Date   

Re: TM500/TM5000 extender project

John Griessen
 

On Feb 12, 2020, at 17:20, Ke-Fong Lin wrote:
For a pure extender use, there is just some wiring to be done. Otherwise, I'll have to provide some sort of BOM.
Please tell us more about how laborious that wiring is in various ways you have made it possible.
How do you see using the 7 through hole connectors? Are there 7 mating connectors you plan to supply
to users who might have difficulty getting just one of them?


Barrie Gilbert: The most prolific Analog IC designer ever

 

https://www.microwavejournal.com/articles/33425-living-and-learning-with-bar
rie-gilbert



More insights from my friend Barrie.



Dennis Tillman W7pF


Re: TM500/TM5000 extender project

Dave Daniel
 

I noticed that you don’t have anything to strain-relieve the wires. I’d add some holes through which cable ties could be run to capture the wires.

DaveD

On Feb 12, 2020, at 17:20, Ke-Fong Lin <anotherlin@...> wrote:

Hi everyone,

The PCB is ready! I've updated the preview and the schematics.

https://drive.google.com/file/d/14WSoPeQoIwup4532_YnxUz44PVxAYJ8T/view
https://drive.google.com/file/d/1E7RxXXPg_3-Kwd652mFbe5g-4zoBeAN_/view

In particular, I've added a small circuitry to generate the "power good signal" for the TM5000 modules.
It's basically a voltage divider from 8V to 5V, and an NPN buffer. The PWR specifies a full load (16mA) of TTL high (+5V).
A small drawback is that it always draws around 2-3mA even if not to needed (inserted in a mainframe).

Can some of you do a review of the schematic? Or give some comments or suggestions?
For those really curious, I can send the complete kicad project, just ask. Final version will be an github of course.
For a pure extender use, there is just some wiring to be done. Otherwise, I'll have to provide some sort of BOM.
I also have to write a small "documentation".

Plan is to send the PCB to fabrication (JLPCB) this week-end, after feedbacks.

Best regards,



Re: Push-push switch repair (need some theory of operation)

Ke-Fong Lin
 

Only remaining issue with the 7CT1N is that with PNP selected the dot is at
bottom right, not top right. Am I right in thinking this is controlled by
S70D, which is the part nearest the latch?
Yes, most probably.
On the 5CT1N, that part is much simpler: It's either +30 and -30 for each poles, or GND for both.
On the 7CT1N, one of the pole is connected to a voltage divider, which is itself connected to S230.
You may want to check the vert/horiz switch (S230).
My 5CT1N issues were only mechanical, with the 2 switches I've replaced the problems were gone.


Re: TM500/TM5000 extender project

Abc Xyz
 

Nice Board!

On Wed, Feb 12, 2020, 2:20 PM Ke-Fong Lin <anotherlin@...> wrote:

Hi everyone,

The PCB is ready! I've updated the preview and the schematics.

https://drive.google.com/file/d/14WSoPeQoIwup4532_YnxUz44PVxAYJ8T/view
https://drive.google.com/file/d/1E7RxXXPg_3-Kwd652mFbe5g-4zoBeAN_/view

In particular, I've added a small circuitry to generate the "power good
signal" for the TM5000 modules.
It's basically a voltage divider from 8V to 5V, and an NPN buffer. The PWR
specifies a full load (16mA) of TTL high (+5V).
A small drawback is that it always draws around 2-3mA even if not to
needed (inserted in a mainframe).

Can some of you do a review of the schematic? Or give some comments or
suggestions?
For those really curious, I can send the complete kicad project, just ask.
Final version will be an github of course.
For a pure extender use, there is just some wiring to be done. Otherwise,
I'll have to provide some sort of BOM.
I also have to write a small "documentation".

Plan is to send the PCB to fabrication (JLPCB) this week-end, after
feedbacks.

