Toshiba TV29C90 problem; Image fades to black...

[Richard Henry]

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:v4edneO2SYsvtCDenZ2dnUVZ_tqdnZ2d@rcn.net...

Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones,
but HP-1741A storage scope.

Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut two
(or was it 3?) slots that each cover 175 (115?) degrees through the body
of the knob.
They did that so that you could see the light mounted on the panel through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is already
at least 18 years old), you will snap those thin little bits of plastic,
and your knob will be gone, and your scope will be unusable. Forget about
gluing it, as there was barely enough strength with the virgin plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.

Tektronix did the same thing with their horizontal knobs, but they
knew enough about materials engineering to make the body of the knob
out of aluminum, and make the grip surface of the knob out of plastic.

I never had a HP scope that I liked, or would use unless there was no Tek
scope available.

 

[peter.visser@12move.nl]

I "repaired" the knobs of my HP1707B (same problem) with success by
using Epoxy Patch Bond
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[Dave Edwards]

Still using the 275Mhz hp1726A that was given to me when I started working
for HP in '83.
I keep it covered when not being used, so it still looks like new. Perhaps
some day it will crap out, and I'll try a Tek!!


"Richard Henry" <rphenry@home.com> wrote in message
news:424tgaF1h9oseU1@individual.net...

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:v4edneO2SYsvtCDenZ2dnUVZ_tqdnZ2d@rcn.net...
Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones,
but HP-1741A storage scope.

Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut two
(or was it 3?) slots that each cover 175 (115?) degrees through the body
of the knob.
They did that so that you could see the light mounted on the panel
through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is already
at least 18 years old), you will snap those thin little bits of plastic,
and your knob will be gone, and your scope will be unusable. Forget
about
gluing it, as there was barely enough strength with the virgin plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.

Tektronix did the same thing with their horizontal knobs, but they
knew enough about materials engineering to make the body of the knob
out of aluminum, and make the grip surface of the knob out of plastic.

I never had a HP scope that I liked, or would use unless there was no Tek
scope available.

 

[Chuck Harris]

Dave Edwards wrote:

Still using the 275Mhz hp1726A that was given to me when I started working
for HP in '83.
I keep it covered when not being used, so it still looks like new. Perhaps
some day it will crap out, and I'll try a Tek!!

I haven't seen that reliability is a problem with the 1726A. They go and
go... Drift is a bad problem, the zero goes all over the place, and needs
constant diddling. It is all but impossible to adjust so that the variable
volts/division knob doesn't shift the zero (and have it stay adjusted). The
horizontal time knob is a really bad problem, as I discussed in an earlier
note. If you haven't taken your scope apart, and oiled that switch's shaft,
and replaced the grease on the ball detent, I would strongly suggest that you
do so. When the knob breaks, it is end of game. I strongly considered turning
out the inside of one of the broken knobs, and making an aluminum version of
the center of the knob. The 1726A I wanted to fix was a complete cherry otherwise.
But, Tek scopes were so easy to find and so cheap, that I couldn't see any
real point. Into the scrap bin it went.

-Chuck

 

[Michael A. Terrell]

Richard Henry wrote:

I never had a HP scope that I liked, or would use unless there was no Tek
scope available.

Microdyne had shelves full of HP scopes, but most of the techs would
grab one of the beat up Leader 508A scopes.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Mark Moulding]

I've had a 545 (military version), and it was quite good, although it had
some calibration issues that I never really got resolved. Most of the time,
though, I just used my 475, up until a couple of years ago.

I got rid of the 454 (space reasons), and picked up an HP 54201D digital
scope with logic analyzer-type triggering. Although I haven't needed the
fancy triggering yet (though it would have been really helpful a couple of
times in the past), the scope itself has now become my main scope.

It's good to 300MHz (though I rarely need anything that fast), and I find
I'm using the on-screen measurement capabilities and storage abilities quite
a lot. Of course, the 475 is still sitting right on top, and in fact I used
it to fix a faulty input channel in the 54201D when I first bought it. But
really, the 475 rarely gets turned on now.

Oh - the best part was that the 54201D only cost me $50 at a Ham swap
meet...
--
Mark
"I prefer heaven for climate, hell for company."



"Richard Henry" <rphenry@home.com> wrote in message
news:424tgaF1h9oseU1@individual.net...

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:v4edneO2SYsvtCDenZ2dnUVZ_tqdnZ2d@rcn.net...
Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones,
but HP-1741A storage scope.

Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut two
(or was it 3?) slots that each cover 175 (115?) degrees through the body
of the knob.
They did that so that you could see the light mounted on the panel
through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is already
at least 18 years old), you will snap those thin little bits of plastic,
and your knob will be gone, and your scope will be unusable. Forget
about
gluing it, as there was barely enough strength with the virgin plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.

Tektronix did the same thing with their horizontal knobs, but they
knew enough about materials engineering to make the body of the knob
out of aluminum, and make the grip surface of the knob out of plastic.

I never had a HP scope that I liked, or would use unless there was no Tek
scope available.

