I'm one of those "Why is this not working. I must tear it apart, try to fix it, ask a million questions to the various email lists, eventually find the problem, and move to the next thing" people.

Those xstrs are a bit high priced but I suppose if they work then...

Thanks,
Barry - N4BUQ

Yea, but I am one of those, "Why is this working? I must tear it
apart to find out why!" people.

The original parts are available:

http://www.talonix.com/shop/item.aspx?itemid=10699

Thanks,
Barry - N4BUQ

At least with the older Magnestat Wellers, the individual parts are
readily available so used ones may be refurbished.

Oops, accidently sent that before I finished.

The 455/465M uses an improved version of this circuit with a fast (50
MHz) D44H11 type of transistor but it is not clear to me what changed
to allow this. Maybe the transformer is better?

If I get my hands on one of the 465 series oscilloscopes, I will test
it to see what would be neccessary for a more commonly available
transistor to work.

The 455/465M uses an improved version of this circuit with a fast (50
MHz) D44H11 type of transistor but it is not clear to me what changed
to allow this. Maybe the transformer is better?

If I get my hands on one of the 465 series oscilloscopes, I will

In this thread the 151-0140-00 transistor was mentioned as also being
used in scopes like the 7603, and I had the same experience Fabio had
where nothing except a homotaxial RCA 2N3055 would work as a replacement
in a 7603.
I think I found out about the importance of using a homotaxial 2N3055 on
the Tekscopes Group and was able to buy some from Surplus Sales of
Nebraska who had a few of them at the time (10 or more years ago?).
It looks like Walter at Sphere Electronics may have some of them in stock.
There are lots of TO-3's that are claimed to be the same or better than
the RCA 2N3055 homotaxial, and I tried many of them with no luck.
If one had enough circuit knowledge they might be able to modify the
circuit to use a modern 2N3055... but that is... and was, way beyond my
ability.
tom jobe...

On 11/1/2017 3:06 PM, Fabio Trevisan fabio.tr3visan@gmail.com
[TekScopes] wrote:

Hello Joe,
I have a 464 which had problems with the HV circuitry when it got to me.
The H.V inverter of the 464 is VERY, VERY similar to yours (it's basically
the same circuit).
In the process of solving my primary problem (which was in the H.V.
transformer... not necessarily your case) I got my original tek part
151-0140-00, a "selected" 2N3055 burned.

What brought me to writing to you is only to emphasize FURTHER (others
already pointed it out) that the 2n3055 (Q1418) in this circuit is REALLY
critical.
When my original got burnt, from about 5 or 6 different 2n3055 I
tried, the
circuit only worked with one of them, and still, I needed to change the
value of a resistor, to lower a little bit its base drive current.
The one that worked on my case was the MJ15015 (Which David Hess mentioned
earlier and which he added to his list because of my case).
I tried the 2n3772 and it oscillated at an harmonic of the transformer
characteristic frequency (I think 3rd or 5th harmonic, don't remember
now).
Curiousby itslef because exactly the 2n3772 has a low Ft of 200KHz, the
lower of all.
I even thought it was a fake, but I opened it up later on and it was
clearly an original part (mine was from ST).
I tried to buy from a local auction site a vintage RCA 2n3055, dated
something around 1969 (markings where too faded away). I`m not sure it's a
Hometaxial part as the original tek part is, but this one didn't oscillate
whatsoever.
I tried modern 2N3055s from different brands and some wouldn't
oscillate at
all, and others would oscillate so wildly that the regulator couldn't hold
it and the H.V. went all the way to the roof.

Add to this the uncertainty around any old or used 2N3055s because of
fakes
flooding the market and you have a difficult part to source or even to
assure the one you got inside the scope is up to the task.

If your Q1418 is not an original Tek part, or if it tests bad, avoid
yourself the trouble and get an original part (Qservice in Greece or
Sphere
in Canada are the 2 reputable sources that everybody in this group know
that comes to my mind).
If they don't have one with the Tek part-number in it, it will at least be
from the right "family" (Hometaxial) or yet, at least known to work on
your
scope.
I don't bear any relation to either of them sellers, besides their
reputation on this group.

