Date   

Re: TM500/TM5000 extender v0.8

KeepIt SimpleStupid
 

Wire typically comes in 2 strandings, one being more flexible than the other.
Silicone insulated wire is a possibility.  The jacket is bit more flexible.
Heat shrinking the edge connector wires is a possibility too, but the ability to probe safely sounds even better.


Re: Tek 222/224 Battery Replacement

garp66
 

hi Jeff,

Any chance you can include some *jumpers* so that this battery replacement PCB unit can also function in an AC/DC Tek 422 scope ?
(With or without a 3D printed plastic retrofit case ?)

thank you,
rick


Re: New 2465 Seimens brushless motor

Chuck Harris
 

One hates to be a forgone conclusion...

Perhaps using killed HCl, also known as
zinc chloride. killed HCl is what you get
when you dissolve as much zinc into HCl as
you can. It eliminates that nasty evaporation
problem that HCl has.

Zinc Chloride is the active ingredient in the
old soldering flux tins from the days of steel
chassis TV's. It was a mixture of Zinc Chloride
and petroleum jelly, with something to keep them
from separating out.

-Chuck Harris

victor.silva via Groups.Io wrote:

The seller has little experience with ebay and has no idea on how to setup multiple items shipping.
I was the one that bought 20 (at a discount) and initially the shipping was $320 for parcel post!

It took forever for him to revise the invoice with continuous hand holding all the way.

One note on these motors, not just from this seller, but I've seen this issue on all the NOS Seimens motors I've used;
The terminals do not solder well. I've tried fluxing, long heating, etc., the terminals just don't wet well.

The only solution I have found was to dip the terminal for 10 secs in 10% HCl. Then neutralize with baking soda solution and dry well.
After this the solder would wet very well.
I know Chuck Harris will caution against this, but I believe his concerns are that once you apply HCl to the motors, if any vapors or liquid
creep inside the motor it will be toast.
I would love to hear of any suggestions or if anyone has success soldering these without using HCl to clean the terminals.

Thanks,
--Victor




Re: One more quick question about CRTs

greenboxmaven
 

There are several reasons to delay the B+, they are mostly to protect high current tubes that are not yet at full emission from damage. The cathode current of a one gun CRT is usually a hundred microamps or so, unlikely to damage the cathode. Consider solid state TV receivers that applied full operating voltage to the pix tube the moment the set was turned on, and an image faded in over about a 15-20 second warmup, usually needing a minute or two to reach fullest brightness and resolution. Delaying the B+ in the scope will protect the voltage regulator circuits, prevent excessive voltage on the ciruitry because of there being no load, and avoiding wild voltage excursions, parasitic oscillations, and instability in directly coupled or multiple paralell tube amplifier circuits.

Bruce Gentry, KA2IVY

On 3/27/20 10:20 AM, Ernesto wrote:
Hi,
Since I realize the vast expertise in the group, I want to ask a question for which I didn't find an answer.
It is about the life of the metal oxide cathode in a CRT.
In vacuum tubes, insufficient electron emission due to insufficient heat can shorten the life of the cathode, the tube.
This is why my 547 scope has a time delay before the higher voltages turn on.
Is the CRT included in this precaution, or is it only for the regular tubes?

Regards,
Ernesto



Re: TM500/TM5000 extender v0.8

Oz-in-DFW
 

First, really excellent work.

I also have some suggestions and comments that are work exactly what you paying for them ;-)

Ribbon cable will be more convenient, but I'm not sure it's better or worse. the advantages I see are:
- neater and less likely to be tangled.
- easy to change when the wires work harden and break
- will likely connect all contacts - those contacts were doubled for a reason - usually lower connection resistance for power, but also reduced inductance,, etc.

Disadvantages:
- Much higher wire to wire capacitance, including to ground wires
- generally stiffer
- smaller gauge wire

You can reduce a lot of the disadvantages of ribbon cable by separating the wires once the IDC connectors are installed. If you stick with discrete wires I'd use connectors on both sides to make replacement easier and less likely (due to better wire strain and bend relief when compared to soldering.

Whether you go with ribbon or not, I strongly suggest a second PCB on the unit-under-test side. Right angle PCB mount connectors are still available from distribution and are a whole lot easier to solder that individual wires. I also suggest test points or posts on that side as well. I have a TM503 on the bench and I hate pulling the covers to poke at a plug in. This lets you get the unit out of the case, but not easily probe backplane signals.

I second the suggestion to round the corners of the board, or at least break the point with a 45 degree cut.

As to split pads, I have library parts that are normally open and normally closed (10mil shorting trace between the pads) I use them a lot.


