577 D2 question(s)


Andy Warner
 

I bought a mostly working 577/D2 recently.
What I regard as the most serious problem with it is the trace intensity.

What I see is that the maximum intensity occurs at approx 60% of the front
panel adjustment (R1200) - moving it either direction from the peak results
in a dimmer trace.
The bulk of the trace (when the beam is moving fast) is not particularly
bright, but the start and end of the traces is good.

I have cleaned and checked R1200 operation, and I believe the pot is good.

Also, the dimming signal from the collector supply board (R592) seems to be
correct (e.g. near zero V when the collector voltage is non-zero.) However,
I don't really see an obvious dimming effect on the trace when I turn the
collector supply down to zero.

I have not yet been able to measure the HT voltage (looking for a probe to
help me do that - advice welcome.)

In the interim, I wanted to trace the operation of the Z amplifier circuit
(Q1222,1226,1234), but the service manual I have (thank you Artek) is
silent on removing the deflection amp/high voltage board.
It honestly looks like a royal pain to remove for service - does anyone
here have any hints and tips ?
The schematic has a couple of helpful waveforms shown, but I have zero idea
how you are expected to probe up the board, given the location of the
side-rail that obscures the lower half of the board.

Any 577 owners out there got advice to share ?
--
Andy


ChuckA
 

Andy

Removing the HV board is a PIA as you have to unsolder 11 or so connections on the top of the board and a screw holding the heat sink for the oscillator transistor before you can work it out. Gets easier the second or third time. I wish TEK had used push on connectors like on the 576 boards.

Be careful bending the plastic clip in supports that hold the board, very easy to snap off.

Definitely was a bad design for working on the board in the cabinet, should have had the side rail removable.

Chuck

On 5/3/2021 3:02 PM, Andy Warner wrote:
I bought a mostly working 577/D2 recently.
What I regard as the most serious problem with it is the trace intensity.

What I see is that the maximum intensity occurs at approx 60% of the front
panel adjustment (R1200) - moving it either direction from the peak results
in a dimmer trace.
The bulk of the trace (when the beam is moving fast) is not particularly
bright, but the start and end of the traces is good.

I have cleaned and checked R1200 operation, and I believe the pot is good.

Also, the dimming signal from the collector supply board (R592) seems to be
correct (e.g. near zero V when the collector voltage is non-zero.) However,
I don't really see an obvious dimming effect on the trace when I turn the
collector supply down to zero.

I have not yet been able to measure the HT voltage (looking for a probe to
help me do that - advice welcome.)

In the interim, I wanted to trace the operation of the Z amplifier circuit
(Q1222,1226,1234), but the service manual I have (thank you Artek) is
silent on removing the deflection amp/high voltage board.
It honestly looks like a royal pain to remove for service - does anyone
here have any hints and tips ?
The schematic has a couple of helpful waveforms shown, but I have zero idea
how you are expected to probe up the board, given the location of the
side-rail that obscures the lower half of the board.

Any 577 owners out there got advice to share ?
--
See Early TV at:

www.myvintagetv.com


Dave Voorhis
 

On 3 May 2021, at 20:02, Andy Warner <andyw@pobox.com> wrote:

I bought a mostly working 577/D2 recently.
What I regard as the most serious problem with it is the trace intensity.

What I see is that the maximum intensity occurs at approx 60% of the front
panel adjustment (R1200) - moving it either direction from the peak results
in a dimmer trace.
The bulk of the trace (when the beam is moving fast) is not particularly
bright, but the start and end of the traces is good.

I have cleaned and checked R1200 operation, and I believe the pot is good.

Also, the dimming signal from the collector supply board (R592) seems to be
correct (e.g. near zero V when the collector voltage is non-zero.) However,
I don't really see an obvious dimming effect on the trace when I turn the
collector supply down to zero.

I have not yet been able to measure the HT voltage (looking for a probe to
help me do that - advice welcome.)

In the interim, I wanted to trace the operation of the Z amplifier circuit
(Q1222,1226,1234), but the service manual I have (thank you Artek) is
silent on removing the deflection amp/high voltage board.
It honestly looks like a royal pain to remove for service - does anyone
here have any hints and tips ?
The schematic has a couple of helpful waveforms shown, but I have zero idea
how you are expected to probe up the board, given the location of the
side-rail that obscures the lower half of the board.