There are already too much variables to the troubleshooting of this
circuit, to be unsure about the transistor, if it would or would not work.

I wish you luck.

Rgrds,

Fabio

2017-11-01 16:02 GMT-02:00 joseph@danyabutter.com [TekScopes] <
TekScopes@yahoogroups.com>:

pdxareaid,

Thanks for the offer and information. I think it might be a little much
for me right now but I do have some interest. This scope (Tek 465)

requires

a little understanding on the circuitry and quite possibly a little

luck to

troubleshoot. My interest in the simulation was to keep myself from
throwing parts at it (ex. capacitors, multiplier, other) and

understand the

circuit before messing with it. This scope has no diagnostics, a
rudimentary service manual, and appears to have a condition that may

not be

a typical issue for the scope. The regulator for the oscillator

appears to

have a very weak drive signal and the frequency is off (25 kHz

instead of

50 kHz) and I'm trying to figure out why. Most folks have the opposite
situation that drives the oscillator too hard and it blows the fuse

or the

multiplier has failed and it blows the fuse.

When the restorer diodes went bad on your Tek 465B, what was the failure
mode? No display at all/Partial display/unusable display/blowing
fuses/oscillator frequency not correct/other??????

Thanks again for the offer.

Joe


[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

I have my 30+ year old Weller 8200 soldering gun which I put a new
housing on about 5 years ago.

Then I have a pair of Weller WTCP style Magnastat soldering iron
stations. These are the ones which use the curie temperature of the
tip to regulate the tip temperature. One of mine is the military
version:

<http://www.stevenjohnson.com/soldering/stations.htm>
<http://www.stevenjohnson.com/soldering/pics/weller-mil-01.jpg>

I also have a big Weller W100P-3 100 watt temperature controlled iron
which runs directly on 120 volts AC. I used to have a W60P-3
temperature controlled iron which I intended as a portable replacement
for my soldering gun around the house but as was pointed out, the
soldering gun is safer because of its instant on capability and
actually more convenient. I lent the W60P-3 to a friend to work on a
job site who promptly plugged it into an outlet wired incorrectly to
240 volts AC which burned it out.

The advantage of using a temperature controlled soldering iron cannot
be overstated. With temperature control, the iron may be higher power
and have higher thermal capacity while operating at a lower
temperature. All of these attributes make for easier operation and
less damage to printed circuit boards and parts.

If you are looking for a new temperature controlled soldering iron,
then consider the price, availability, and variety of the tips. I
generally prefer shorter and fatter tips which deliver more heat at
lower temperatures.

Hello Joe,
I have a 464 which had problems with the HV circuitry when it got to me.
The H.V inverter of the 464 is VERY, VERY similar to yours (it's basically
the same circuit).
In the process of solving my primary problem (which was in the H.V.
transformer... not necessarily your case) I got my original tek part
151-0140-00, a "selected" 2N3055 burned.

What brought me to writing to you is only to emphasize FURTHER (others
already pointed it out) that the 2n3055 (Q1418) in this circuit is REALLY
critical.
When my original got burnt, from about 5 or 6 different 2n3055 I tried, the
circuit only worked with one of them, and still, I needed to change the
value of a resistor, to lower a little bit its base drive current.
The one that worked on my case was the MJ15015 (Which David Hess mentioned
earlier and which he added to his list because of my case).
I tried the 2n3772 and it oscillated at an harmonic of the transformer
characteristic frequency (I think 3rd or 5th harmonic, don't remember now).
Curiousby itslef because exactly the 2n3772 has a low Ft of 200KHz, the
lower of all.
I even thought it was a fake, but I opened it up later on and it was
clearly an original part (mine was from ST).
I tried to buy from a local auction site a vintage RCA 2n3055, dated
something around 1969 (markings where too faded away). I`m not sure it's a
Hometaxial part as the original tek part is, but this one didn't oscillate
whatsoever.
I tried modern 2N3055s from different brands and some wouldn't oscillate at
all, and others would oscillate so wildly that the regulator couldn't hold
it and the H.V. went all the way to the roof.

