

--
Regards:
Baron.
  #12   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default [Update - Done] what or how to check CRT HV anode wire repair ?

Silicon cured, CRT installed and tested.

Sorry no fireworks or shooting flames

thanks to Arfa, Jim, James, Sjouke etc...for the help.

Installed the new CRT and watched for all the symptoms and signs
people mentioned in the (sci.electronic.$$$$$) groups

No HV problems. But now the scope needs display adjusting to
suit the new CRT.

Problems:
==========
The display is skewed and the intensity and focus are off.

I was not expecting te new CRT to have hyper-intensity troubles.
That is... from no visible trace to oversaturated CRT brightness
is a very small range of knob motion maybe a 1/4-1/3 of he full
turn .

And the focus is very sensitive, touch sensitive ? was not
before.

And the internal probe calibration signal (.5 V @ 1 kHz) produces
a trace with fuzzy band for peaks ( 20 - 30 mV) or so wide. This
was not the case before maybe more like (5 mV ripple before CRT
swap)

So hopefully i can sort these problems out.

thanks for all the safety advice,
robb



"robb" wrote in message
...
I changed the CRT HV anode wire on TEK o'scope by ...
- removing the silicon glued cover/cap
- desolder old anode lead
- clean silicon
- solder new anode lead
- re-silicon the lead cover/cap

Now ? is there any test i should perform to make sure i did the
job correctly/well ?


  #13   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default [Update - Done] what or how to check CRT HV anode wire repair ?


"robb" wrote in message
...
Silicon cured, CRT installed and tested.

Sorry no fireworks or shooting flames

thanks to Arfa, Jim, James, Sjouke etc...for the help.

Installed the new CRT and watched for all the symptoms and signs
people mentioned in the (sci.electronic.$$$$$) groups

No HV problems. But now the scope needs display adjusting to
suit the new CRT.

Problems:
==========
The display is skewed and the intensity and focus are off.

I was not expecting te new CRT to have hyper-intensity troubles.
That is... from no visible trace to oversaturated CRT brightness
is a very small range of knob motion maybe a 1/4-1/3 of he full
turn .

And the focus is very sensitive, touch sensitive ? was not
before.

And the internal probe calibration signal (.5 V @ 1 kHz) produces
a trace with fuzzy band for peaks ( 20 - 30 mV) or so wide. This
was not the case before maybe more like (5 mV ripple before CRT
swap)

So hopefully i can sort these problems out.


It sounds to me like this replacement CRT might not be quite as 'compatible'
as you had hoped ... :-( Maybe that's part of the reason that the PDA lead
was not long enough to fit in your chassis i.e. to stop such a substitution
taking place. As far as the trace being 'skewed' do you mean that it is not
perfectly horizontal, or that it is trapezoidally distorted ? If the former,
then most decent 'scopes have a trace rotation control somewhere. As far as
the brightness / focus issues go, that is likely to be quite difficult to
resolve, and will probably require changes to be made to the component
values in the resistor chains providing the biasing voltages to the various
electrodes. I would suggest that you will not get too far with that, without
having schematics for both the 'scope that you've put the tube in, and the
one that it came out of, so that you can make comparisons of values and
expected voltages. Just as a matter of interest, are the quoted deflection
sensitivities for both tubes the same ?

Good luck with it - I think you'ree going to need it, but it's nice to see
that a sense of experimentation still exists out there - it's the sort of
thing that I would have been playing with 30 years ago ...


Arfa


  #14   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 225
Default [Update - Done] what or how to check CRT HV anode wire repair ?


"Arfa Daily" wrote in message
...

"robb" wrote in message
...
Silicon cured, CRT installed and tested.
Sorry no fireworks or shooting flames

Problems:
==========
The display is skewed and the intensity and focus are off.
I was not expecting te new CRT to have hyper-intensity

troubles.
That is... from no visible trace to oversaturated CRT

brightness
is a very small range of knob motion maybe a 1/4-1/3 of he

full
turn .
And the focus is very sensitive, touch sensitive ? was not
before.


It sounds to me like this replacement CRT might not be quite as

'compatible'
as you had hoped ... :-( Maybe that's part of the reason that

the PDA lead
was not long enough to fit in your chassis i.e. to stop such a

substitution
taking place. As far as the trace being 'skewed' do you mean

that it is not
perfectly horizontal, or that it is trapezoidally distorted ?

If the former,
then most decent 'scopes have a trace rotation control

somewhere. As far as
the brightness / focus issues go, that is likely to be quite

difficult to
resolve, and will probably require changes to be made to the

component
values in the resistor chains providing the biasing voltages to

the various
electrodes. I would suggest that you will not get too far with

that, without
having schematics for both the 'scope that you've put the tube

in, and the
one that it came out of, so that you can make comparisons of

values and
expected voltages. Just as a matter of interest, are the quoted

deflection
sensitivities for both tubes the same ?

