Watson's Weston Meter Mystery

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message unavailable

 

[gothika]

On Mon, 8 Mar 2004 23:10:55 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

"gothika" <Vampyres@nettaxi.com> wrote in message
news:afjq40do9a1li9tdfdtcc49n8nhr1bc7em@4ax.com...
[snip]

WHOA! I'm watching the news and the weatherman said it was 97 deg F
(36
deg C) in downtown Santa Banana - a new record! I went outside at
lunchtime after being in the cold computer room, and it was kind of
like
opening an oven door: the wall of heat sort of hit. But it was a
really
beautiful day, even tho it was a bit toasty.

97 a bit toast? Heck that aint even warm. Try 103 with 98% humidity.
I seem to recall a few days last summer when we reach 106.

But it's not even spring yet! It's still 'winter'! It's March 8!
Dontcha get it? 97 degrees in March!!



You're talking Santa Barbara right? Yes that would be a bit high for

this time of the year for your local. But not terrible, try some
place like Stampede Pass where it's freezing cold most of the year and
a typical snow fall is 15ft or more.
Go hang out at the beach or take a cruise down PCH on a skooter.
Your weather will probably level out and you'll be enjoying those mild
summers SoCal is so famous for.

 

[gothika]

On Tue, 9 Mar 2004 00:29:21 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

"Robert Baer" <robertbaer@earthlink.net> wrote in message
news:404AE249.5DDAA8AD@earthlink.net...
"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:

Watson's Weston Meter Mystery

Help me solve this Weston Meter Mystery. I got this good ol' Weston
Voltmeter at the Antique Telephone Collectors Ass'n show this
weekend,
and it works great on the 3V range. I want to do a little
modifying.
It has three binding posts on the top, 3V, 150V and 300VDC. I want
to
change the resistors on the 150 and/or 300VDC ranges to make them 15
and/or 30VDC. I took the four corner screws out but the case won't
budge. I've attached a pic of it, with the enlarged screwhead that
maybe isn't a screw head, or whatever, and posted it to ABSE. Maybe
someone has had experience with getting these apart. Thanks for any
info.

I have a Weston Microammeter, and the trick to it was to remove the
binding post knobs on the face (meter surface), the range switch on
the
face, then the screws on the back (the zeroing knob remained as a part
of the case), then remove the screws on the back.
In your case, look for "standoff" bumpers on the back and see if
there
are screws hiding underneath.
Seems to me that the back should come off; look for a parting line.

Also carefully and with minimal force, pry it apart when all screws
(except for the "W" screws) are out, to see where the resistance
point(s) may be - in other words, does it seem that the "W" points are
holding?
If it seems that the "W" points are the only remaining fasteners,
try
(a) soak 8 HR+ with lubricating screw-removal liquid (forget the name
now and too lazy do dig it out), (b) make a mold of the head and from
that mold, a screwdriver (plastic or low MP metal to form in mold).
Align the home-made scerwdriver and tap lightly with with hammer (to
help loosen scerw) while turning.
This might work well enough to keep the head shape intact, even if
of
plastic.
Worst case is to break the plastic "W" off and drill the head off;
replace with a screw that has a head that matches the others.

After J.W. clued me in earlier this evening (see followup), I dug the
pitch out of the screw heads with an exacto knife. I got most of it out
and then unscrewed the screws. The cover came off front of the case
easily. But the problem is that the meter is mounted to the case, and
there is nothing protecting the meter movement including the needle, so
one false move, and total catastrophe!

I looked behind the movement and saw the three bobbins that hold the
resistance wire, and how they're connected between the binding posts.
They're connected in series, like this. View with courier font.


3V 150V
o o
| |
- o----[Meter]-----/\/\/\---+----/\/\/\---+----/\/\/\-----o + 300V
R1 R2 R3


Since it's 1000 ohms per volt, the R1 and meter resistance is 3000 ohms.
The other two resistors are about 150k each, but they are not equal, and
they were marked with "150" and "300" when it was put together decades
ago.

Since getting to the bobbins requires that the meter movement be
removed, and I've meddled with and fouled up more than one meter
movement in the past, I'm not going to risk messing this one up, so I
put it back together.

