Date   

Re: Uncal light on 453

Robert Morein <morepub@...>
 

If it's like other scopes, an uncal light is associated with a red vernier knob that isn't parked in the fully clockwise position, with a positive click.

----- Original Message -----
From: ko4nrbs
To: TekScopes@yahoogroups.com
Sent: Tuesday, January 13, 2004 8:40 AM
Subject: [TekScopes] Uncal light on 453


My 453's Uncal light is on. I saw something about this on a post but
can't find it now. I couldn't find any mention of it in the
operating manual. What does it mean and how do I get it to go out?
Thanks,
Bill Smith KO4NR



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New electrolyitc capacitors vs old ones

Bill Smith <ko4nrbs@...>
 

The capacitors manufactured today are much better than
the ones manufactured 10, 20 or 30 years ago. The
technological advances made in the materials used to
manufacture the capacitors provide you with an
excellent product. In addition they are usually much
smaller while having the same or higher voltage and
capacity ratings.

Within reason I always replace the electrolyitcs in
any old gear I buy. Especially in the power supply.
This is a good web site that explains the process:
http://antiqueradio.org/recap.htm

Thanks,
Bill Smith KO4NR

=====
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Uncal light on 453

ko4nrbs <ko4nrbs@...>
 

My 453's Uncal light is on. I saw something about this on a post but
can't find it now. I couldn't find any mention of it in the
operating manual. What does it mean and how do I get it to go out?
Thanks,
Bill Smith KO4NR


Re: Those old capacitor

Larry Coleman <bioengaust@...>
 

I have been sitting on the side line reading and enjoying the
postings on old electro's and your attemps to restore them.

I cound'nt resist any longer but I am not sure what you are trying to
do,From experiance I have developed a restoration proceedure when it
comes to restoring a vintage electronic device.
Step 1 replace all electro's where possible then look for obvious
faults.
Step 2 disconect the power suply and check voltages.
Step 3 connect supply with suitable resister and measure current draw
with low amp quick blow fuse.

As evil as the four steps are you can save a lot of heart ache.

Having worked for allied capacitors for a short time I know that
those electro's have a shelf life as the electrolite dries out and
the component becomes unreliable and possibly dangerous. As a person
who has lived through many explosions without shrapnal wounds watch
your eyes chaps,wear safety glasses if your face is close to the
component when powering up.
If you think you can rejuvinate them with any sort of reliability I
doubt if you will have any success,but if you are trying to make them
you are on the right track.
If you replace them with tantalums compare the performance data first.
Remember if a capacitor go's short circuit it can damage other
components worth more than a capacitor.
When the smoke gets out its very hard to put it back in, and IT can
come out with a big bang.

Anyway carry on you are developing some very interesting information
and I will see if I can find some data for you.

Good luck
Larry Coleman
Australia


Re: Dang'd old electrolytics again?

Robert Morein <morepub@...>
 

I had a 7904A that would not start up with a full load of plugins.
I removed the plugins, started up the scope, ran it for a couple hours.
I replaced the plugins, started it up, and ran it overnight.
No problems since.

It suggests to me that there was a cap seriously leaking in the power supply, that it managed to heal itself, by blowing off whiskers or reforming, and that it was, incredibly, a "good repair."

This doesn't happen often :).

----- Original Message -----
From: Howard Matthews
To: TekScopes@yahoogroups.com
Sent: Monday, January 12, 2004 9:30 PM
Subject: [TekScopes] Dang'd old electrolytics again?


Risking turning this group from a Tek scopes group to an
electrolytic capacitor group, I have questions.

I bought a "fixer" 454. Initial review showed chan 1 working okay,
but chan 2 not. After it sat a few months in my "shop", I started
working on it. First I checked and set all the voltage supplies.
They were all within spec, and now right on. However, now both chan
1 and chan 2 were visible ONLY using the beam finder. They were
both offscreen high.

So, I started tracing the voltage levels and signals in the chan 1
preamp first. A number of DC levels were off enough to throw the
trace off screen. And there was disturbing noise on top of the
signal. But before I could pin-point the source of the problem(s),
chan 1 starts working! It drifts around a bit, but the bias and
noise problems are gone.