 

[Mark Moulding]

Oh, and servicing the HP 54201D scope was pretty easy. It came apart in
obvious ways, and the boards were big, double-sided (not multi-layer), and
gold plated. There were a couple of scary-looking custom IC's, but the
problem in my case was just a burned-up 100 ohm resistor.

I eventually bought (rented and copied, actually) the operator and service
manuals for it, from W J Ford, who were quite easy to deal with and had a
*really* large stock of old manuals.
--
Mark
"I prefer heaven for climate, hell for company."

 

[Don Lancaster]

Michael A. Terrell wrote:

Richard Henry wrote:

I never had a HP scope that I liked, or would use unless there was no Tek
scope available.

The HP 130C was an excellent oscilloscope.
It has been stadily downhill from there.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[James Sweet]

Chuck Harris wrote:

Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones,
but HP-1741A storage scope.


Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut two
(or was it 3?) slots that each cover 175 (115?) degrees through the body
of the knob.
They did that so that you could see the light mounted on the panel through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is already
at least 18 years old), you will snap those thin little bits of plastic,
and your knob will be gone, and your scope will be unusable. Forget about
gluing it, as there was barely enough strength with the virgin plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.

Scrap? Surely a machinist could make a suitable replacement knob for
less than the value of a good scope.

 

[Chuck Harris]

James Sweet wrote:

Chuck Harris wrote:
Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones,
but HP-1741A storage scope.


Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut two
(or was it 3?) slots that each cover 175 (115?) degrees through the
body of the knob.
They did that so that you could see the light mounted on the panel
through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is already
at least 18 years old), you will snap those thin little bits of plastic,
and your knob will be gone, and your scope will be unusable. Forget
about
gluing it, as there was barely enough strength with the virgin plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.



Scrap? Surely a machinist could make a suitable replacement knob for
less than the value of a good scope.

You obviously haven't hired a machinist lately. In pristine shape, the
scopes were worth $75 tops, the machine shops charge $100/hour, 1 hour
minimum.

I was going to do the job myself, but balked because even when I was done,
all I would have was a bunch of scopes that no one wanted to buy. We had
them (with the broken/missing knobs in the $15 pile at several hamfests,
and they went nowhere.

-Chuck

 

[Too_Many_Tools]

"The HP 130C was an excellent oscilloscope.
It has been stadily downhill from there. "

I agree.

Why do you think that happened?

TMT

 

[Joel Kolstad]

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:scydnYswxt8O6yPeRVn-tg@rcn.net...

I was going to do the job myself, but balked because even when I was done,
all I would have was a bunch of scopes that no one wanted to buy. We had
them (with the broken/missing knobs in the $15 pile at several hamfests,
and they went nowhere.

And I imagine you'd already junked a few to use strictly as spare parts to fix
the others?

 

[Rich Grise]

On Thu, 05 Jan 2006 14:30:07 -0500, Dave Edwards top-posted:

Still using the 275Mhz hp1726A that was given to me when I started working
for HP in '83.
I keep it covered when not being used, so it still looks like new. Perhaps
some day it will crap out, and I'll try a Tek!!

Every now and then, one lucks out on a HP scope. For the most part, the HP
scopes I've used have been pretty marginal. There was one that was an
absolute nightmare, but that was a special case, because it was military,
and <oh, shit, apologies in advance> it was in a special case. <rimshot>
The knobs all had little waterproof rubber skirts, which had backlash that
makes ordinary backlash look like nothing at all. You had to go _WAY_ past
the setting you wanted, and hope that when the knob sprang back it would
land on the setting. I remarked to a coworker: "It probably wouldn't even
be a good boat anchor, because it would float."

I _did_ once use an HP that was tolerable.

But If I'm the one who signs the check,
my first choice, of course, would be a Tek.

Cheers!
Rich

"Richard Henry" <rphenry@home.com> wrote in message
news:424tgaF1h9oseU1@individual.net...

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:v4edneO2SYsvtCDenZ2dnUVZ_tqdnZ2d@rcn.net...
Atsunori Tamagawa wrote:

I own some scopes. Though, my favorite is not one of Tek ones, but
HP-1741A storage scope.

Hmmm? I cannot imagine what you like about the 1741A, but different
strokes for different folks.

Be very careful with that grey horizontal timing switch knob. HP cut
two (or was it 3?) slots that each cover 175 (115?) degrees through
the body
of the knob.
They did that so that you could see the light mounted on the panel
through
the knob. Well, when the switch's lubrication gets a little sticky,
and you get a little enthusiastic (and lord knows the plastic is
already at least 18 years old), you will snap those thin little bits
of plastic, and your knob will be gone, and your scope will be
unusable. Forget about
gluing it, as there was barely enough strength with the virgin
plastic.

We had dozens of that family of HP scope, and they all went into scrap
because
the knobs were unavailable.

Tektronix did the same thing with their horizontal knobs, but they
knew enough about materials engineering to make the body of the knob
out of aluminum, and make the grip surface of the knob out of plastic.

I never had a HP scope that I liked, or would use unless there was no
Tek scope available.