Any 577 owners out there got advice to share ?
My first 577 (a D1) was very dim — and it came with a spare CRT — but essentially worked for a while after I got it home. Then it suddenly went completely dark. Rapid onset blackness seemed unlikely to be CRT wear so I checked the Z-axis and sure enough, two transistors (I don’t recall which) in that circuit had failed.

But afterward it was as dim as before, and with similar behaviour to what you describe — brightest in roughly centre travel, dimmer either higher or lower.

I replaced the CRT with the spare it came with and that fixed it. Hopefully not the case with yours.

My second 577 (another D1) was also a tad dim — but not as bad as my first — and also reaching a peak somewhat past centre brightness. Notably, it has improved with use and whilst not the brightest CRT I’ve ever seen, more than usable.

With both units I went through the calibration procedure, including checking/setting HT voltage. I checked it with an older VOM that goes to 5000 volts, taking all reasonable precautions to hook it up carefully with good well-insulated leads and clips and make sure I’m not anywhere near, let alone touching, any possible conduction path whilst it’s powered.

The dimming effect of turning down the collector voltage should happen only in the last degree or so of rotation, essentially when it hits the zero position.


Dave Voorhis
 

On 3 May 2021, at 22:04, Dave Voorhis via groups.io <voorhis=gmail.com@groups.io> wrote:

On 3 May 2021, at 20:02, Andy Warner <andyw@pobox.com> wrote:

...
Any 577 owners out there got advice to share ?
My first 577 (a D1) was very dim — and it came with a spare CRT — but essentially worked for a while after I got it home. Then it suddenly went completely dark. Rapid onset blackness seemed unlikely to be CRT wear so I checked the Z-axis and sure enough, two transistors (I don’t recall which) in that circuit had failed.
I thought there was a chance I might have made notes of the repair, and sure enough I did:

Q1234 151-0406-00 Transistor:PNP:TO-39 04713 ST1264 2N5401
Q1226 151-0347-00 Transistor:NPN:TO-92 04713 SPS7951 2N5551


 

The symptom is known as "double peaking" and indicates the CRT has cathode interface, AKA cathode poisoning. The CRT is near the end of its life. Applying 12 volts for 10 or 15 minutes to the filament (with the instrument power off, since, in operation, the filament is at -3400 volts), may effect a temporary repair. Access to the filament is easy via a two-pin connector on the HV/deflection board.

--
Bob Haas


Andy Warner
 

Thanks all,
I was hoping it would not be the tube, I have been lucky enough to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has cathode
interface, AKA cathode poisoning. The CRT is near the end of its life.
Applying 12 volts for 10 or 15 minutes to the filament (with the instrument
power off, since, in operation, the filament is at -3400 volts), may effect
a temporary repair. Access to the filament is easy via a two-pin connector
on the HV/deflection board.

--
Bob Haas





--
Andy


Eric
 

Andy tubes are really available for the 577 d2 they can be salvaged from
one of the 5000 series scopes. If I remember correctly the 5220 is the one
you want to find. It is a direct drop in replacement I can confirm the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky enough to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts), may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy






Paul Amaranth
 

Early on, Tek listed the 5000 mainfame and display unit seperately, so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of replacing
the CRT unit if it goes bad. You should be able to find a donor 5000 scope
around $50. Despite the huge screens nobody wants them because of the low
bandwidth. Heck, you can probably find one free if you want to look hard
enough.

I have an old 5000 scope with a D11 storage display that I want to put into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you might get
a couple hundred hours out of it. That will give you time while you look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged from
one of the 5000 series scopes. If I remember correctly the 5220 is the one
you want to find. It is a direct drop in replacement I can confirm the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky enough to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts), may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy










!DSPAM:6092b6ab251027023613042!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


ChuckA
 

I've had good luck using a Sencore CR-70 restoring  a TDS-648A and a HP3562A CRT, both were so dim as not usable.

Running the filament about 40%-50% higher for a time was a old method to sometimes make a dim picture tube in early TV's come back to life for a short time. TV brighteners were common in late 40's and early 50's to extend the life of a TV, they had a small autotransformer and ran the filament at around 8V.

Chuck

On 5/5/2021 11:05 AM, Andy Warner wrote:
Thanks all,
I was hoping it would not be the tube, I have been lucky enough to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has cathode
interface, AKA cathode poisoning. The CRT is near the end of its life.
Applying 12 volts for 10 or 15 minutes to the filament (with the instrument
power off, since, in operation, the filament is at -3400 volts), may effect
a temporary repair. Access to the filament is easy via a two-pin connector
on the HV/deflection board.