Add to this the uncertainty around any old or used 2N3055s because of fakes
flooding the market and you have a difficult part to source or even to
assure the one you got inside the scope is up to the task.

If your Q1418 is not an original Tek part, or if it tests bad, avoid
yourself the trouble and get an original part (Qservice in Greece or Sphere
in Canada are the 2 reputable sources that everybody in this group know
that comes to my mind).
If they don't have one with the Tek part-number in it, it will at least be
from the right "family" (Hometaxial) or yet, at least known to work on your
scope.
I don't bear any relation to either of them sellers, besides their
reputation on this group.

There are already too much variables to the troubleshooting of this
circuit, to be unsure about the transistor, if it would or would not work.

I wish you luck.

Rgrds,

Fabio





2017-11-01 16:02 GMT-02:00 joseph@danyabutter.com [TekScopes] <
TekScopes@yahoogroups.com>:

pdxareaid,

Thanks for the offer and information. I think it might be a little much
for me right now but I do have some interest. This scope (Tek 465) requires
a little understanding on the circuitry and quite possibly a little luck to
troubleshoot. My interest in the simulation was to keep myself from
throwing parts at it (ex. capacitors, multiplier, other) and understand the
circuit before messing with it. This scope has no diagnostics, a
rudimentary service manual, and appears to have a condition that may not be
a typical issue for the scope. The regulator for the oscillator appears to
have a very weak drive signal and the frequency is off (25 kHz instead of
50 kHz) and I'm trying to figure out why. Most folks have the opposite
situation that drives the oscillator too hard and it blows the fuse or the
multiplier has failed and it blows the fuse.

When the restorer diodes went bad on your Tek 465B, what was the failure
mode? No display at all/Partial display/unusable display/blowing
fuses/oscillator frequency not correct/other??????

Thanks again for the offer.

Joe


[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

RE-TX - SENT PERSONALLY BY MISTAKE


Hello,

if you have significant frustration tolerance, Arrow also ships for free from zero and does so worldwide.


But CAVE: you pay customs if outside of the USA

--
With best regards
Tam Hanna
---

NEW: Enjoy electronics? Like seeing oscilloscopes get repaired? Please subscribe to my new YouTube channel -> http://www.youtube.com/user/MrTamhan

On 11/01/2017 03:53 PM, Dan Rae danrae@verizon.net [TekScopes] wrote:

Seeing that Digikey will use USPS First Class for small orders of below
a certain weight (one today for me cost $3.39) and they invariably come
in two working days from Minnesota to Southern California, I see no
benefit in writing checks etc.,

Right. Like Shirley said.

But, if you have a bunch of designs in the works and you know you won't get to soldering it for two weeks,
it's a match. My other benefit is creating a list and checking it off as I do it,
and not having it hang around waiting to be complete enough for shipping and payment steps.
I get to send off 2 or 3 of these instead of one big one. Sometimes I get more parts than I'll use
because I changed my mind, changed my design by the time they arrived. Then they were dirt cheap
and I don't fret over it. Maybe I act like a hobbyist while designing for mass production, but I like it.

Hi, I am in Spain and order at eu.mouser.com on a regular basis. As soon as my order is over €50 (not USD) they drop the shipping fee to zero.


All the parts come from the US, but they ship intercompany first, so I never have problems with importtaxes.
Usually it takes 5-6 days to get here.


Proper ESD packaging, fast shipping, email updates, tracking, the works.


I'm happy with there services, no connection with them.