Best regards,




Re: TM500/TM5000 extender project

Ke-Fong Lin
 

Hi everyone,

The PCB is ready! I've updated the preview and the schematics.

https://drive.google.com/file/d/14WSoPeQoIwup4532_YnxUz44PVxAYJ8T/view
https://drive.google.com/file/d/1E7RxXXPg_3-Kwd652mFbe5g-4zoBeAN_/view

In particular, I've added a small circuitry to generate the "power good signal" for the TM5000 modules.
It's basically a voltage divider from 8V to 5V, and an NPN buffer. The PWR specifies a full load (16mA) of TTL high (+5V).
A small drawback is that it always draws around 2-3mA even if not to needed (inserted in a mainframe).

Can some of you do a review of the schematic? Or give some comments or suggestions?
For those really curious, I can send the complete kicad project, just ask. Final version will be an github of course.
For a pure extender use, there is just some wiring to be done. Otherwise, I'll have to provide some sort of BOM.
I also have to write a small "documentation".

Plan is to send the PCB to fabrication (JLPCB) this week-end, after feedbacks.

Best regards,


Re: WTF: TDS3000 Blank option modules.

Magic_Smoke
 

A very good tip. I'll see if I can get my hands on one somewhere, I've found it a little tricky to get things just right based on drawings alone.


Re: 11301/11302 in the Bay area

Jerry
 

The manual looks interesting but no real troubleshooting in it. I did see an adjustment for horizontal dynamic jitter or positioning, I can't find it again. The issue with my scope, other than dropping the constants, is that I can adjust the scope display pots to get a nice text display but there is something stored incorrectly because when I reboot, it is all out of focus again. But even when I get a nice text display, the trace doesn't overlay correctly. so the trace looks wide horizontally. I have the software for calibration and went through some of those but it looked, if I remember from last year or so, that it wasn't saving or holding the settings so it probably needs new flash ram.

I wanted a 400Mhz+ analog scope because all my DSOs do a poor job at displaying modulation no matter how much I screw around with them. The other thing I wanted an analog scope for was doing semiconductor curves. I have a couple of circuits (not the octopus type) that do a pretty good job of displaying curves. My DSOs, with the exception of my TDS3054D just don't work well there. I have all the plug-ins and use them in my DSA602 so I would love to get this one working, but I really think it is toast and I am going to take one more look and then trash it.

Thanks

Jerry


Re: 11301/11302 in the Bay area

Siggi
 

On Wed, Feb 12, 2020 at 10:21 AM Oz-in-DFW <lists@...> wrote:

Where did you find it? I have a sick one needing attention.




Re: 11301/11302 in the Bay area

Oz-in-DFW
 

Where did you find it? I have a sick one needing attention.


Re: WTF: TDS3000 Blank option modules.

Oz-in-DFW
 

All I'm suggesting is that you make the model to accommodate and correctly position the SIM connector.


Re: Any known issues with the 577?

 

Hi Eric,
A while back I posted my experience trying to follow the procedure in the manual to adjust the storage voltages. I found it very confusing to follow and the 4 or 5 trim pots that need to be adjusted all seem to interact with each other. The whole thing was very frustrating. In the end I simply adjusted them based on what I saw on the screen until I found a combination that seemed to be acceptable to me. I would love to have someone who has actually done this walk me through the confusing parts in the manual.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: Tuesday, February 11, 2020 8:47 PM
To: TekScopes@groups.io
Subject: [TekScopes] Any known issues with the 577?

So along with the 576’s that I am trying to rebuild It seems that a 577 D1 and decided to call my lab its resting place for now. It is in pristine condition given its age and the chips are date coded 91 so it seems to be one of the very late models. The good news is the tube is nice and bright with good visibility at about ½ intensity. They only issues I have found with it so far was the storage switches were slightly gummy and needed to be cleaned so they have been drenched in and exercised. Also it seems the looping capacitor in the 177 has locked complete solid other then that all the controls “feel” free and mobile. And there is 0 dust in the unit it looks like it has sat on a shelf for 30 years. Is there any known faults in a 577 like there are in a 576 that I need to worried about for this unit to be serviceable for the long haul? If there is noting there and I can repair the 177 I am going to run it through the performance check and Cal procedure then learn how to maximize its potential on the bench.