I've decided that the best way to make the mods is to unscrew the four
binding post nuts, put a piece of glass epoxy PCB with four holes in it
over the four screws, and then put the binding post nuts back on. I'll
mount all the resistors on this PCB. I can even put 4 four-way binding
posts on the PCB so it will allow me to use banana plugs for the test
leads.

If I could find one, I could mount a single pole, three position slide
switch on the PCB so I can select the three ranges. Or else just KISS
and just use the binding posts for choosing the ranges, like it is at
present.

That meter movement is unbelievable! It has the mirror behind the
needle to avoid parallax. I connected it to the Power Designs 2005
precision voltage source to see how accurate it was. The 2005 has four
ten-step rotary range switches, one each for volts, tenths, hundredths,
and thousandths of a volt, and a vernier pot that varies it by 1000
microvolts, same as 1 millivolt.

I set it for 3.000 VDC, and varied the vernier pot by 0 to 1000
microvolts. The meter needle is very thin, less than a third of the
black line on the meter scale that indicates 3 volts. Using a
magnifying glass, I can *easily see* the meter needle moving across the
black line maybe a quarter of the line width! I can actually see it
moving as I vary the pot by a few hundred microvolts! Wow! A wiggle
stick meter than can resolve a change of microvolts!

Now I know why those old Wheatstone bridges used a galvanometer with a
needle that cast a shadow on an illuminated scale, and using mirrors,
the light path was lengthened to maybe several feet in a small case. So
it allowed the ever so tiny meter needle movements to be magnified and
easily seen on the scale.

Someone insert a URL with pictures here explaining these old galvos, and
how they worked. It's late and I'm getting bleary-eyed.



I started out my photographic carreer using those old Weston light

meters and never got a bad reading once. Those things were built like
tanks.

 

[Michael Varney]

"Netvision" <abce98@netvision.net.il> wrote in message
news:c27q56$j55$1@news2.netvision.net.il...

Can anyone send me a 4-bit binary divider circuit in this email :
abce98@netvision.net.il

I must make this homework for my university and i
am late.
PLEASE HELP !!!!!!!!!

Thanks a lot

Now that it is several days later, all I can hope is that since you refused
to do your own thinking, you were graded accordingly.

 

[gmv]

"Daniel Rudy" <dcrudy@invalid.pacbell.nospam.net.0123456789> Typed in message
news:wyf3c.21629$tG4.5957@newssvr29.news.prodigy.com...

And somewhere around the time of 02/17/2004 10:56, the world stopped and
listened as news2020 contributed the following to humanity:

Brain Injury By Lasers Again While Sleeping
---------------------------------------------

Lasers from neighboring houses have again been shot
at my head while sleeping, causing brain injury - felt
as pain along the line where the laser hits. The line is
along the cheekbone, somewhat like decapitating or
lobotomy.

The laser sources are all around - #1290 neighbor is
serving as the computer control center for most of the
activity. #1291, #1295 neighbors on both sides are
most certainly active participants in the injuries. #1051
chimney laser is one of the deadliest ones in use.

I moved sleeping locations from upstairs to garage
inside my protected car to avoid further brain injury.
But, there too #1290 computer controlled lasers
and #1296 and other sources were used to hit me
in the kidneys, back of the neck, head from the
top and sides, heart, etc. and induce sleep as well
as run hypnotic sessions. These lasers are used to
keep me in sleep state until the 'killers' decide to
allow me to wake up (eg. at 1 am or 5 am etc.).

There is no change in the killers. They are continuing
their fearless high crimes as if no one can do anything to
stop them.

----------------------------------------------------

This is not all. Last night nuclear radiation was spewing
out of the flower pot on #1291 deck causing
burning all over the body. In addition, cars in the
Los Esteros parking lot seemed to be controlling
cars and devices in our community to send electrocuting
beacons at me all afternoon.

------------------------------------------------------

True paranoia and skitzaphrenia are treatable diseases. You will need
to talk to your psychologist for treatment options though.

Psychiatry and Psychology are the only true enemies of freedom.

--
Daniel Rudy

Remove nospam, invalid, and 0123456789 to reply.

 

[Watson A.Name \"Watt Sun]

Robert Baer wrote:

"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:
[snip]

After J.W. clued me in earlier this evening (see followup), I dug the
pitch out of the screw heads with an exacto knife. I got most of it out
and then unscrewed the screws. The cover came off front of the case
easily. But the problem is that the meter is mounted to the case, and
there is nothing protecting the meter movement including the needle, so
one false move, and total catastrophe!