Re: New 2465 Seimens brushless motor

Mlynch001
 

Paul,

Don't get me started on taxes. The government now gets their pound of flesh, regardless. All of this stems from the brick and mortar retailers lobbying for taxing online purchases and the ever growing LUST for $$$ of the typical government. Politicians win, both ways, more tax $$$ to spend and lots of money coming (under the table) from the aforementioned lobbyists

--
Michael Lynch
Dardanelle, AR


Re: New 2465 Seimens brushless motor

Paul Amaranth
 

Yes, AND you get taxed on shipping as well.

Still, the total price is not terrible so I grabbed a spare as well.

PaulA

On Fri, Mar 27, 2020 at 08:18:47AM -0700, Mlynch001 wrote:
On Fri, Mar 27, 2020 at 09:41 AM, <joeschm@...> wrote:


As has been mentioned, shipping is somewhat high.
Becoming the "norm" on E-bay, outrageous shipping charges on many items. This seller actually has his item priced cheap, for a new motor, and even with the shipping, it is a good price. At least I thought so, since I bought one to keep as a spare.

--
Michael Lynch
Dardanelle, AR
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows


Re: New 2465 Seimens brushless motor

victor.silva
 

The seller has little experience with ebay and has no idea on how to setup multiple items shipping.
I was the one that bought 20 (at a discount) and initially the shipping was $320 for parcel post!

It took forever for him to revise the invoice with continuous hand holding all the way.

One note on these motors, not just from this seller, but I've seen this issue on all the NOS Seimens motors I've used;
The terminals do not solder well. I've tried fluxing, long heating, etc., the terminals just don't wet well.

The only solution I have found was to dip the terminal for 10 secs in 10% HCl. Then neutralize with baking soda solution and dry well.
After this the solder would wet very well.
I know Chuck Harris will caution against this, but I believe his concerns are that once you apply HCl to the motors, if any vapors or liquid
creep inside the motor it will be toast.
I would love to hear of any suggestions or if anyone has success soldering these without using HCl to clean the terminals.

Thanks,
--Victor


Re: New 2465 Seimens brushless motor

Mlynch001
 

On Fri, Mar 27, 2020 at 09:41 AM, <joeschm@...> wrote:


As has been mentioned, shipping is somewhat high.
Becoming the "norm" on E-bay, outrageous shipping charges on many items. This seller actually has his item priced cheap, for a new motor, and even with the shipping, it is a good price. At least I thought so, since I bought one to keep as a spare.

--
Michael Lynch
Dardanelle, AR


Re: New 2465 Seimens brushless motor

joeschm@...
 

This same motor is used in the Tek 7904A. I purchased a couple a few weeks ago. One is installed and working great.

As has been mentioned, shipping is somewhat high.


One more quick question about CRTs

 

Hi,
Since I realize the vast expertise in the group, I want to ask a question for which I didn't find an answer.
It is about the life of the metal oxide cathode in a CRT.
In vacuum tubes, insufficient electron emission due to insufficient heat can shorten the life of the cathode, the tube.
This is why my 547 scope has a time delay before the higher voltages turn on.
Is the CRT included in this precaution, or is it only for the regular tubes?

Regards,
Ernesto


Re: Any Tektronix magnetic shield for a CRT? A strange problem...

 

I rectify my previous post. The floating HV supplies are for the GRIDS of the CRTs, not their filaments. (sorry, I'm not thinking fast enough.

Is there some way to edit the submitted posts?

Ernesto


Re: Any Tektronix magnetic shield for a CRT? A strange problem...

 

Hi Bruce,

What you said of the beam being moved off the aperture of the gun rather than deflected to the side for blanking makes more sense.
This clever system makes a lot of sense, and makes me wonder why it is not used in all CRTs.
The 422 scope uses a CRT with this method, and it operates at close to ground potential, therefore saving the need for a separate HV floating supply for the filament. That blanking signal there is about 30 volt.

Ernesto


Re: Any Tektronix magnetic shield for a CRT? A strange problem...

Carsten Bormann
 

On 2020-03-27, at 04:27, Ed Breya via Groups.Io <edbreya=yahoo.com@groups.io> wrote:

If you suspect some high degree of localized magnetization "hot spots," just sprinkle some fine iron filings or magnetic laser toner around on it, and look for the patterns.
Or, if you don’t want to clean up after that:
https://www.ebay.com/sch/i.html?_nkw=magnetic+field+viewing+film

Grüße, Carsten


Re: need a tunnel diode

Glenn Little
 

That is Deane Kidd's stock. Being sold by his family. Deane was very helpful in helping maintain Tektronix equipment.