 

[Rich Grise, but drunk]

On Fri, 06 Jan 2006 09:16:45 -0800, Too_Many_Tools wrote:

"The HP 130C was an excellent oscilloscope.
It has been stadily downhill from there. "

I agree.

Why do you think that happened?

TMT

Because an oscilloscope isn't a Wein (Wien?)-bridge oscillator?

Thanks,
Rich

 

[Atsunori Tamagawa]

Rich Grise, but drunk wrote:

"The HP 130C was an excellent oscilloscope.
It has been stadily downhill from there. "

I agree.

Why do you think that happened?


Because an oscilloscope isn't a Wein (Wien?)-bridge oscillator?

No, they became short of CRT's because of their success in
network analyzer business, perhaps.

It seems that more people are having trouble with HP scopes
than I thought.
One has to treat scopes gently, just like treating women's body.
Instead of "pushing" buttons, one has to "touch" them.

Atsunori

 

[M. J. Powell]

In message <39KdnZtLUbvICiDeRVn-iQ@rcn.net>, Chuck Harris
<cf-NO-SPAM-harris@erols.com> writes

Dave Edwards wrote:
Still using the 275Mhz hp1726A that was given to me when I started
working for HP in '83.
I keep it covered when not being used, so it still looks like new.
Perhaps some day it will crap out, and I'll try a Tek!!

I haven't seen that reliability is a problem with the 1726A. They go and
go... Drift is a bad problem, the zero goes all over the place, and needs
constant diddling. It is all but impossible to adjust so that the variable
volts/division knob doesn't shift the zero (and have it stay adjusted). The
horizontal time knob is a really bad problem, as I discussed in an earlier
note. If you haven't taken your scope apart, and oiled that switch's shaft,
and replaced the grease on the ball detent, I would strongly suggest that you
do so. When the knob breaks, it is end of game.

May be relevant. When a plastic eyepiece on my father's WW I binoculars
shattered I found a company that made an exact copy from the other
eyepiece which I sent them. This was some twenty five years ago.

I don't know what the plastic was, possibly some form of Bakelite or
Ebonite.

Mike
--
M.J.Powell

 

[Tim Williams]

"Atsunori Tamagawa" <tamagawa@worldnet.att.net> wrote in message
news:43BEBFDA.2050907@worldnet.att.net...

One has to treat scopes gently, just like treating women's body.
Instead of "pushing" buttons, one has to "touch" them.

Well, no duh...I mean, which of these looks more like a 'scope?
http://webpages.charter.net/dawill/Images/Man-Woman.jpg

Tim

--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

 

[Chuck Harris]

Joel Kolstad wrote:

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:scydnYswxt8O6yPeRVn-tg@rcn.net...
I was going to do the job myself, but balked because even when I was done,
all I would have was a bunch of scopes that no one wanted to buy. We had
them (with the broken/missing knobs in the $15 pile at several hamfests,
and they went nowhere.

And I imagine you'd already junked a few to use strictly as spare parts to fix
the others?

That's just it, they all had the main knob broken. Some had the pieces intact,
but broken, others had nothing.

All worked, and all had the usual HP problems with drifty vertical amplifiers,
and easy to fool triggers. It wasn't worth fixing them. We also had dozens,
upon dozens of tek 465, 475, 485...

The tek scopes flew out, regardless of condition, the HP's just sat.

-Chuck

 

[James Sweet]

You obviously haven't hired a machinist lately. In pristine shape, the
scopes were worth $75 tops, the machine shops charge $100/hour, 1 hour
minimum.

I was going to do the job myself, but balked because even when I was done,
all I would have was a bunch of scopes that no one wanted to buy. We had
them (with the broken/missing knobs in the $15 pile at several hamfests,
and they went nowhere.

Well no I haven't hired one because friends of mine own a machine shop
so I can get favors like that for free but still, $75 tops? We're
talking a pretty decent scope aren't we? When I bought my Tek 465 a few
years ago I couldn't find anything 100MHz dual trace in working order
for under $275 or so.

 

[Ancient_Hacker]

Long ago I was given a summer job to repair a palletload of HP 1xx
scopes. One had a bad power transformer, unobtainable. The rest just
needed new power supply filter capacitors. They seemed like nice
scope, within their limits. Not particularly fast or bright or DC
stable, but okay for our biomedical lab. I think that one had an
actual knob on the DC balance control, it was so shaky.

I know this sounds like faint praise, but there's just something about
a scope without a fan, with nice big knobs that go click instead of
clunk, and that need no bandwidth limit button to keep the FM-ROCk-101
from fuzzing up the trace.

The HP 175 was an impressive scope-- 50+ 6DJ8's, 50MHz bandwidth, and a
super bright CRT. It just ran and ran up until 1995 when the
TRANSISTORS in the power supply went bad.

Still use a Tek 475 as my main bench scope.

Have tried several 54xxx digital scopes, don't care for the yucky green
or amber screens, or the infuriating menu structure, or the way they
don't detect clipping.

I have several Tek 485's on the to-repair shelf. IIRC they have about
six power supply voltages and if any one of them gets out of spec the
whole thing shuts down. Then it's kinda hard to figure out which one
went blooey first. Grrr....