--
Dennis Tillman W7PF
TekScopes Moderator


Re: 11301/11302 in the Bay area

Clark Foley
 

Jerry, I am glad that you found the Preliminary Service books. Kurt R. was very generous to feed those beasts to the document scanner. Although the books are preliminary, they are not too far from what went to production. These books were prepared for training the service personnel.

I have the film images of the assembled boards known as Kodagraphs. I don't recall if anyone has posted these. These are necessary to locate the components and verify the trace routing/wiring. The image files are huge; so, let me know which board you think you need and I can post it or email it.

By the way, all of the original factory calibration constants are/were stored in flash memory on the 11300 series scopes. If the scope when through a proper servicing, the flash would have been updated to reflect any new hardware or significant calibration change. You should be able to get the thing to show signs of life without the need to cal it from scratch.


Re: Push-push switch repair (need some theory of operation)

EJP
 

Well I did this yesterday and it was even easier than expected. Removal was just a matter of solder-sucking and wicking. Heat gun didn't work a damn. If my desoldering gun had been working it would have been even easier, but it wasn't. Insertion was just a matter of tack-soldering a pin at each end with the PCB vertical, then fllipping it horizontal and going over each hole. Plenty of solder in each hole, as some of them have connections on the top side, and the holes aren't through-plated. Did the switches one at a time so I could inspect the topside soldering of at least one of them on the inside where they meet.

I didn't bother with the green spacers as they wouldn't fit on the flat pins on the new switches. Fit to the switch shafts was perfect.

I sourced the switches for about $A6.50ea from X-On, which is the Australian version of Mouser. They used to have an MOQ of 25 on them but it dropped bo 2 between the two times I looked.

Only remaining issue with the 7CT1N is that with PNP selected the dot is at bottom right, not top right. Am I right in thinking this is controlled by S70D, which is the part nearest the latch? All connections look OK and seem functional considering things like resistance to ground that should and shouldn't occur in the two positions. It's actually not a showstopper, as I can always adjust the vertical offset myself, but it's annoying.

EJP


Any known issues with the 577?

Eric
 

So along with the 576’s that I am trying to rebuild It seems that a 577 D1 and decided to call my lab its resting place for now. It is in pristine condition given its age and the chips are date coded 91 so it seems to be one of the very late models. The good news is the tube is nice and bright with good visibility at about ½ intensity. They only issues I have found with it so far was the storage switches were slightly gummy and needed to be cleaned so they have been drenched in and exercised. Also it seems the looping capacitor in the 177 has locked complete solid other then that all the controls “feel” free and mobile. And there is 0 dust in the unit it looks like it has sat on a shelf for 30 years. Is there any known faults in a 577 like there are in a 576 that I need to worried about for this unit to be serviceable for the long haul? If there is noting there and I can repair the 177 I am going to run it through the performance check and Cal procedure then learn how to maximize its potential on the bench.


Re: Tek 576 Curve Tracer USB port to a cpu ... ?

 

Hi Garp,
<SNIP> His Tek 576 plots on the laptop screen seem quite convincing and useful...

There were many comments about this a month ago. The 576 plots on the laptop are the most plausible aspect of whatever this person was attempting to demonstrate. It is a very primitive display. At a minimum he could have calculated and displayed the voltage and current of each graticule division along the left and bottom axes, overlaid the base current next to each step of the characteristic curves, and added useful information. Instead it adds nothing. It simply repeats the info from the 576 readouts and switch settings. It is nice documentation if you are keeping a lab notebook, but if you are a casual user of the curve tracer the axis scales and the overlays makes understanding the results easier.

I would also add:
* Every aspect of this is so crude and amateurish that you could not even call it a "prototype". The kindest thing I would say about it is that it was done as "a proof of concept".
* Alarm bells were going off in my head as I looked at this and the other web site pictures and info because they were deliberately being secretive.
* In order to capture all the information they show on the laptop they have to make connections to many places inside the 576.