Glenn
WB4UIV

On 3/27/2020 7:32 AM, GerryR wrote:
Aldue,
I bought some of these:
https://www.ebay.com/itm/Set-10-Tektronix-152-0125-01-4-7mA-TUNNEL-DIODES-replaces-1N3717-TD-3A-Tested/313002120835?hash=item48e0615683:g:ft4AAOSwsdJdoQL0

They are 152-0125-01 instead of -00; I don't know the difference, but he still has some for sale.

GerryR
KK4GER


----- Original Message -----
From: "aldue" <@aldue>
To: <TekScopes@groups.io>
Sent: Thursday, March 26, 2020 10:44 PM
Subject: [TekScopes] need a tunnel diode


Hi Tek fans. Me too. I am semi-bleeding for a tunnel diode. Please suggest substitutes or sources. Tek 152-0125-00, 4.7mA 15-18pF THANK you, aldue



--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: Any Tektronix magnetic shield for a CRT? A strange problem...

Chuck Harris
 

I would bet that the magnet you found fell off of
the CRT, and was one of those used to steer the
beam through some minor element misalignment.

Tek typically stuck them to the neck of the CRT
with some scotch tape. The tape shrinks over time,
and the magnet sometimes "squirts" out of the side
of the tape.

-Chuck Harris

Ed Breya via Groups.Io wrote:

Before going through all sorts of grief with mu metal, you may want to take it all apart and carefully inspect the CRT and shield - you may find an actual magnet stuck inside somewhere. This happened to me once, working on an old scope long ago. I found a small permanent magnet that must have gotten dropped inside the scope guts, and it found its way to the nice mu shield right at the back edge by the CRT gun. At first I thought it was a mounting screw head, then realized it was a magnet hanging there.

If you look at "real" mu shields for CRTs and other devices, you'll find they are typically fully closed, magnetically, where the joints are overlapped quite a bit, or riveted, crimped, or spot welded. If your home-made one is just rolled but without the edges tightly bonded, there's a natural air gap that concentrates flux. Also, it may not even be mu metal, but just mild steel. Mu will tend to look like stainless steel, and be very soft, and rust-free. It is easily solderable. It should not retain magnetization very well, which is why it's good for shielding. The shielding effectiveness does degrade from deformation, but doesn't go to zero. I wouldn't worry too much about minor dents and dings.

If you suspect some high degree of localized magnetization "hot spots," just sprinkle some fine iron filings or magnetic laser toner around on it, and look for the patterns.

Ed




Re: TM500/TM5000 extender v0.8

A Rhodes
 

On Fri, Mar 27, 2020 at 06:27 AM, KeepIt SimpleStupid wrote:


Create a split pad.  I can't find a picture of one.  Basically, it's a pad
made from two trace segments that look like.(XXX|-|XXX).  Normally, the
center is open and bridged by solder by the end user.
In some layout programs, their library may have such a thing. It may be called a “solder jumper “

-Tony


Re: Tek 222/224 Battery Replacement

satbeginner
 

Hello,

I'm interested as well, however I am in Spain, so shipping might be an issue.

Thanks for sharing,

Leo


Re: Tek 222/224 Battery Replacement

SuddenLink
 

I am very interested as well. Thank you for sharing with the group.

Bob Ripley
Museum of Radio and Technology
Huntington, WV


Re: Any Tektronix magnetic shield for a CRT? A strange problem...

greenboxmaven
 

The first time I saw the unblanking method on a 212 portable it was quite interesting. The blanking plates are in the gun, well before the main deflection plates. It takes a lower voltage to move the beam off the aperature after the blanking plates than it would to do it with the main ones. Also, sending the beam into the side of the tube would give a faint glow from the secondary electrons dislodged by it, as well as causing pre-trace and retrace lines.

Bruce Gentry, KA2IVY

On 3/26/20 11:59 PM, Ernesto wrote:
Hi Dennis,

The 154-0667-00 CRT in the 1502 TDR which you suggested is indeed a nice tube, quite interesting. Thank you for the suggestion.
Something unusual I find for a Tektronix CRT is that its cathode is a direct heated filament. And the blanking of the trace is not done through the grid or cathode but by a pair of dedicated electrodes that I guess deflect the beam out of the area of the screen. It does not have post-acceleration, and the HV supply in the 1502 has a rare simplicity. I like it for the square screen and the internal graticule. But in the scope I have the square mumetal shield would run out of space, plus to interface it would require multiple modifications. So for the time being I may stay with what I have, and leave for later my dream of building a scope around the tube the 547 has, This when the time of the day increases from 24 to 48 hours (yes, retired people also run out of time)

The video form the company Mumetal you quoted is very interesting. Could sleeping inside a mumetal shield that eliminates the earth's magnetic field have homeopathic benefits?

Ernesto