Turning to chan 2 - guess what. After a few hours of trying to get
consistent readings and find the source of the problem, BINGO - chan
2 is working.

I left the scope powered off over night. The next day, both
channels are still working and now quite stable. No noise, no drift
after warmup.

The power supplies had and have NO problems. There are a number of
small bypass electrolytics in the preamp circuits which I did not
get around to checking.

Questions:
1. Is it likely that some electrolytics were "reformed" while I was
looking for the problem.

2. If so, is it likely the electrolytics will fail again soon, if
not used frequently? Might they have poor ESR, or high leakage now?

3. Should I pull the little electrolytics in the preamp and
check/replace them? I'm thinking modern tantalums might be good
replacements.

Anyone have similar experiences? Opinions? Advice?

TNX
-Howard





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Dang'd old electrolytics again?

Howard Matthews
 

Risking turning this group from a Tek scopes group to an
electrolytic capacitor group, I have questions.

I bought a "fixer" 454. Initial review showed chan 1 working okay,
but chan 2 not. After it sat a few months in my "shop", I started
working on it. First I checked and set all the voltage supplies.
They were all within spec, and now right on. However, now both chan
1 and chan 2 were visible ONLY using the beam finder. They were
both offscreen high.

So, I started tracing the voltage levels and signals in the chan 1
preamp first. A number of DC levels were off enough to throw the
trace off screen. And there was disturbing noise on top of the
signal. But before I could pin-point the source of the problem(s),
chan 1 starts working! It drifts around a bit, but the bias and
noise problems are gone.

Turning to chan 2 - guess what. After a few hours of trying to get
consistent readings and find the source of the problem, BINGO - chan
2 is working.

I left the scope powered off over night. The next day, both
channels are still working and now quite stable. No noise, no drift
after warmup.

The power supplies had and have NO problems. There are a number of
small bypass electrolytics in the preamp circuits which I did not
get around to checking.

Questions:
1. Is it likely that some electrolytics were "reformed" while I was
looking for the problem.

2. If so, is it likely the electrolytics will fail again soon, if
not used frequently? Might they have poor ESR, or high leakage now?

3. Should I pull the little electrolytics in the preamp and
check/replace them? I'm thinking modern tantalums might be good
replacements.

Anyone have similar experiences? Opinions? Advice?

TNX
-Howard


Re: 2215

Craig Sawyers <c.sawyers@...>
 

It is just as
expensive to ship something from Europe/UK over to the States.
It is horribly expensive to send stuff from the UK to the US. Taking a 30lb
package as a for instance, USPS tells me that this is $107 air parcel, and
$66 surface. The same weight by Royal Mail costs the same numbers in UK
pounds - �107 and �72 respectively. IOW it is 84% more expensive to ship
from the UK to the USA as it is in the other direction (on today's exchange
rate).

Craig

PS just been fighting another capacitor death problem. This time a shorted
tant in a Racal true RMS voltmeter. Took out the +15V reg too and a couple
of resistors. Tant was 47u 16V, on a 15V line. Posts to the list from
Miroslav indicates that this is sailing *very* close to the wind - so I'll
be changing out all dozen or so of these beasts now.

Racal volmeter is very interesting. Goes from 10kHz to 1.5GHz at 1mV full
scale max sensitivity. Does it with a random sampling probe, then analog
computer to calculate rms (squarer, integrator, log, halve then anti-log to
get square root). Accuracy 1% to 500MHz and 5% to 1.5GHz.


Re: 2215

Miroslav Pokorni
 

Do not think that Burma gets special treatment in shipping. It is just as
expensive to ship something from Europe/UK over to the States. Perhaps, hand
carrying the scope (as carry on-board luggage), when you go to the next
vacation might prove cheaper than to ship and certainly much better for the
health of the instrument.

Regards

Miroslav Pokorni

----- Original Message -----
From: "aakmoe" <aakmoe@yahoo.com>
To: <TekScopes@yahoogroups.com>
Sent: Monday, January 12, 2004 11:20 AM
Subject: [TekScopes] Re: 2215


Thanks Jeff

I saw one on uk ebay and I was wondering about it.
I have a 465B but I am thinking of getting a smaller & lighter scope.