Un saludo,


Leo

Seeing that Digikey will use USPS First Class for small orders of below a certain weight (one today for me cost $3.39) and they invariably come in two working days from Minnesota to Southern California, I see no benefit in writing checks etc.,

Dan

On Wed, 1 Nov 2017 08:04:24 -0000, you wrote:

Some vacuum tubes use the same date code format, and some early IC that appeared in the 400
series scopes also used the same format.

I well remember the confusion with TTL made in 1974. So say you had printed information 7404 and
7428. Was it a hex inverter made in week 28 of 1974, or a quad 2-input NOR buffer made in week 4 of
1974? It was OK if one had eg SN in front of it because that nailed which one was the part number -
but if you made the mistake of buying a generic part, it was perplexing for sure.

Craig

I remember 1974 TTL parts being confusing as well. When I looked
through my stash, I even found one which was in the wrong place do to
this.

The upper left corner is Fairchild which could be figured out if you
knew their alternate part numbers.

The upper right corner is Signetics which are especially confusing.

The lower left corner is National Semiconductor who prevented
confusion between the date code and part number by adding confusion
between different decades.

<https://imgur.com/a/xqOiU>

Barry
When you pay on line typically by credit card,  Digikey is charged a
service fee of typically 1.75% to 3% by the credit card company. Ever
see gas stations that offer discounts for cash? Same principle.

Then there is the time value of money, depending on the clearing service
agreement there can be a not-insignificant delay in receipt of the
actual funds. Sometimes called the "float"

Dave


On 11/1/2017 4:18 PM, Barry n4buq@knology.net [TekScopes] wrote:

No, that is their usual service with speed -- this is done with a

paper check

only.

This is slow and they use it to fill in between other rushes.

Buyer writes paper check, PO delivers it in 2 days, Digikey opens it

at their

leisure,
Digikey pulls parts at their leisure, Digikey boxes and adds ship

label at

their leisure,
UPS or USPS delivers it back in 2-5 days. Total time can be 7-10 days.

What I see coming from them is UPS shipment of their smallest box

usually.

When I ordered a tiny amount of something hard to hurt in cut tape,

it came

in a padded envelope.

Such an odd exception. I would think it would be more expensive for
them to handle the check. As you say, they get to do things "at their
leisure", but it doesn't seem to me that would make up for this
exception to their standard methods.

Good to know about this.

Thanks,
Barry - N4BUQ

--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com

I think it's not so much that they actually save any money with the check
orders. It's a nod to their hobbyist-friendly roots. Digi-Key originally
came to be a success because they were one of the only ways that hobbyists
and garage startups could get parts. Most distributors would only sell to
people who established an account back then. Ubiquitous use of credit cards
changed that; nowadays only large companies bother to establish payment
accounts, small and medium sized ones use credit cards. Mouser was the
other main one; they also took checks. Allied was yet another important
source for a while, until their dalliance with Radio Shack messed things
up. Jameco started explicitly as a hobby-oriented company and gradually
expanded into corporate sales; they're useful for the more limited
selection of parts they stock.

Basically, Digi-Key made the service slow and inconvenient enough that just
about every business customer will choose the usual route of paying for
shipping instead, so they're only out the shipping costs on the relatively
small number of orders for hobbyists and makers that they receive.

They do let you put together the order on the internet and then mail the
check. (At one time that was not true; you had to fill out the order sheet
and mail it.) Makes total sense; having to read order sheets would be slow
and error prone. It lets you make sure that the parts you want are in
stock. And it makes sure that they receive the right amount of money,
because the cart tells you exactly how big a check you need to send.


On Wed, Nov 1, 2017 at 4:18 PM, Barry n4buq@knology.net [TekScopes] <
TekScopes@yahoogroups.com> wrote:

No, that is their usual service with speed -- this is done with a paper

check

only.

This is slow and they use it to fill in between other rushes.

Buyer writes paper check, PO delivers it in 2 days, Digikey opens it at

their

leisure,
Digikey pulls parts at their leisure, Digikey boxes and adds ship label

at

their leisure,
UPS or USPS delivers it back in 2-5 days. Total time can be 7-10 days.

