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Re: Anyone interested a addon plugin that enable you to use 7000 plugins on modern digital scope

 

HI Yang,
WOW What a great idea! Congratulations on coming up with a wonderful project that will let everyone take advantage of some great Tek plugins.
At least at first, to prove your concept is sound, pick the 7A22 to interface to. It has the lowest bandwidth and should be the least challenging.
I think your only challenge will be with the 7A13 because the bandwidth is 110MHz which requires a high speed buffered output to the modern digital scope.
If you succeed with these initial four plugins many more will become possible as well.
I assume there is no plan to include the on-screen readout but without it this is still a great idea.
For a future version I would like to suggest merging two boards together so they can share one power connector for the dual width 7S14 and 7S12.

Dennis Tillman W7PF
TekScopes Moderator


Re: Tek extenders

FAZ
 

I'm interested... what series scopes are they for?

glad you got to him before he committed sacrilege


Re: Tek extenders

nonIonizing EMF
 

I'd like one also though don't need and am wondering how much he's asking since would be more a rescue in my situation.


Re: Tek extenders

@0culus
 

I, too, would be potentially be interested in 7k series extenders.


Re: A z-axis interference modulation on a 7704A scope

Albert Otten
 

Hi Ernesto,

I know this phenomena but in the 7704A on my workbench it's hardly or not noticeably.
There is no reason to suspect the HV. In the 7704A the HV transformer primary is fed with a square wave from the main SMPS, so at the SMPS frequency.

Albert


Re: Tek extenders

 

I am willing to buy one for more than the scrap value of any gold on it.

Ernesto


A z-axis interference modulation on a 7704A scope

 

My 7704A scope is working correctly.
But all along I have noticed an intensity modulation riding on the trace.
First I assumed that it could be the random readout happening during the sweeps,
but I turned the readout to happen at the end of sweeps, and the effect remained.

I placed an oscilloscope probe against the HV supply to pick up the 25 kHz square wave of the inverter, and triggered on it.
On another trace with zero signal, it became very visible that the intensity modulation is the 25 kHz wave.

I don't have another 7000 series scope to compare with, therefore I ask if any of you have a similar experience, which could mean that the effect is normal in these scopes.
If so, I won't worry because it is not a big deal, since turning up the intensity this disappears, and it is only noticeable at some sweeps.
Otherwise, could this be the effect of some broken or aging capacitor in the grid restoration circuit?

Regards,
Ernesto


Re: Anyone interested a addon plugin that enable you to use 7000 plugins on modern digital scope

Ke-Fong Lin
 

Hi Yang and Ed,

Yang, I'm definitely interested. My "target" plug-ins would 7A22 differential amplifier and 7L5 spectrum analyzer.
About the 7L5, it is 2 "slots" and would require support for "horizontal" signal. Any plan for that?
Also, does your PCB support read-out?
I've also a 7000 extender project but only for repair/calibration purpose.
Your is much more elaborate, I'd be delighted if I can use my 7L5 "standalone".

Best regards,


Re: Anyone interested a addon plugin that enable you to use 7000 plugins on modern digital scope

Ed Breya
 

What are you going to do about the plug-in edge connector? Have you found a standard type that will work?

Ed


577 Curve Tracer Left-Right Switch Repair for 177 Test Fixture

robeughaas@...
 

Many 577 curve tracers have broken left-right switches on the 177 test fixture. The vintageTEK Museum has located a supply of replacement mechanisms. It is possible to unscrew the contact assemblies in the 177, remove the old mechanism and slide in the new. Access to the inside screws requires removing and replacing the looping comp variable cap and the shunt resistor plate (which is socketed). Photos are here: https://groups.io/g/TekScopes/album?id=246557

We will make these available for $40 postpaid. Please reply to this post if you are interested.

--
Bob Haas


Re: Anyone interested a addon plugin that enable you to use 7000 plugins on modern digital scope

Leo Potjewijd
 

I would be.
Looks like a pretty neat design, too.
What would you make available?


Re: 577 magic smoke :-(

Reginald Beardsley
 

Paul,

Thanks! The culprit is C581 which is a dead short.

This raises the question of whether to make the repair and see if it's usable or do a complete refurb and cal. I don't have space or time right now for the latter. If I do it now it delays building my new lab. Though having Eric do it would not interfere with building the lab.