I mean another one and may be ship back to Burma(Myanmar) so that I
can use when I go home on holiday.
Shipping costs from uk to Burma cost as much as a scope.

I am only a hobbyist and there don't have the full knowledge of
various models of tek scopes.
Scopes are really scarce in Burma outside the service centres and
government establishments.

Aung Moe








--- In TekScopes@yahoogroups.com, "Jeff W" <vwthingy@c...> wrote:
aakmoe wrote:

what do you think of 2215 scope.Is it 60Mhz any more information?
How does it compare to 465 series.
The 2215 (& 2213) were Tek's first foray into cheapie scopes. And
they made one, by gosh! They had a horrible power supply that used a
complex triac prereg scheme with current sensing, which didn't work
well & caused a loud 60Hz buzz from the smoothing choke. Tek
realized they screwed up, and released a modification kit that
replaced the prereg with a PWM switcher; a much better scheme. If
you are looking to buy a 2215, make sure it has this kit, or you will
think something is wrong with the scope from the loud buzzing noise
it will make. (the kit is no longer available)

I have a 2215 that I will sell really cheap, as it doesn't have this
kit :)

Yes; they are 60 Mhz bandwidth, but just that. I have worked on two
2215's, and both units barely met it, whereas most other Tek scopes
are rated more conservatively.

The 465 (especially a 465B) is a much better scope. You must keep in
mind that when the 2215 came out in 1982, it sold for $ 1,400, versus
the 465B which sold for $ 2,995 at that time. Bottom line: the 2215
sold for less than half the price of a 465B in 1982, it is less of a
scope then as now performance-wise, and usually sells for less today.

The only good thing about a 2215 is that it is fairly easy to work
on. Also, please keep in mind that the 2215A is better than the
2215; it uses the same mainboard & CRT as the 2235. (I had a 2215A
once and it was a nice little scope)

Jeff


Re: 2215

aakmoe <aakmoe@...>
 

Thanks Jeff

I saw one on uk ebay and I was wondering about it.
I have a 465B but I am thinking of getting a smaller & lighter scope.

I mean another one and may be ship back to Burma(Myanmar) so that I
can use when I go home on holiday.
Shipping costs from uk to Burma cost as much as a scope.

I am only a hobbyist and there don't have the full knowledge of
various models of tek scopes.
Scopes are really scarce in Burma outside the service centres and
government establishments.

Aung Moe

--- In TekScopes@yahoogroups.com, "Jeff W" <vwthingy@c...> wrote:
aakmoe wrote:

what do you think of 2215 scope.Is it 60Mhz any more information?
How does it compare to 465 series.
The 2215 (& 2213) were Tek's first foray into cheapie scopes. And
they made one, by gosh! They had a horrible power supply that used a
complex triac prereg scheme with current sensing, which didn't work
well & caused a loud 60Hz buzz from the smoothing choke. Tek
realized they screwed up, and released a modification kit that
replaced the prereg with a PWM switcher; a much better scheme. If
you are looking to buy a 2215, make sure it has this kit, or you will
think something is wrong with the scope from the loud buzzing noise
it will make. (the kit is no longer available)

I have a 2215 that I will sell really cheap, as it doesn't have this
kit :)

Yes; they are 60 Mhz bandwidth, but just that. I have worked on two
2215's, and both units barely met it, whereas most other Tek scopes
are rated more conservatively.

The 465 (especially a 465B) is a much better scope. You must keep in
mind that when the 2215 came out in 1982, it sold for $ 1,400, versus
the 465B which sold for $ 2,995 at that time. Bottom line: the 2215
sold for less than half the price of a 465B in 1982, it is less of a
scope then as now performance-wise, and usually sells for less today.