I looked behind the movement and saw the three bobbins that hold the
resistance wire, and how they're connected between the binding posts.
They're connected in series, like this. View with courier font.

3V 150V
o o
| |
- o----[Meter]-----/\/\/\---+----/\/\/\---+----/\/\/\-----o + 300V
R1 R2 R3

Since it's 1000 ohms per volt, the R1 and meter resistance is 3000 ohms.
The other two resistors are about 150k each, but they are not equal, and
they were marked with "150" and "300" when it was put together decades
ago.

Since getting to the bobbins requires that the meter movement be
removed, and I've meddled with and fouled up more than one meter
movement in the past, I'm not going to risk messing this one up, so I
put it back together.

I've decided that the best way to make the mods is to unscrew the four
binding post nuts, put a piece of glass epoxy PCB with four holes in it
over the four screws, and then put the binding post nuts back on. I'll
mount all the resistors on this PCB. I can even put 4 four-way binding
posts on the PCB so it will allow me to use banana plugs for the test
leads.

If I could find one, I could mount a single pole, three position slide
switch on the PCB so I can select the three ranges. Or else just KISS
and just use the binding posts for choosing the ranges, like it is at
present.
[snip]

Yes...all of them are that way; zero meter protection when apart.
And the accuracy is not a pecentage of full-scale like "modern"
analogs, the accuracy is a percentage of the reading *anywhere*; meaning
!superb!.
I bet that (approximately) that R3=R1+R2 and that is why R3 is not
equal to R2.

Yeah, Zackly. But oddly, they're not some even value like I had
supposed. They are something like 149. something k and 152. something
k. The DMMs I'm using don't do such a good job of resolving on the 200k
range.

Have an alternate idea: leave the meter alone and use external
resistors from the 3V terminal.

Um, isn't that what I said I was gonna do?? Above..

What I had to do was calculate the right values for the shunts. The
only problem is that I've already put a 1% fixed resistor and pot across
the 150 V resistor, and then set it to give the correct reading. I then
measured it, and it doesn't match up with the calculations. So I'll
probably just leave it so it's slightly adjustable.

The 150V resistor has 147V across it at FS. That means that for a 1 mA
meter, it should be 147k. But it measures 149. something k. Weird.

 

[Watson A.Name \"Watt Sun]

gothika wrote:

On Mon, 8 Mar 2004 23:10:55 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

"gothika" <Vampyres@nettaxi.com> wrote in message
news:afjq40do9a1li9tdfdtcc49n8nhr1bc7em@4ax.com...
[snip]

WHOA! I'm watching the news and the weatherman said it was 97 deg F
(36 deg C) in downtown Santa Banana - a new record! I went outside at
lunchtime after being in the cold computer room, and it was kind of like
opening an oven door: the wall of heat sort of hit. But it was a
really beautiful day, even tho it was a bit toasty.

97 a bit toast? Heck that aint even warm. Try 103 with 98% humidity.
I seem to recall a few days last summer when we reach 106.

But it's not even spring yet! It's still 'winter'! It's March 8!
Dontcha get it? 97 degrees in March!!

You're talking Santa Barbara right?

No, I'm talking about a few miles down the road from Disneyland.

Yes that would be a bit high for
this time of the year for your local. But not terrible, try some
place like Stampede Pass where it's freezing cold most of the year and
a typical snow fall is 15ft or more.
Go hang out at the beach or take a cruise down PCH on a skooter.
Your weather will probably level out and you'll be enjoying those mild
summers SoCal is so famous for.

All the heat blew out to sea, so it's hot at the beach! The problem is
that there are a whole lotta people at the beach and very few
lifeguards, and people are getting caught in still really cold water,
and there have been a lotta rescues.

Ya don't have to tell me what it's like to be hot and humid. In the
army I was stationed a few blocks from the Mississippi river in the
summertime with no a/c. Damn mosquitoes!

 

[DarkMatter]

On Mon, 08 Mar 2004 11:59:23 -0500, JW <none@dev.nul> Gave us:

On Sat, 06 Mar 2004 03:48:13 -0800 DarkMatter
DarkMatter@thebarattheendoftheuniverse.org> wrote in Message id:
ejej409cc01mnjq3a6rrq6jepsff8v3por@4ax.com>:

On Sat, 06 Mar 2004 03:48:24 GMT, news2020 <user121@peoplepc.com> Gave
us:

The techniques are changing and the people
are constantly being brought in to keep the
electrocution and injuries going.

