Date   
Re: Odd screw heads in a Tek 497P

george edmonds
 

Hi All
There are multiple versions of Phillips type screws with different angles, The Japanese have their own version.
73 George G6HIG

On Saturday, May 18, 2019 11:28 AM, A Rhodes <@ARHODES> wrote:


Maybe they are Pozidrive?  They look like Phillips but are NOT.  The Pozi screw heads usually have a fine line impressed between each of the arms of the cross shaped receptacle in the screw head.

-Tony

Sent from my 1837 Babbage Analytical Engine

On May 17, 2019, at 8:33 PM, radioconnection@... wrote:

None of my Phillips head drivers seem to properly fit the screws holding the boards in my 497P.  It there a special tool that I need?

Peter


Re: Odd screw heads in a Tek 497P

Chuck Harris
 

Asian made screws with a dot between the slots are also
posidrive.

Pozidrive screws do not have a camming angle, but rather
have straight sided slots. That is why Phillips and Reed Prince
screw drivers ( the only camming slot systems I am aware of...)
won't work.

-Chuck Harris

george edmonds via Groups.Io wrote:

Hi All
There are multiple versions of Phillips type screws with different angles, The Japanese have their own version.
73 George G6HIG

On Saturday, May 18, 2019 11:28 AM, A Rhodes <@ARHODES> wrote:


Maybe they are Pozidrive? They look like Phillips but are NOT. The Pozi screw heads usually have a fine line impressed between each of the arms of the cross shaped receptacle in the screw head.

-Tony

Sent from my 1837 Babbage Analytical Engine

On May 17, 2019, at 8:33 PM, radioconnection@... wrote:

None of my Phillips head drivers seem to properly fit the screws holding the boards in my 497P. It there a special tool that I need?

Peter









Re: IMPORTANT: Photos are eating up our storage

Carsten Bormann
 

On May 18, 2019, at 09:04, Tom Gardner <tggzzz@...> wrote:

On 18/05/19 04:46, Carsten Bormann wrote:
On May 18, 2019, at 04:00, Chuck Harris <cfharris@...> wrote:
If you are going to delete the photos, then you might as well
delete the messages too.

The photos and the messages should exist for equal terms.
Makes sense to me, but remember that all messages and their attachments have been sent to hundreds of people who can dig them up if needed.
If they aren't stored on the server, how would

* new members access them?
They will ask on the list for who still has them. (You cannot argue for deleting/maiming stuff and then ask why it no longer is available in its full glory.)

But most likely, none of this will ever happen, because groups.io will update their limits before we hit them.

* people search for information? Neither email program's searches nor most
forums searches are anywhere near as good as google.
The messages that refer to them are still there and are googleable.

Besides, there’s no way I want to store 4GB of email messages on my machine!
Then don’t: that’s what gmail with imap access is great for.

Grüße, Carsten

Re: IMPORTANT: Photos are eating up our storage

Tom Gardner
 

On 18/05/19 13:20, Carsten Bormann wrote:
On May 18, 2019, at 09:04, Tom Gardner <tggzzz@...> wrote:
On 18/05/19 04:46, Carsten Bormann wrote:
On May 18, 2019, at 04:00, Chuck Harris <cfharris@...> wrote:
If you are going to delete the photos, then you might as well
delete the messages too.

The photos and the messages should exist for equal terms.
Makes sense to me, but remember that all messages and their attachments have been sent to hundreds of people who can dig them up if needed.
If they aren't stored on the server, how would

* new members access them?
They will ask on the list for who still has them. (You cannot argue for deleting/maiming stuff and then ask why it no longer is available in its full glory.)
That would be:

* really annoying for most people; too many messages
* unlikely to succeed; most people couldn't be bothered to take time to find
if they might have stored them


But most likely, none of this will ever happen, because groups.io will update their limits before we hit them.
That's a /commercial/ decision, not a technical one. Many companies offer cheap services to tempt people to start using the service, then hit them with large charges after they are hooked.

It would be imprudent to rely on a limit increase.


* people search for information? Neither email program's searches nor most
forums searches are anywhere near as good as google.
The messages that refer to them are still there and are googleable.
If that is sufficient, then the photos are unnecessary in the first place


Besides, there’s no way I want to store 4GB of email messages on my machine!
Then don’t: that’s what gmail with imap access is great for.
Same point w.r.t. google inbox and folders.

Besides, I use IMAP to mirror the google folders on my own machine, so the messages will always be accessible to me.