The only good thing about a 2215 is that it is fairly easy to work
on. Also, please keep in mind that the 2215A is better than the
2215; it uses the same mainboard & CRT as the 2235. (I had a 2215A
once and it was a nice little scope)

Jeff


125mF 450V Capacitor

wireless_paul <paul_earland@...>
 

Have a 545A Oscilloscope. There is a large metal electrolytic 125mF
450V capacitor in it. It has a leak and wants replacing. What and
where do I replace it with.
Thanks.
Paul


Cab-to-Rak adaptor for 5000 scopes

Tim Phillips <t.phillips@...>
 

Hi, all;
I have a couple of 5103Ns, one of which I would like to rack-mount.
Seems Tek once provided a kit of parts to adapt a 'boxed' 5xxx
to a rackmount. part# 040-0583-03. Anyone ever come across such
a thing? Never seen one on ebay.
Kindest regards
Tim.


Re: 2215

Jeff W <vwthingy@...>
 

aakmoe wrote:

what do you think of 2215 scope.Is it 60Mhz any more information?
How does it compare to 465 series.
The 2215 (& 2213) were Tek's first foray into cheapie scopes. And
they made one, by gosh! They had a horrible power supply that used a
complex triac prereg scheme with current sensing, which didn't work
well & caused a loud 60Hz buzz from the smoothing choke. Tek
realized they screwed up, and released a modification kit that
replaced the prereg with a PWM switcher; a much better scheme. If
you are looking to buy a 2215, make sure it has this kit, or you will
think something is wrong with the scope from the loud buzzing noise
it will make. (the kit is no longer available)

I have a 2215 that I will sell really cheap, as it doesn't have this
kit :)

Yes; they are 60 Mhz bandwidth, but just that. I have worked on two
2215's, and both units barely met it, whereas most other Tek scopes
are rated more conservatively.

The 465 (especially a 465B) is a much better scope. You must keep in
mind that when the 2215 came out in 1982, it sold for $ 1,400, versus
the 465B which sold for $ 2,995 at that time. Bottom line: the 2215
sold for less than half the price of a 465B in 1982, it is less of a
scope then as now performance-wise, and usually sells for less today.

The only good thing about a 2215 is that it is fairly easy to work
on. Also, please keep in mind that the 2215A is better than the
2215; it uses the same mainboard & CRT as the 2235. (I had a 2215A
once and it was a nice little scope)

Jeff


Single-sweep mod for 531/541

Tim Phillips <t.phillips@...>
 

Hi, all;
I have a 531A (with it's service manual), and
I recently saw on ebay what looked like a 531 with a
single-sweep feature added; (switch on front panel.)
Is this easy to implement? The photo I saw looked like
a genuine Tek mod, with a small photo-etched plate for the
switch.
kindest regards
Tim.


WANTED! 3L10 Spectrum analyser

petertech99h
 

Hi All,

I looking for a nice 3L10 analyser!!! They made them, they gotta be out
there!! Who can let one go??

Pls let me know!

Take care,

Peter


Looking for TG501 parts

eboytoronto
 

Hi,

Can anybody help ?

I am looking for a knob for the TG501 time marker generator.

I am also looking for a display board with the LEDs on it.

Thanks,

John Barnes


Re: What's the best manual?

maddisassembler
 

January 12th, 2004


Albert and all others who care for this issue,

even if one has a complete collection of
microfiche (which would be well above 10,000
microfiche I estimate) he would have to spend
appr. USD 2,000 (0.20 times 10,000) just to
have them digitized.

All this is worthless (or at least the same level
as putting microfiche into a reader) if this whole
action cannot give immediate answers to questions
like (just examples):
What is a 067-0542-99 good for? Where was part
120-0612-01 used and what was the serial number
range? Under which modification falls my 7A24
serial B116058?
etc etc etc

From my point of view such answers can only be
found in reasonable time if the contents of all
microfiche are linked into some kind of data base
or retrieval system.

To build up such a system it would need a big
effort of labour - too much for single a person
with only 24 hours a day to spend on this...

Comments welcome.

Best regards
-Roland



--- In TekScopes@yahoogroups.com, "Albert LaFrance" <lafrance@a...>
wrote:
Another option which might be worth considering is to have the
microfiche
scanned onto a CD-ROM. I looked into this a while ago for some
Bell System
Practice manuals, and several service companies estimated prices of
15-35
cents per image, depending on quantity, fiche quality, need for
post-scanning image cleanup, etc.