You're a fucking Usenet trolling retard.

Pot? Meet the black kettle.

You're an idiot.

Oh look! I have a new puppy dog troll!

 

[Jim Thompson]

On Tue, 09 Mar 2004 07:51:41 -0800, "Watson A.Name \"Watt Sun - the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

gothika wrote:

On Mon, 8 Mar 2004 23:10:55 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:


"gothika" <Vampyres@nettaxi.com> wrote in message
news:afjq40do9a1li9tdfdtcc49n8nhr1bc7em@4ax.com...
[snip]

WHOA! I'm watching the news and the weatherman said it was 97 deg F
(36 deg C) in downtown Santa Banana - a new record! I went outside at
lunchtime after being in the cold computer room, and it was kind of like
opening an oven door: the wall of heat sort of hit. But it was a
really beautiful day, even tho it was a bit toasty.

97 a bit toast? Heck that aint even warm. Try 103 with 98% humidity.
I seem to recall a few days last summer when we reach 106.

But it's not even spring yet! It's still 'winter'! It's March 8!
Dontcha get it? 97 degrees in March!!


You're talking Santa Barbara right?

No, I'm talking about a few miles down the road from Disneyland.

Yes that would be a bit high for
this time of the year for your local. But not terrible, try some
place like Stampede Pass where it's freezing cold most of the year and
a typical snow fall is 15ft or more.
Go hang out at the beach or take a cruise down PCH on a skooter.
Your weather will probably level out and you'll be enjoying those mild
summers SoCal is so famous for.

All the heat blew out to sea, so it's hot at the beach! The problem is
that there are a whole lotta people at the beach and very few
lifeguards, and people are getting caught in still really cold water,
and there have been a lotta rescues.

Ya don't have to tell me what it's like to be hot and humid. In the
army I was stationed a few blocks from the Mississippi river in the
summertime with no a/c. Damn mosquitoes!

It was 101°F on my patio yesterday, but humidity was 15%.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Will you still need me, will you still feed me, when I'm sixty-four?

 

[Jim Yanik]

"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in
news:c2l1ar$qq0$0@216.39.172.65:

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns94A6E0FBD4958jyanikkuanet@204.117.192.21...
Jay Levitt <jay+news@jay.fm> wrote in
news:MPG.1ab6a73d788d1043989729@news-central.giganews.com:

[...]
I'd pay $100 for it.. but how do you keep the calibrator
calibrated?


Good quality DMM and a freq.counter locked to WWVB.
I don't believe one could be made for sale at $100 and still make a
profit,though.Maybe $200.

Why would that level of accuracy be necessary? I'd think that +/-1%
accuracy on time and voltage would be more than enough, for an
amateur-level (or even pro-level) calibrator. But I'm ignorant of
this!

The rule is 4X better accuracy than the unit under test.Since most scope
timebases are 3%(2445/65 is 1.25%!),youneed at least 0.75%.Since canned
clock oscillators are much better than that(100ppm),there's no problem.

Getting 1% timebase stability should be darn easy. Even if there was
long-term drift, you'd just need a "counter" mode where you time it
for five minutes and then adjust to get the right count. One second
is 0.3% of five minutes, and a wristwatch with a second hand will be
plenty accurate. No need for a WWV* receiver.

Well,you want to check against gross errors,most freq counters would
suffice.But since hobbyists have no way of knowing if their counters are
accurate(within spec),locking to WWVB is fairly easy and very accurate.

I'm not sure about the voltage. I think I can make an accurate low
voltage square-wave at low frequencies, based on gating a bandgap
reference; and I could probably get that up to 10MHz or so. I don't
know if the same approach would work for 100MHz. And I'm not sure how
I'd calibrate the highest-voltage scales.

I'm just brainstorming; I've never even seen a scope calibrator, I
don't know what they do or what the issues are. Anyone care to chip
in?

