tektronix 465 repair

L

Lee Gleason

Guest
I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's going
on with it.

I was told it was completely dead and not repairable when I salvaged it -
I thought, I'll be the judge of that. Initially it was stone dead - no
trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown, and
when replaced, it would blow again immediately. None of the panel lights or
the fan would come on, and all the power supply voltages were low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and then
found another cap, C1419, that was shorted that was blowing F1419. Replaced
it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then nothing.
Letting off the beam finder and adjusting the controls for a normal trace,
I noticed that the whole screen is sort of illuminated. If I slow the sweep
way down, I see that a dim 3/4 inch wide by whole screen tall bar goes
across the screen, at about the rate you'd expect on the slow sweep
settings - so that looks like the HV and the time base stuff is more or less
working.

I'm guessing I have some sort of vertical amplifier problem. Before diving
back into the schematics, I thought I'd ask, anyone ever seen this symptom
before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
 
On 12/20/2014 5:03 PM, Lee Gleason wrote:
I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead -
no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown,
and when replaced, it would blow again immediately. None of the panel
lights or the fan would come on, and all the power supply voltages were
low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and
then found another cap, C1419, that was shorted that was blowing F1419.
Replaced it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated. If
I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time base
stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?
Click to expand...

Re-capping the whole thing would be a good start, I expect. I have a
475 that I'll have to do that to one of these days.


Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
On 12/20/2014 2:03 PM, Lee Gleason wrote:
I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead -
no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown,
and when replaced, it would blow again immediately. None of the panel
lights or the fan would come on, and all the power supply voltages were
low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and
then found another cap, C1419, that was shorted that was blowing F1419.
Replaced it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated. If
I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time base
stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
Click to expand...

I'd go check all the caps. Over the last few years, I've had more and more
caps fail in tek stuff. Originally was the teardrop tantalums, but more
recently, all types.
I don't have a schematic handy, but if you can check the bleeder
resistors in the HV supply, I'd do that. There should be HV test
point that you can check with a normal multimeter.
 
On 12/20/2014 4:03 PM, Lee Gleason wrote:
I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead -
no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown,
and when replaced, it would blow again immediately. None of the panel
lights or the fan would come on, and all the power supply voltages were
low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and
then found another cap, C1419, that was shorted that was blowing F1419.
Replaced it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated. If
I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time base
stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
Click to expand...

There's a good TEK yahoo group that might be helpful.

Mikek
 
"Lee Gleason" <lee.gleason@comcast.net> wrote in message
news:5495f247$0$13196$882e7ee2@usenet-news.net...
I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's going
on with it.

I was told it was completely dead and not repairable when I salvaged it -
I thought, I'll be the judge of that. Initially it was stone dead - no
trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown, and
when replaced, it would blow again immediately. None of the panel lights
or the fan would come on, and all the power supply voltages were low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and
then found another cap, C1419, that was shorted that was blowing F1419.
Replaced it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then nothing.
Letting off the beam finder and adjusting the controls for a normal trace,
I noticed that the whole screen is sort of illuminated. If I slow the
sweep way down, I see that a dim 3/4 inch wide by whole screen tall bar
goes across the screen, at about the rate you'd expect on the slow sweep
settings - so that looks like the HV and the time base stuff is more or
less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen this
symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
Click to expand...
I would recommend going through the adjustments section of the service
manual. That will offer you a chance to find any out-of-spec parts. The Tek
manuals are very complete and include a theory of operation section that
will answer most questions.
Pay attention to the ripple/noise specs on the power supply test points. The
+55 volt rail serves as the main reference for the rest of the supplies.

Regards
 
On 12/20/2014 3:43 PM, Tom Miller wrote:
"Lee Gleason" <lee.gleason@comcast.net> wrote in message
news:5495f247$0$13196$882e7ee2@usenet-news.net...

I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead
- no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419)
blown, and when replaced, it would blow again immediately. None of
the panel lights or the fan would come on, and all the power supply
voltages were low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it
and then found another cap, C1419, that was shorted that was blowing
F1419. Replaced it and now the lights and scale illumination and fan
come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated.
If I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time
base stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
I would recommend going through the adjustments section of the service
manual. That will offer you a chance to find any out-of-spec parts. The
Tek manuals are very complete and include a theory of operation section
that will answer most questions.
Pay attention to the ripple/noise specs on the power supply test points.
The +55 volt rail serves as the main reference for the rest of the
supplies.

Regards
Click to expand...
That's a good idea, but concentrate on getting the numbers close by
fixing busted stuff. I'd recommend against randomly tweaking stuff
in an attempt to fix hardware problems.
That assumes that the previous owner exercised similar restraint
when he tried to fix it.
 
On Sat, 20 Dec 2014 15:03:27 -0700, Lee Gleason <lee.gleason@comcast.net>
wrote:

I have a crusty old TEK 465 I saved from going into the garbage a few
years back. Finally got time to pull it off the shelf and see what's
going on with it.

I was told it was completely dead and not repairable when I salvaged
it - I thought, I'll be the judge of that. Initially it was stone dead -
no trace, no lights, no fan nothing. I found a 1.5 A fuse (F1419) blown,
and when replaced, it would blow again immediately. None of the panel
lights or the fan would come on, and all the power supply voltages were
low.

I found one bad capacitor that was grounding the +15, when it started
smoking (some faults are easier to locate than others). Replaced it and
then found another cap, C1419, that was shorted that was blowing F1419.
Replaced it and now the lights and scale illumination and fan come on.

When I press the beam finder, I get a large dot flash and then
nothing. Letting off the beam finder and adjusting the controls for a
normal trace, I noticed that the whole screen is sort of illuminated. If
I slow the sweep way down, I see that a dim 3/4 inch wide by whole
screen tall bar goes across the screen, at about the rate you'd expect
on the slow sweep settings - so that looks like the HV and the time base
stuff is more or less working.

I'm guessing I have some sort of vertical amplifier problem. Before
diving back into the schematics, I thought I'd ask, anyone ever seen
this symptom before?

--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason@comcast.net
Click to expand...

Did you ask the TEK group?

<TekScopes@yahoogroups.com>

I saw some detailed info go by there, often.
 
On Sat, 20 Dec 2014 16:03:27 -0600, "Lee Gleason"
<lee.gleason@comcast.net> wrote:

I'm guessing I have some sort of vertical amplifier problem. Before diving
back into the schematics, I thought I'd ask, anyone ever seen this symptom
before?
Click to expand...

These may help:
<http://www.eevblog.com/forum/projects/tektronix-465-repair-and-restoration/>
<http://www.spurtikus.de/basteln/repair/tek465/index.html>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
On 12/21/2014 10:59 AM, Jeff Liebermann wrote:
On Sat, 20 Dec 2014 16:03:27 -0600, "Lee Gleason"
wrote:

I'm guessing I have some sort of vertical amplifier problem. Before diving
back into the schematics, I thought I'd ask, anyone ever seen this symptom
before?

These may help:
http://www.eevblog.com/forum/projects/tektronix-465-repair-and-restoration/
http://www.spurtikus.de/basteln/repair/tek465/index.html
Click to expand...


Great Links!

Here's another that may be useful (see the first two items listed under
"Documents"): <http://www.hakanh.com/dl/>

Happy Holidays, everyone :)
 
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