Albert

----- Original Message -----
From: "Stan & Patricia Griffiths" <w7ni@e...>
To: "maddisassembler" <320041677522-0001@t...>
Cc: "TekScopes" <TekScopes@yahoogroups.com>
Sent: Monday, November 03, 2003 4:43 PM
Subject: [TekScopes] What's the best manual?


<SNIP>
Our local library has microfiche readers that can read either
fiche sheets
or 35mm filmed images and convert any image to hard copy on
excellent copy
paper similar to what you use in your own laserjet printer. It
costs 10
cents per image to do prints and I sometimes use that service.
<SNIP>


Re: tek 475 sweep probleem

benclarke_uk
 

Hi Henny
I have just fixed a 465 with a very similar problem, in my case certain
sectors of the timebase control would produce a sweep whilst other sectors
would not.
The problem turned out to be the Zener that feeds the negative supply to
the Monolithic Sweep Control IC going short circuit. The IC needs +5v and
-5v but the scope only has +5v and -8V available. The negative supply is
therefore derived from the -8v line by feeding it through a 3v Zener. With
-8v instead of -5v the IC would work happily on certain ranges, but not at
all on others.
The 475 and 465 circuitry is identical in the area that failed so it may be
worth a check on your unit.
Cheers,
Ben

At 18:42 08/01/04, hi1vld wrote:
I just bought this scope, but have the following problem:
Wen using the scope with a setting of 1ms or shorter, i got a trace.
But when using 2ms and longer i got no trace.
What could be the problem?
I have a service manual, but don't know were to begin.
I will start with measuring the voltages from the supply, but when i
take the scope appart, i also want to look at this sweep problem.

Thank you.

Henny



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2215

aakmoe <aakmoe@...>
 

HELLO ALL

what do you think of 2215 scope.Is it 60Mhz any more information?
How does it compare to 465 series.

thanks

AKM


Re: tek 475 sweep probleem

Stan & Patricia Griffiths <w7ni@...>
 

Hello Henny,

Here is place to start on your 475 after you are certain the power supplies
are working correctly.

Go to the Timing Switch schematic diagram and look for changes that occur
when you switch from 1 ms to 2 ms, like a part that is switched in the
circuit right at that point.

That is where I would start on this problem.

Stan
w7ni@easystreet.com

----- Original Message -----
From: "hi1vld" <intersound@zonnet.nl>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, January 08, 2004 10:42 AM
Subject: [TekScopes] tek 475 sweep probleem


I just bought this scope, but have the following problem:
Wen using the scope with a setting of 1ms or shorter, i got a trace.
But when using 2ms and longer i got no trace.
What could be the problem?
I have a service manual, but don't know were to begin.
I will start with measuring the voltages from the supply, but when i
take the scope appart, i also want to look at this sweep problem.

Thank you.

Henny




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To visit your group on the web, go to:
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Re: Fuzzy 465B trace revisited, final report

donlcramer@...
 

This is follow up for posts made about a year and half ago (has it been that
long?) asking for help with an odd behaviour, fat-ish trace on a 465B of
vintage B048 SN prefix. See posts #2024, #2008 and related for additional details
of the symptoms.

I'd run the scope by an ex-Tek CRT inspector, and she thought the symptoms
looked like "low cathode". I interpreted this to mean that, although emission
is still good, it is coming predominantly from parts of the cathode structure
that are not optimum for a nicely focused beam. Another CRT related
possibility mentioned at the time was some kind of mechanical damage that affected the
internal alignment of the elements. Whatever the root cause, it turned out the
problem was indeed with the CRT itself, and not the electronics. A new CRT
(actually for a 465M) from ebay, a new blue filter from Walter at Sphere
Research, and a recal, and it seems to be as good as rain again. With the new tube,
the traces are nicely crisp. Not as good as I remember a 485 mind you, but
quite nice, and certainly not worse than any other common Tek scope of the 80's
and 90's that I'm familiar with.

Don Cramer
Beaverton, OR

178581 - 178600 of 184777