Conclusion: Given the extremely amateurish nature of everything I can see they did and the secrecy I wouldn't touch one of these things.

I do admire the person who had the idea. It is a very good one and he should keep at it. I think he will have a very bright future in electronics. He reminds me of myself when all I wanted to do when I was 20 was to design my own oscilloscope.

Fortunately I did not know that when Barrie Gilbert was about the same age he showed up at Tek with a SAMPLING OSCILLOSCOPE he designed. Finding out things like this is a very humbling experience.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of garp66
Sent: Tuesday, February 11, 2020 8:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek 576 Curve Tracer USB port to a cpu ... ?


The eBay seller of the Tek 576 with USB is still listing ....
perhaps he has multiple units...

His Tek 576 plots on the laptop screen seem quite convincing and useful...

(eBay search " Tektronix 576 USB " ):
https://www.ebay.com/itm/Tektronix-576-Semiconductor-Curve-Tracer-1-Yr-Warr-Calibrated-USB-interface-CRT/302445112576?hash=item466b222d00:g:E5MAAOSw-0xYhVJm

I did not get a reply *when* I queried the Seller for more information about his interface to the Tek 576.

-- Did anyone else try to get a reply ?







--
Dennis Tillman W7PF
TekScopes Moderator


Re: 11301/11302 in the Bay area

Jerry
 

ha, for the heck of it, I looked for the service manual again and I found one! A preliminary service manual for the 11301/11302. Go figure.


11301/11302 in the Bay area

Jerry
 

Hello, Every now and then I post that I'm looking for an 11302 in the SF bay area. I don't need any plug-ins, just a functioning frame. I have one that is defective and I'm unable to figure out the issue. The symptoms are that I get double traces so there is a problem in the triggering or something. All the power is fine. No ripple to speak of. I think at a minimum it needs new NVRAM, assuming it has such. If anyone has one they would like to unload, please send me a note. Or if anyone has the service manual, again, I'd appreciate a copy or a pointer to the same.

Jerry


Re: Installing CRT into Tektronix 531A

Chuck Harris
 

It doesn't much matter. Add a splash of vinegar to a cup of
water.

As to the tubing spacer, I just warm the tubing, and stuff
a piece in that is a little larger OD than the gap.

If you split the tubing down the middle, it allows you to
handle spaces that are between two walls thick and one wall
thick. The former curvature adds springiness.

-Chuck Harris

Brenda via Groups.Io wrote:

Thanks everyone for your suggestions! I really like Chuck's suggestion and I would see no reason why it won't work. I just have to find one with the right thickness and split it and cut it to size. Chuck, if I may ask, what ratio should I use for the mix for the water/vinegar soak? I would really like to reuse that ring for my 533A.

However, I thought that I would just be able to throw that CRT into my 531A and power it up but that's not going to happen right away sadly to say. I have found that the screw that secures the rear of the shield has been sheared off, (Probably why the original CRT shattered), and after more vacuuming I found that 4 electrolytic caps are leaking a white substance where the leads go through the bottom, so I am considering these caps to be bad. On top of that, the fan barely turns so I need to figure the best way to clean it and the right oil. But I will bring this oldie back to life!

Brenda




Re: Installing CRT into Tektronix 531A

Brenda
 

Thanks everyone for your suggestions! I really like Chuck's suggestion and I would see no reason why it won't work. I just have to find one with the right thickness and split it and cut it to size. Chuck, if I may ask, what ratio should I use for the mix for the water/vinegar soak? I would really like to reuse that ring for my 533A.

However, I thought that I would just be able to throw that CRT into my 531A and power it up but that's not going to happen right away sadly to say. I have found that the screw that secures the rear of the shield has been sheared off, (Probably why the original CRT shattered), and after more vacuuming I found that 4 electrolytic caps are leaking a white substance where the leads go through the bottom, so I am considering these caps to be bad. On top of that, the fan barely turns so I need to figure the best way to clean it and the right oil. But I will bring this oldie back to life!

Brenda