TEK's PG506 has a fast rise output for freq.compensation and leading edge
cal,>1ns at 0-1vPP into 50 ohms,100 Hz-1Mhz in decade steps,then it has a
hi-amplitude output,0-60V,for adjusting attenuator comps,also 100Hz-
1Mhz,and the standard amplitude output,5mv-100V (into 1MegR)1Khz sq.wave
for amplitude cal of the attenuators.(in 1-2-5 steps)
Then there's the TG501 timemark generator,1ns to 5sec(IIRC) for timebase
cal,then there's the SG503 leveled sinewave generator,50Khz to 250 Mhz.for
freq.response verification.

That's was TEK's cal package for scopes to 250Mhz.

--
Jim Yanik
jyanik-at-kua.net

 

[Jim Yanik]

Jim Adney <jadney@vwtype3.org> wrote in
news:20gq405sm96d89n2q18qqfi7k7sp3oeh30@4ax.com:

On Mon, 8 Mar 2004 11:57:02 -0500 Jay Levitt <jay+news@jay.fm> wrote:

Also, given that folks are recommending calibrating even hobbyist scopes
every few years, it seems like I wouldn't particularly gain much by
buying a calibrated scope.

Unless you're doing very precise work, there's seldom a need to
recalibrate any Tek scope. I've had bits and pieces of mine stop
working, but they've never gone out of calibration that I can tell.

There's the key;"that you can tell".That's why there's calibration;to
VERIFY that the readings are within specs.

An inexperienced hobbyist may get very confused if his scope had response
problems,or was not reading the correct amplitude at some attenuator
settings,or the wrong timing on -some- ranges.

--
Jim Yanik
jyanik-at-kua.net

 

[Mark Fergerson]

news2020 wrote:

Ok. Ok. No negatives acknowledged.

You're welcome. I think.

I'll keep quiet and wait until your corner reflectors rip up
or something. Then Mark will be hunting up libraries and
poor harassed librarians. There's still time for Mark.
I'll wait as the clock keeps ticking.

I haven't personally lined my living spaces with corner
reflectors as I don't need them. I told you last year that
part of your problem is that so few others have had your
experiences. I haven't, so I haven't had to do anything
about them.

As I see it there are four possibilities:

1. You may be living in the path of intermittent unintended
transmissions all over the spectrum at all kinds of power
levels from who knows what kinds of sources like airport or
military beacons, cellphone towers, weather radar, and the like.

I'd know what to do about that, namely document the
signals' timing, frequencies, directions and power levels,
then aim a lawyer or three at the offenders.

2. You may be the victim of deliberate clandestine attacks
as you believe.

I'd know what to do about that too, namely detect the
signals etc. and shield against them or return to their
source all that I could (assuming enough lawyers tell me
they don't want to get involved).

3. You may be delusional, but until you gain enough
technical competence to eliminate the first two
possibilities, you cannot know for certain. Hence you're
going to get little but derision from people competent to
test 1&2.

I wouldn't know what to do about #3 except try to
suppress my paranoia long enough to get into therapy.

4. I (and possibly others here) may be, or may have been in
the past, the victim(s) of the same kind of attack as you
claim, but we're just not adequately susceptible so the
attackers got bored and looked for easier meat.

You're the only one in a position to do anything about
this. Do you want to accept the responsibility and do the
work necessary to find out what's really going on? It's your
choice. Nobody but you has the power to make that decision
and follow up on it.

Mark L. Fergerson

 

[ns]

There is another option here: he is pulling your leg.

"Mark Fergerson" <nunya@biz.ness> wrote in message
news:y4n3c.188$Nj.65@fed1read01...

news2020 wrote:

As I see it there are four possibilities:
1.
2.
3.
4.

 

[Tobin Fricke]

On Mon, 8 Mar 2004, Aidan Grey wrote:

Try posting your questions on the newsgroup:
natinst.public.gpib.general

Thanks for the reference... is there a special NI news server? That group
is outside of the normal usenet hieararchy (at least I don't get it here).

Tobin

 

[Kevin Carney]

I don't know where they got the IC from. They were only available for Tek
service centers about 5 years ago. 3 to 4 years ago the service center would
not repair one we sent in because they were no longer available. I would
check with them and be certain they have the IC before sending it in.

--
change .combo to .com for correct email

***************************************************
"We ought always to know precisely why a given job
is done in a particular way, and why it is done at
all, and why it can't be done more efficiently,
if it must be done at all."-- T.J.Watson

***************************************************

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns94A663F28AD99jyanikkuanet@204.117.192.21...