--
Bob Haas





--
See Early TV at:

www.myvintagetv.com


Eric
 

The 5220 is an old 10Mhz or 20Mhz 5000 frame. I would much rather have a
functional curve tracer then at 20Mhz scope but that is just me.

Eric

On Wed, May 5, 2021, 11:38 AM Paul Amaranth <paul@auroragrp.com> wrote:

Early on, Tek listed the 5000 mainfame and display unit seperately, so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of replacing
the CRT unit if it goes bad. You should be able to find a donor 5000 scope
around $50. Despite the huge screens nobody wants them because of the low
bandwidth. Heck, you can probably find one free if you want to look hard
enough.

I have an old 5000 scope with a D11 storage display that I want to put into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you might get
a couple hundred hours out of it. That will give you time while you look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged from
one of the 5000 series scopes. If I remember correctly the 5220 is the
one
you want to find. It is a direct drop in replacement I can confirm the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky enough
to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely
have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying
some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to
be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its
life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts), may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy










!DSPAM:6092b6ab251027023613042!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows






Andy Warner
 

Thanks for the mapping to the 5000 series, did not realize that.

My father-in-law was the TV repair man for a small town in the midwest for
40 years, I am sure we threw out a couple of rejuvenators when we cleared
out his workshop after he died, but that was well before I got into owning
Tek gear - little did I know.

On Wed, May 5, 2021 at 11:16 AM Eric <ericsp@gmail.com> wrote:

The 5220 is an old 10Mhz or 20Mhz 5000 frame. I would much rather have a
functional curve tracer then at 20Mhz scope but that is just me.

Eric

On Wed, May 5, 2021, 11:38 AM Paul Amaranth <paul@auroragrp.com> wrote:

Early on, Tek listed the 5000 mainfame and display unit seperately, so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of
replacing
the CRT unit if it goes bad. You should be able to find a donor 5000
scope
around $50. Despite the huge screens nobody wants them because of the
low
bandwidth. Heck, you can probably find one free if you want to look hard
enough.

I have an old 5000 scope with a D11 storage display that I want to put
into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you might
get
a couple hundred hours out of it. That will give you time while you look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged
from
one of the 5000 series scopes. If I remember correctly the 5220 is the
one
you want to find. It is a direct drop in replacement I can confirm the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky
enough
to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely
have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying
some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to
be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its
life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts),
may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy










!DSPAM:6092b6ab251027023613042!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows









--
Andy


Andy Warner
 

From a brief scan of tekwiki - it looks like if I need a 154-0633-10, I am
specifically on the hunt for a 5110 with serial # >= B103611, and a known
bright trace.

Given that info, it looks like I have a couple of options on ebay,
including a bare tube - but of course no real info on trace brightness...

On Wed, May 5, 2021 at 11:46 AM Andy Warner <andyw@pobox.com> wrote:

Thanks for the mapping to the 5000 series, did not realize that.

My father-in-law was the TV repair man for a small town in the midwest for
40 years, I am sure we threw out a couple of rejuvenators when we cleared
out his workshop after he died, but that was well before I got into owning
Tek gear - little did I know.

On Wed, May 5, 2021 at 11:16 AM Eric <ericsp@gmail.com> wrote:

The 5220 is an old 10Mhz or 20Mhz 5000 frame. I would much rather have a
functional curve tracer then at 20Mhz scope but that is just me.

Eric

On Wed, May 5, 2021, 11:38 AM Paul Amaranth <paul@auroragrp.com> wrote:

Early on, Tek listed the 5000 mainfame and display unit seperately, so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of
replacing
the CRT unit if it goes bad. You should be able to find a donor 5000
scope
around $50. Despite the huge screens nobody wants them because of the
low
bandwidth. Heck, you can probably find one free if you want to look
hard
enough.

I have an old 5000 scope with a D11 storage display that I want to put
into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you might
get
a couple hundred hours out of it. That will give you time while you
look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged
from
one of the 5000 series scopes. If I remember correctly the 5220 is
the
one
you want to find. It is a direct drop in replacement I can confirm
the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky
enough
to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely
have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including
applying
some
current limited HT between cathode and grid, or is there a reason
you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears
to
be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT
has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its
life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts),
may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy










!DSPAM:6092b6ab251027023613042!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows









--
Andy





--
Andy


Paul Amaranth
 

Well there's a 5103N on ebay right now for $13.99. Power's up but only
shows a dot (duh, for a bare mainframe). Kicker is the $50 in shipping.
Have any swaps going on near you? Also check Craigslist.