Re: IMPORTANT: Photos are eating up our storage

Carsten Bormann
 

On May 18, 2019, at 09:34, EJP <esmond.pitt@...> wrote:

(1) switch on attachments
Now this doesn't work for people who use the Web interface to post. There is no attachment facility.
Interesting. So the Web posters would still need to use photos/files (which may be more natural for them, anyway). Everyone else would benefit.

Grüße, Carsten

151-5001-00 cross reference?

radioconnection@...
 

SOT-23 NPN silicon devices used on the 497P A69A4 board. 15 MHz crystal oscillator and a buffer driver for a 74S74 TTL divider chip. Searched for a cross reference and no luck. Any suggestions?

Peter

Re: 151-5001-00 cross reference?

radioconnection@...
 

Never mind... found it the HARD way by going through other manuals. Found the cross in the PAL SPG-271 sync generator manual.

151–5001–00 119–2501–03 119–2501–03 TRANSISTOR,SIG:BIPOLAR,NPN;40V,200MA,300MHZ,AMPL 04713 MMBT3904LT1

No OEM listed in the 487P book.

Common 3904 variant?

Pete

Re: Tektronix equipment from nuclear industry, any reason to be afraid?

Ke-Fong Lin
 

Hi again guys,

So I took the opportunity to buy a geiger counter, a made in germany "gamma scout".
It's not cheap (375 euros sales tax included) but hopefully I'm no longer a broke student.
It is capable of alpha, beta, and gamma detection, whereas most counters are beta & gamma only.

I've checked my tektronix gear, in particular the ones from PSE&G Nuclear Department and the french CEA nuclear research.
Of course, the readings are perfectly fine, and shows only background radiation (0.12-0.14 uSv/h going as low as 0.1 uSv/h in basement).

A lot of messages mentioned nuclear bomb testings but my worries were rather the general daily "routine" of test equipment use in a nuclear industry.
In particular, following the safety rules properly to avoid contamination during disposal of used equipment. Whereas in nuclear bomb testing, my guess is that everybody's very careful and focused.
And that applies to any industry in general, being chemicals or biological.

That was also a good opportunity for me to at last purchase a geiger counter.
Living in France and having experienced the aftermath of the Tchernobyl accident, I've always wanted to have one.
That especially as the french government at that time minimized (to say the least), what the fallout values were.


Best regards,

Re: Odd screw heads in a Tek 497P

Carsten Bormann
 

On May 18, 2019, at 14:10, Chuck Harris <cfharris@...> wrote:

Asian made screws with a dot between the slots are also
posidrive.
Not really:
https://en.wikipedia.org/wiki/List_of_screw_drives#JIS_B_1012

A Pozidriv can easily be recognized by the cross pattern on the head that is 45 degrees off the cross-slots where you insert the driver:
https://en.wikipedia.org/wiki/List_of_screw_drives#Pozidriv

Given the amount of misinformation one can find on the Web (and from mechanics, even battle-proven ones) regarding screw drive systems, Wikipedia really is your friend here.

Grüße, Carsten

Re: Odd screw heads in a Tek 497P

Chuck Harris
 

And yet, it too is a cross shaped, with square sides that won't
cam out. and is incompatible with Phillips... Just like the pozidriv.

Those I have tried fit the pozidriv screwdrivers just fine.


-Chuck Harris

Carsten Bormann wrote:

On May 18, 2019, at 14:10, Chuck Harris <cfharris@...> wrote:

Asian made screws with a dot between the slots are also
posidrive.
Not really:
https://en.wikipedia.org/wiki/List_of_screw_drives#JIS_B_1012

A Pozidriv can easily be recognized by the cross pattern on the head that is 45 degrees off the cross-slots where you insert the driver:
https://en.wikipedia.org/wiki/List_of_screw_drives#Pozidriv

Given the amount of misinformation one can find on the Web (and from mechanics, even battle-proven ones) regarding screw drive systems, Wikipedia really is your friend here.

Grüße, Carsten




Re: 151-5001-00 cross reference?

Michael A. Terrell
 

Yes, the MMBT3904 is a generic, surface mount version of the 2N3904.. It is
a jellybean component.that is available at just about any distributor, or
from scrap boards. They are marked 1A.
On Semiconductor is the OEM we used for this, but Fairchild and dozens of
other OEM make them.

On Sat, May 18, 2019 at 10:08 AM <radioconnection@...> wrote:

Never mind... found it the HARD way by going through other manuals. Found
the cross in the PAL SPG-271 sync generator manual.

151–5001–00 119–2501–03 119–2501–03
TRANSISTOR,SIG:BIPOLAR,NPN;40V,200MA,300MHZ,AMPL 04713 MMBT3904LT1

No OEM listed in the 487P book.