What I see coming from them is UPS shipment of their smallest box

usually.

When I ordered a tiny amount of something hard to hurt in cut tape, it

came

in a padded envelope.

Such an odd exception. I would think it would be more expensive for them
to handle the check. As you say, they get to do things "at their leisure",
but it doesn't seem to me that would make up for this exception to their
standard methods.

Good to know about this.

Thanks,
Barry - N4BUQ

[Non-text portions of this message have been removed]

On 11/01/2017 03:18 PM, Barry n4buq@knology.net [TekScopes] wrote:

it doesn't seem to me that would make up for this exception to their standard methods.

Remember that they lose 3 to 4% on credit card transactions when doing a normal web order.
The checks ship free method doesn't have that cost.

It's not obvious how it works, but I guess they get many hobbyists business
started off buying without having to spend much phone time on them. After this start,
they will buy again when they are in a rush.

Perhaps they could make a web page that accepts scans of checks, but they WANT
primitive paper checks just to match their target hobbyist's behavior
and not give away too much to others who really are in a rush, but
like a deal. You could easily craft an order that costs them, but when I do mine,
it often has enough profit margin that it is just a break even, not a loss.

Maybe some purchasing departments still use checks, so they have the check reading machinery
for quickly depositing them. It's a mystery. Works though.

Thanks chaps, got my answer :-)

Yeah must have been confusing with those early/vanilla 7400 chips, given the period that they appeared on the market ! LOL I guess the confusion soon ended though, as soon as the first variants arrived : L, S, LS....

I pulled each and every one of the 30 or so tubes that my 317 scope comprises... not one of them had a readable date code ! On some of them I could see signs/traces proving that there USED to be a date code... but that was long ago I think ! LOL

These tubes have ivory and grey prints on them, which appear to stand the test of time decently well, for the most part. However they also feature red prints, which appear to be much less time proof ! :-/ Obviously, the date codes were invariably printed using that red stuff :-(

But... my savior came from the ONE single tube that was different from all the others. It's a big guy in a much larger package than all the others, a " 6080 " model, used for the cathode followers in the LV power supply. It features a metallic base/shroud, and the date code was printed on there rather than on the glass part. Lucky me. Says mid 1962, 35th week.

The cap cans indeed were of great help as well, being all engraved rather than printed. Date codes on them range from last week of 1951 up to 13rd week of 1962.

So my particular scope is about mid 62 then.

Thanks for the help.


Regards,


Vincent Trouilliez

No, that is their usual service with speed -- this is done with a paper check
only.

This is slow and they use it to fill in between other rushes.

Buyer writes paper check, PO delivers it in 2 days, Digikey opens it at their
leisure,
Digikey pulls parts at their leisure, Digikey boxes and adds ship label at
their leisure,
UPS or USPS delivers it back in 2-5 days. Total time can be 7-10 days.

What I see coming from them is UPS shipment of their smallest box usually.
When I ordered a tiny amount of something hard to hurt in cut tape, it came
in a padded envelope.

Such an odd exception. I would think it would be more expensive for them to handle the check. As you say, they get to do things "at their leisure", but it doesn't seem to me that would make up for this exception to their standard methods.

Good to know about this.

Thanks,
Barry - N4BUQ

On 11/01/2017 01:10 PM, Bert Haskins bhaskins@chartermi.net [TekScopes] wrote:

Do you know if this will work if you order online and pay with Paypal?

No, that is their usual service with speed -- this is done with a paper check only.

This is slow and they use it to fill in between other rushes.

Buyer writes paper check, PO delivers it in 2 days, Digikey opens it at their leisure,
Digikey pulls parts at their leisure, Digikey boxes and adds ship label at their leisure,
UPS or USPS delivers it back in 2-5 days. Total time can be 7-10 days.

What I see coming from them is UPS shipment of their smallest box usually.
When I ordered a tiny amount of something hard to hurt in cut tape, it came in a padded envelope.