You don't have to move the tube, you can swap the entire display unit.

Paul

On Wed, May 05, 2021 at 12:37:43PM -0500, Andy Warner wrote:
From a brief scan of tekwiki - it looks like if I need a 154-0633-10, I am
specifically on the hunt for a 5110 with serial # >= B103611, and a known
bright trace.

Given that info, it looks like I have a couple of options on ebay,
including a bare tube - but of course no real info on trace brightness...

On Wed, May 5, 2021 at 11:46 AM Andy Warner <andyw@pobox.com> wrote:

Thanks for the mapping to the 5000 series, did not realize that.

My father-in-law was the TV repair man for a small town in the midwest for
40 years, I am sure we threw out a couple of rejuvenators when we cleared
out his workshop after he died, but that was well before I got into owning
Tek gear - little did I know.

On Wed, May 5, 2021 at 11:16 AM Eric <ericsp@gmail.com> wrote:

The 5220 is an old 10Mhz or 20Mhz 5000 frame. I would much rather have a
functional curve tracer then at 20Mhz scope but that is just me.

Eric

On Wed, May 5, 2021, 11:38 AM Paul Amaranth <paul@auroragrp.com> wrote:

Early on, Tek listed the 5000 mainfame and display unit seperately, so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of
replacing
the CRT unit if it goes bad. You should be able to find a donor 5000
scope
around $50. Despite the huge screens nobody wants them because of the
low
bandwidth. Heck, you can probably find one free if you want to look
hard
enough.

I have an old 5000 scope with a D11 storage display that I want to put
into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you might
get
a couple hundred hours out of it. That will give you time while you
look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged
from
one of the 5000 series scopes. If I remember correctly the 5220 is
the
one
you want to find. It is a direct drop in replacement I can confirm
the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky
enough
to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely
have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including
applying
some
current limited HT between cathode and grid, or is there a reason
you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears
to
be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT
has
cathode
interface, AKA cathode poisoning. The CRT is near the end of its
life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
instrument
power off, since, in operation, the filament is at -3400 volts),
may
effect
a temporary repair. Access to the filament is easy via a two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy











--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows









--
Andy





--
Andy






!DSPAM:6092d803256101157150146!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Eric
 

If you are shopping the tube is easly identifiable by the unique marks in
the lower left corner. 5110 is the right number now that I remember which
also means don't feel bad about scrapping the frame it is only 10 Mhz so
the tube is in a better place in my opinion

Eric

On Wed, May 5, 2021, 1:38 PM Andy Warner <andyw@pobox.com> wrote:

From a brief scan of tekwiki - it looks like if I need a 154-0633-10, I am
specifically on the hunt for a 5110 with serial # >= B103611, and a known
bright trace.

Given that info, it looks like I have a couple of options on ebay,
including a bare tube - but of course no real info on trace brightness...

On Wed, May 5, 2021 at 11:46 AM Andy Warner <andyw@pobox.com> wrote:

Thanks for the mapping to the 5000 series, did not realize that.

My father-in-law was the TV repair man for a small town in the midwest
for
40 years, I am sure we threw out a couple of rejuvenators when we cleared
out his workshop after he died, but that was well before I got into
owning
Tek gear - little did I know.

On Wed, May 5, 2021 at 11:16 AM Eric <ericsp@gmail.com> wrote:

The 5220 is an old 10Mhz or 20Mhz 5000 frame. I would much rather have
a
functional curve tracer then at 20Mhz scope but that is just me.

Eric

On Wed, May 5, 2021, 11:38 AM Paul Amaranth <paul@auroragrp.com>
wrote:

Early on, Tek listed the 5000 mainfame and display unit seperately,
so
you could get a 5103 frame and a D11 storage display. That doesn't
seem to have lasted very long so it gets very confusing, but the only
difference between a D10 or D11 and the 577 display is the probe
callibration terminal on the front.

One of the big advantages of the 577 over the 576 is the ease of
replacing
the CRT unit if it goes bad. You should be able to find a donor 5000
scope
around $50. Despite the huge screens nobody wants them because of
the
low
bandwidth. Heck, you can probably find one free if you want to look
hard
enough.