Common 3904 variant?

Pete



Re: 151-5001-00 cross reference?

Albert Otten
 

Hi Pete,

You might also have consulted Tek_RPR_151-Transistors.pdf (Tekwiki) to find the mfg.
An ON datasheet lists all 3904 packages (TO-92,SOT-23, SOT-223) without any distinction in the electrical specs.

Albert

On Sat, May 18, 2019 at 04:08 PM, <radioconnection@...> wrote:


Never mind... found it the HARD way by going through other manuals. Found the
cross in the PAL SPG-271 sync generator manual.

151–5001–00 119–2501–03 119–2501–03
TRANSISTOR,SIG:BIPOLAR,NPN;40V,200MA,300MHZ,AMPL 04713 MMBT3904LT1

No OEM listed in the 487P book.

Common 3904 variant?

Pete

Re: Odd screw heads in a Tek 497P

Larry McDavid
 

If you often work on electronic, optical or camera equipment made around the world, you will want three types of cross-head drivers:

Phillips (unfortunately the US standard and a really poor choice)

Pozidriv (used throughout the rest of the world instead of Phillips)

JIS (commonly seen on Japanese electronics and cameras). Pozidriv drivers do not fit these well! Get the correct driver for the screw you use...

I often work on microscopes that have truly tiny screws that are often JIS.

These three types can be easily purchased on Amazon. Wiha makes excellent Phillips and Pozidriv drivers but, alas, not JIS.

I have a friend in The Netherlands and he had to ask me to buy and ship some Phillips drivers to him because he could not buy them there. All the cross-head screws sold there are Pozidriv.

Square drive or Robertson heads are now found in some high-torque wood screws in the US.

Pozidriv heads are found in some wood deck screws; boxes of those screws often include a Pozidriv bit. These bits are usually marked PZ.

There are some interesting combination heads found in electrical equipment. Some combine Pozidriv with flat blade recesses and circuit breaker screws combine flat blade and square drive recesses.

The Wiki article referenced below is a really good one.

Larry


On 5/18/2019 11:27 AM, Chuck Harris wrote:
And yet, it too is a cross shaped, with square sides that won't
cam out. and is incompatible with Phillips... Just like the pozidriv.
Those I have tried fit the pozidriv screwdrivers just fine.
-Chuck Harris
Carsten Bormann wrote:
On May 18, 2019, at 14:10, Chuck Harris <cfharris@...> wrote:

Asian made screws with a dot between the slots are also
posidrive.
Not really:
https://en.wikipedia.org/wiki/List_of_screw_drives#JIS_B_1012
...
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

Re: 151-5001-00 cross reference?

Jim Ford
 

BTW, On Semiconductor bought Fairchild Semi, so they're one company now.  I can barely keep up with the consolidation in the semiconductor industry these days. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: "Michael A. Terrell" <@michaelaterrell> Date: 5/18/19 12:11 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] 151-5001-00 cross reference? Yes, the MMBT3904 is a generic, surface mount version of the 2N3904.. It isa jellybean component.that is available at just about any distributor, orfrom scrap boards. They are marked 1A.On Semiconductor is the OEM we used for this, but Fairchild and dozens ofother OEM make them.On Sat, May 18, 2019 at 10:08 AM <radioconnection@...> wrote:> Never mind... found it the HARD way by going through other manuals. Found> the cross in the PAL SPG-271 sync generator manual.>> 151–5001–00 119–2501–03 119–2501–03> TRANSISTOR,SIG:BIPOLAR,NPN;40V,200MA,300MHZ,AMPL 04713 MMBT3904LT1>> No OEM listed in the 487P book.>> Common 3904 variant?>> Pete>> >>

1A2 plugin for sale

Bob Albert
 

Very clean; some sticker residue. Was working before storage; to the best of my knowledge nobody has worked on this unit. Cal sticker 1980. Utilizes two 7586 Nuvistors and one 6DJ8 tube plus a number of transistors. Serial 001795.

This is a fast dual trace unit. Entertaining offers before going on ebay. Shipping shouldn't be too expensive. I live in Los Angeles.

Re: 1A2 plugin for sale

Roy Morgan
 

How is it different from the 1A1??

Roy sends.

On May 18, 2019, at 3:51 PM, Bob Albert via Groups.Io <bob91343=yahoo.com@groups.io> wrote:

Very clean; some sticker residue. Was working before storage;

Re: 1A2 plugin for sale

Dave Wise
 

1A2 is a straight-across CA replacement while 1A1 is a step up.