"George Kerber" <glkinst@earthlink.net> wrote in
news:uVP2c.27150$aT1.13875@newsread1.news.pas.earthlink.net:

Thanks for all of the comments. I found a person in LA that can repair
these scopes and replace the 155-0242-02 for a reasonable price. I am
going to try out the service next week. I wonder if there is a good
market for a reversed engineered replacement using surface mount parts
and a small multilayer PC board instead of the IC?
George Kerber


It's been discussed before,IIRC on sci.electronics.design.I suppose it
could be done,but the market is pretty small,so the cost per unit would be
high.
TEK packed a lot into that IC,and there's not much available space around
the IC footprint on the motherboard.I also suspect linearity at the
fastest
sweep speeds would be a problem.



--
Jim Yanik
jyanik-at-kua.net

 

[Aidan Grey]

On Tue, 9 Mar 2004 10:34:36 -0800, Tobin Fricke wrote:

On Mon, 8 Mar 2004, Aidan Grey wrote:

Try posting your questions on the newsgroup:
natinst.public.gpib.general

Thanks for the reference... is there a special NI news server? That group
is outside of the normal usenet hieararchy (at least I don't get it here).

Tobin

I don't know if they have a news server as such. You can submit a
question through:

http://sine.ni.com/apps/we/niae_asc.main

It is also possible to search the NI discussion forums for a particular
topic.


Aidan Grey

 

[Watson A.Name \"Watt Sun]

Jim Thompson wrote:
[snip]

It was 101°F on my patio yesterday, but humidity was 15%.

...Jim Thompson

Yabbut.. That's Arizona! Like the peak temps for So. Calif are the
mean or average for Phoenix!

 

[Jim Thompson]

On Tue, 09 Mar 2004 12:51:06 -0800, "Watson A.Name \"Watt Sun - the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:

Jim Thompson wrote:
[snip]


It was 101°F on my patio yesterday, but humidity was 15%.

...Jim Thompson

Yabbut.. That's Arizona! Like the peak temps for So. Calif are the
mean or average for Phoenix!

AND we don't get the severe humidity like you do. 90°+ in the LA
basin in bad-ass.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

Will you still need me, will you still feed me, when I'm sixty-four?

 

[George Kerber]

The horizontal output ICs are probably pulls from older scopes and,
hopefully, more reliable than the later versions. I have an older 2445 that
has the same IC and its been working fine for many years.
George Kerber


"Kevin Carney" <carneyke@us.ibm.combo> wrote in message
news:c2l69g$ikk$1@news.btv.ibm.com...

I don't know where they got the IC from. They were only available for Tek
service centers about 5 years ago. 3 to 4 years ago the service center
would
not repair one we sent in because they were no longer available. I would
check with them and be certain they have the IC before sending it in.

--
change .combo to .com for correct email

***************************************************
"We ought always to know precisely why a given job
is done in a particular way, and why it is done at
all, and why it can't be done more efficiently,
if it must be done at all."-- T.J.Watson

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"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns94A663F28AD99jyanikkuanet@204.117.192.21...
"George Kerber" <glkinst@earthlink.net> wrote in
news:uVP2c.27150$aT1.13875@newsread1.news.pas.earthlink.net:

Thanks for all of the comments. I found a person in LA that can repair
these scopes and replace the 155-0242-02 for a reasonable price. I am
going to try out the service next week. I wonder if there is a good
market for a reversed engineered replacement using surface mount parts
and a small multilayer PC board instead of the IC?
George Kerber


It's been discussed before,IIRC on sci.electronics.design.I suppose it
could be done,but the market is pretty small,so the cost per unit would
be
high.
TEK packed a lot into that IC,and there's not much available space
around
the IC footprint on the motherboard.I also suspect linearity at the
fastest
sweep speeds would be a problem.



--
Jim Yanik
jyanik-at-kua.net

 

[Jim Adney]

On Mon, 8 Mar 2004 11:57:02 -0500 Jay Levitt <jay+news@jay.fm> wrote:

Also, given that folks are recommending calibrating even hobbyist scopes
every few years, it seems like I wouldn't particularly gain much by
buying a calibrated scope.

Unless you're doing very precise work, there's seldom a need to
recalibrate any Tek scope. I've had bits and pieces of mine stop
working, but they've never gone out of calibration that I can tell.

-
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Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
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