I have an old 5000 scope with a D11 storage display that I want to
put
into
my non-storage 577 one of these days.

Go ahead with the full rejuvination, you can't lose much and you
might
get
a couple hundred hours out of it. That will give you time while you
look
for a 5000 donor.

What's a 5220? I can't find a reference to that.

Paul

On Wed, May 05, 2021 at 11:15:27AM -0400, Eric wrote:
Andy tubes are really available for the 577 d2 they can be salvaged
from
one of the 5000 series scopes. If I remember correctly the 5220 is
the
one
you want to find. It is a direct drop in replacement I can confirm
the
scope later today of need be.

Eric

On Wed, May 5, 2021, 11:05 AM Andy Warner <andyw@pobox.com> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky
enough
to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I
likely
have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including
applying
some
current limited HT between cathode and grid, or is there a reason
you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which
appears
to
be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <robeughaas@gmail.com> wrote:

The symptom is known as "double peaking" and indicates the CRT
has
cathode
interface, AKA cathode poisoning. The CRT is near the end of
its
life.
Applying 12 volts for 10 or 15 minutes to the filament (with
the
instrument
power off, since, in operation, the filament is at -3400
volts),
may
effect
a temporary repair. Access to the filament is easy via a
two-pin
connector
on the HV/deflection board.

--
Bob Haas





--
Andy










!DSPAM:6092b6ab251027023613042!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows









--
Andy





--
Andy






 

On Wed, May 5, 2021 at 05:44 PM, ChuckA wrote:
I've had good luck using a Sencore CR-70 restoring  a TDS-648A and a HP3562A CRT....
Hi Chuck,

do you, or anyone else, have an idea what the Sencore and other rejuvenators are actually doing?

cheers
Martin


greenboxmaven
 

Rejuvenators send a blast of current through the cathode to the grid and often other elements. This explodes/erodes the top layer of the cathode coating to (Hopefully!) expose an active and uncontaminated layer beneath. The nature of the pulse, it's method of current limiting, and it's waveform are all the "trade secrets" of each manufacturer. Different rejuvinators tended to work better for some manufacturers of CRTs than others.

   Bruce Gentry, KA2IVY

On 5/6/21 2:54, Martin wrote:
On Wed, May 5, 2021 at 05:44 PM, ChuckA wrote:
I've had good luck using a Sencore CR-70 restoring  a TDS-648A and a HP3562A CRT....
Hi Chuck,

do you, or anyone else, have an idea what the Sencore and other rejuvenators are actually doing?

cheers
Martin




ChuckA
 

The CR70 has 2 functions REJUVENATE and RESTORE.

From the manual:

In REJUV function, cathode and G2 are tied together. Normal filament voltage is applied and a 1K ohm resistor is in series with discharging capacitor to limit surge current. Pressing REJUV, G1 is positively biased, allowing a sudden surge current to flow from cathode to G1. This current quickly drops to zero, removing the bias on G1. This current surge cracks any coating or removes any contamination on the cathode, allowing cathode to supply proper emission current.

There are 3 levels of restoration. Restoration brings new emitting material to the surface of the cathode by removing old material. In AUTO RESTORE the CR70 cycles the beam current 3 times, in MANUAL RESTORE the tube will draw current as long as the button is pressed. In AUTO and MANUAL 1 current is limited to 100ma, MANUAL 2 current is limited to 150ma.
The filament is increased 50% to superheat the cathode and soften the old material. Cathode and G2 are tied together, places zero bias on the tube and allows maximum current to flow. No current flows until 230 volts is applied to G1. This large current "boils off" the poisoning material, allowing new emitting material to come to the surface. Maximum restoration is reached when all new emitting material is exposed and is indicated as a peak current reading on the CR70 meter.

I've only had to use the RESTORE function on the weak tubes I had to get a usable display.
The REJUVENATE function can be brutal, I have completely killed a couple of picture tubes using this function more than once on a really weak tube.