They're both 50MHz.
1A2 maximum sensitivity is 50mV/div where the 1A1 goes down to 5mV, or 500uV if you cascade the channels.
1A1 can slave Channel 1 to Timebase A and Channel 2 to Timebase B in a 547 mainframe (dual beam emulation) while 1A2 cannot.
On the other hand 1A2 can select which channel to route to the 544/546/547 plugin trigger line while 1A1 follows vertical mode.

The hobbyist who has enough 1A1's will be interested in the 1A2 only if he is also a collector of the complete-ist persuasion.
If you don't have a 1A1, a 1A2 will keep you going while you wait. I have one of each and use both.

HTH,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Roy Morgan <k1lky68@...>
Sent: Saturday, May 18, 2019 1:18 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 1A2 plugin for sale

How is it different from the 1A1??

Roy sends.

On May 18, 2019, at 3:51 PM, Bob Albert via Groups.Io <bob91343=yahoo.com@groups.io> wrote:

Very clean; some sticker residue. Was working before storage;

Re: Tek 2465A S/N B019121

Lawrence Joy
 

Okay guys, thanks for all your comments and notes. Here is my work so far and a question:
1) I made my own parts list (PL) of the capacitors on the Regulator (A2A1) ASSY and the Invertor (A3) ASSY using an electronic spreadsheet. This is so I can do a sort on the Tek P/N or description to see how many capacitors of each value and type I would need to look at for replacing. The capacitor count for the A2A1 ASSY is 25 and for the A3 ASSY it is 33, for a total of 58 capacitors. Not all of these would need replacing.
2) I looked up that United Chemicon EKZN500ELL331MK16S electrolytic capacitor on Mouser, Digi-Key, and Arrow. Looks like that is a very popular item. Mouser doesn't have any, they say factory 19 week lead time with 1800 pcs on order to ship 2019-07-26. Digi-Key doesn't have any, they say 16 week lead time and a ship date of 2019-08-12. Arrow says a lead time of 18 weeks, no idea if they have any on order, MOQ of 2000 pcs. Summer is going to be over with by the time I would be able to get any. I will have to look at Panasonic and Nichicon for comparable capacitors.
3) Are the X safety capacitors A2A1C1018, in series with A2A1R1018, and A2A1C1016, in series with A2A1R1016? When replacing with modern day plastic safety capacitors do you remove the series resistors (replacing with a short piece of wire, of course)?
4) How do you remove Torx head screws that seem deformed? There is a black plastic cover over the A3 and A2A1 assemblies at the rear of the chassis. This cover is held to the rear chassis with two Torx head screws of what seem to be T-10 size. I was able to remove one of the screws, the one by the fan, but the other screw by the CRT back end cover was a bear. My Torx T-10 size driver was too small and my Torx T-15 size driver was way too big. It seemed like I needed the next size up, a T-11. But I found out there is no T-11, T-12, T-13, or T-14, the size jumps from T-10 to T-15. The only thing I can figure is the female Torx lobes are not formed correctly. So I used a Dremel® tool with a cutoff wheel and was able to remove enough of the top of the screw to pop it loose. Then I was able to remove only two of the three screws that hold the metal heatsink bar, that holds the six TO-220 packaged voltage regulators and pass transistors to the bottom of the chassis, which are part of the A2A1 CCA. The screw head is between two of the TO-220 packages and not out in the clear. And even if the screw head was in the clear I wouldn't want to have small metal pieces flying around the circuitry. How to remove?
--Larry

Re: [OT] surface mount components

Alberto I2PHD
 

When working with SMDs, I find this tool very handy :




Made by Mastech, model Nr. MS8911.

When grabbing an SMD component, it can tell you whether it is a resistor, a capacitor or an inductor, showing also its value.
The measure can be performed at 4 different frequencies, and it can even tell the ESR...
Given that the smaller SMD components do not have on their bodies enough space to print their value, it is in these cases a cannot-do-without tool.

Paid about 50 Euro one year ago.

--
/*73 Alberto I2PHD*
Keyboard Not Found : Press F1 to continue/

Re: [OT] surface mount components

Alberto I2PHD
 

On 2019-05-19 0:56, Alberto I2PHD wrote:
When working with SMDs, I find this tool very handy :




Made by Mastech, model Nr. MS8911.
Hmmm, it looks like the photo did not get through...

It can be seen here :

http://i2phd.org/public/Twezeer.jpg

--
/*73 Alberto I2PHD*
Keyboard Not Found : Press F1 to continue/