Good luck with it - I think you'ree going to need it, but it's

nice to see
that a sense of experimentation still exists out there - it's

the sort of
thing that I would have been playing with 30 years ago ...


Hello Arfa,
It is a Tek scope.
There are lots of pots for adjusting the CRT params.

The CRT was replaced with its **reverse** compatible replacement
P/N.

That is, typically one replaces the earlier model CRT with the
newer model and i have done the reverse. I replaced the newer
model with the earlier model. Unless it was a "one way
compatibility" then technically it should work.

The HV lead was longer in newer models because of physical change
to the Flyback/HV multiplier transformer and orientation. The
earlier model machines had an HV Jack on an 3" HV lead coming off
the Flyback the newer models have te HV Jack on the Flyback
directly.

So you need just 1" (2.5 cm) more HV lead to make it there.

Hopefully i can cure problems with the adjustments, as I do not
really want to modify the original PCB /schematic values.

Thanks for help and ideas Arfa,
robb

  #15   Report Post  
Posted to sci.electronics.basics,sci.electronics.equipment,sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default [Update - Done] what or how to check CRT HV anode wire repair ?


"robb" wrote in message
...

"Arfa Daily" wrote in message
...

"robb" wrote in message
...
Silicon cured, CRT installed and tested.
Sorry no fireworks or shooting flames

Problems:
==========
The display is skewed and the intensity and focus are off.
I was not expecting te new CRT to have hyper-intensity

troubles.
That is... from no visible trace to oversaturated CRT

brightness
is a very small range of knob motion maybe a 1/4-1/3 of he

full
turn .
And the focus is very sensitive, touch sensitive ? was not
before.


It sounds to me like this replacement CRT might not be quite as

'compatible'
as you had hoped ... :-( Maybe that's part of the reason that

the PDA lead
was not long enough to fit in your chassis i.e. to stop such a

substitution
taking place. As far as the trace being 'skewed' do you mean

that it is not
perfectly horizontal, or that it is trapezoidally distorted ?

If the former,
then most decent 'scopes have a trace rotation control

somewhere. As far as
the brightness / focus issues go, that is likely to be quite

difficult to
resolve, and will probably require changes to be made to the

component
values in the resistor chains providing the biasing voltages to

the various
electrodes. I would suggest that you will not get too far with

that, without
having schematics for both the 'scope that you've put the tube

in, and the
one that it came out of, so that you can make comparisons of

values and
expected voltages. Just as a matter of interest, are the quoted

deflection
sensitivities for both tubes the same ?

Good luck with it - I think you'ree going to need it, but it's

nice to see
that a sense of experimentation still exists out there - it's

the sort of
thing that I would have been playing with 30 years ago ...


Hello Arfa,
It is a Tek scope.
There are lots of pots for adjusting the CRT params.

The CRT was replaced with its **reverse** compatible replacement
P/N.

That is, typically one replaces the earlier model CRT with the
newer model and i have done the reverse. I replaced the newer
model with the earlier model. Unless it was a "one way
compatibility" then technically it should work.

The HV lead was longer in newer models because of physical change
to the Flyback/HV multiplier transformer and orientation. The
earlier model machines had an HV Jack on an 3" HV lead coming off
the Flyback the newer models have te HV Jack on the Flyback
directly.

So you need just 1" (2.5 cm) more HV lead to make it there.

Hopefully i can cure problems with the adjustments, as I do not
really want to modify the original PCB /schematic values.

Thanks for help and ideas Arfa,
robb

Hmmmm. Sometimes, compatible substitution *is* a one-way street. If the
parameters of the two tubes were sufficiently similar, I would not have
expected there to be a huge difference in the external setups, or for the
operation of the user controls to become 'bunched' as you described. There
are a couple of Tek 'scope experts who pop up on here from time to time who
would be much better qualified to advise you on the specifics of your
problems than I, so hopefully one of them will dive in to help you shortly !

Arfa


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CRT HV wire repair ? robb Electronics Repair 11 January 21st 08 06:34 AM
About TV Repair: How do I disconnect Anode connection from Circuit board? Red Cloud Electronics Repair 4 June 10th 07 05:36 PM
Mits Wire EDM Program Check Error SoCalMike Metalworking 2 April 4th 05 07:39 PM
Wire for range repair... zyx321 Home Repair 11 November 26th 04 03:41 PM
Freezer - what to check before resorting to repair man - advice needed Nigel UK diy 1 September 10th 03 11:48 PM


All times are GMT +1. The time now is 12:24 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"