Chuck

On 5/6/2021 2:54 AM, Martin wrote:
Hi Chuck,
do you, or anyone else, have an idea what the Sencore and other rejuvenators are actually doing?

cheers
Martin

--
See Early TV at:

www.myvintagetv.com


-
 

The TV CRT rejuvenators simply place an excessive voltage on the filament
in the hope it will burn some of the "glaze?" that have built up on the
cathode and that that will increase the electron emissions from the
cathode. IIRC they would apply about 16 volts to a 12 volt filament. IIRC
you were only supposed to use the "boost" for about 5 seconds at a time and
no longer. And no more than three such boosts. Usually by the time that
people brought in their TVs for repair the picture was so bad, and the CRT
was so worn out, that there wasn't anything left to lose by attempting to
boost the CRT. The rejuvenators usually did help but only to a limited
degree and I think that the improvement was very temporary.

On Thu, May 6, 2021 at 2:55 AM Martin <musaeum@arcor.de> wrote:

On Wed, May 5, 2021 at 05:44 PM, ChuckA wrote:
I've had good luck using a Sencore CR-70 restoring a TDS-648A and a
HP3562A CRT....

Hi Chuck,

do you, or anyone else, have an idea what the Sencore and other
rejuvenators are actually doing?

cheers
Martin






Andy Warner
 

Thanks for the pointers to 5110 scopes having the same tube. I was lucky
enough to have a friend of a friend who had a late model unit gathering
dust.

I swapped the tube, and now have beautiful, crisp, bright traces.

I agree with Eric that this is a far nobler use for the tube than in a
low-spec 'scope.

Greatly appreciate the advice and suggestions.

On Thu, May 6, 2021, 18:45 - <rrrr6789@gmail.com> wrote:

The TV CRT rejuvenators simply place an excessive voltage on the filament
in the hope it will burn some of the "glaze?" that have built up on the
cathode and that that will increase the electron emissions from the
cathode. IIRC they would apply about 16 volts to a 12 volt filament. IIRC
you were only supposed to use the "boost" for about 5 seconds at a time and
no longer. And no more than three such boosts. Usually by the time that
people brought in their TVs for repair the picture was so bad, and the CRT
was so worn out, that there wasn't anything left to lose by attempting to
boost the CRT. The rejuvenators usually did help but only to a limited
degree and I think that the improvement was very temporary.

On Thu, May 6, 2021 at 2:55 AM Martin <musaeum@arcor.de> wrote:

On Wed, May 5, 2021 at 05:44 PM, ChuckA wrote:
I've had good luck using a Sencore CR-70 restoring a TDS-648A and a
HP3562A CRT....

Hi Chuck,

do you, or anyone else, have an idea what the Sencore and other
rejuvenators are actually doing?

cheers
Martin










Jim Ford
 

Hey, don't discount the 5110's low bandwidth; it's great for audio.  While I appreciate a GHz scope and have several S-4 sampling heads, a 7S12, a 7S11, and a couple of 7000 series mainframes, for low frequency signals, the 5103N D10 with its low-noise, razor-sharp traces is the winner.  Dead simple to work on, too.  I call mine Low and Slow for Audio!        Jim FordSent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Andy Warner <andyw@pobox.com> Date: 5/7/21 7:29 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] 577 D2 question(s) Thanks for the pointers to 5110 scopes having the same tube. I was luckyenough to have a friend of a friend who had a late model unit gatheringdust.I swapped the tube, and now have beautiful, crisp, bright traces.I agree with Eric that this is a far nobler use for the tube than in alow-spec 'scope.Greatly appreciate the advice and suggestions.On Thu, May 6, 2021, 18:45 - <rrrr6789@gmail.com> wrote:>   The TV CRT rejuvenators simply place an excessive voltage on the filament> in the hope it will burn some of the "glaze?" that have built up on the> cathode and that that will increase the electron emissions from the> cathode. IIRC they would apply about 16 volts to a 12 volt filament. IIRC> you were only supposed to use the "boost" for about 5 seconds at a time and> no longer. And no more than three such boosts. Usually by the time that> people brought in their TVs for repair the picture was so bad, and the CRT> was so worn out, that there wasn't anything left to lose by attempting to> boost the CRT. The rejuvenators usually did help but only to a limited> degree and I think that the improvement was very temporary.>> On Thu, May 6, 2021 at 2:55 AM Martin <musaeum@arcor.de> wrote:>> > On Wed, May  5, 2021 at 05:44 PM, ChuckA wrote:> > > I've had good luck using a Sencore CR-70 restoring  a TDS-648A and a> > HP3562A CRT....> >> > Hi Chuck,> >> > do you, or anyone else, have an idea what the Sencore and other> > rejuvenators are actually doing?> >> > cheers> > Martin> >> >> >> >> >> >>>> >>>