Makes me think of Dirty Harry. "Well, punk? Do you feel lucky?" It's obviously of an age where a full recap is a good idea. How much of a 577 is made of pure unobtainium?

Have Fun!
Reg


Re: Tek extenders

Mlynch001
 

If they are 7xxx they are a gold mine.

--
Michael Lynch
Dardanelle, AR


Anyone interested a addon plugin that enable you to use 7000 plugins on modern digital scope

ycui7
 

I am working on a project that generating all the necessary power for a 7000 plugins, so that you can use some 7000 plugins on modern digital oscilloscope.

https://groups.io/g/TekScopes/album?id=246549

The addon board will be installed on the back of 7000 plugins, generating +/-50V, +/-17V, and +/-5V. It also has capability yo convert the plugin's differential output to single-ended signal for consumption by modern digital scope.

Power will be provided by 20V USB-PD and converted to all requried voltage for 7000 plugins.

The current targeting 700 plug-ins are:
7A13
7A22
7S14 (requires two addon boards)
7S12 (requires two addon boards)


Anyone interested in this?


Re: 577 magic smoke :-(

Eric
 

Hey Chuck.

I might have to try that next time. I am just finishing up the recap if this ever needs to be done again should be much easier next time. The one that crapped out on me was C759 at the very bottom. I guess my mistake was working bottom to top instead of top to bottom.

Eric

On 5/7/2020 11:35 AM, ChuckA wrote:
Eric,

You don't have to remove the CRT to replace/rebuild the PS caps. You need to remove the carry handle assembly, the 2 power supply boards and the CRT wires. You can then reach down and remove the cans from the chassis.

On my 576 I removed all the cans, opened them up at the bottom crimp seal and installed new caps inside and then peened  the aluminum crimp back.

Chuck


On 5/7/2020 11:06 AM, Eric wrote:
I am currently working on a 576 and I have a 577 "in the wings waiting on some parts. I have not looked at the cal section for the 577. The 576 will be getting a full cal after a complete recap of the power supply filters. They are a nightmare to do tube needs to come out. We can E-mail more off list if you would like to talk more about it off list.

Ericsp (at) gmail.com


Re: 577 magic smoke :-(

ChuckA
 

Eric,

You don't have to remove the CRT to replace/rebuild the PS caps. You need to remove the carry handle assembly, the 2 power supply boards and the CRT wires. You can then reach down and remove the cans from the chassis.

On my 576 I removed all the cans, opened them up at the bottom crimp seal and installed new caps inside and then peened  the aluminum crimp back.

Chuck

On 5/7/2020 11:06 AM, Eric wrote:
I am currently working on a 576 and I have a 577 "in the wings waiting on some parts. I have not looked at the cal section for the 577. The 576 will be getting a full cal after a complete recap of the power supply filters. They are a nightmare to do tube needs to come out. We can E-mail more off list if you would like to talk more about it off list.

Ericsp (at) gmail.com

--
See Early TV at:

www.myvintagetv.com


Re: 577 magic smoke :-(

Eric
 

I am currently working on a 576 and I have a 577 "in the wings waiting on some parts. I have not looked at the cal section for the 577. The 576 will be getting a full cal after a complete recap of the power supply filters. They are a nightmare to do tube needs to come out. We can E-mail more off list if you would like to talk more about it off list.

Ericsp (at) gmail.com


Eric

On 5/7/2020 10:58 AM, Paul Amaranth wrote:
That's on Schematic 6

On Thu, May 07, 2020 at 07:51:27AM -0700, Reginald Beardsley via groups.io wrote:
It's a D1.

I figured out the 177 after I started reading the service manual.

I found the smoke source, CR582 on the A2 collector supply board, 200 V 1.5 A bridge rectifier, but can't find it on the schematic. It's in the board photo which allowed me to identify it.

Is there anyone on the list who refurbishes and calibrates these in the fashion that Reed Dickinson does 485s?


Re: 577 magic smoke :-(

Paul Amaranth
 

That's on Schematic 6

On Thu, May 07, 2020 at 07:51:27AM -0700, Reginald Beardsley via groups.io wrote:
It's a D1.

I figured out the 177 after I started reading the service manual.

I found the smoke source, CR582 on the A2 collector supply board, 200 V 1.5 A bridge rectifier, but can't find it on the schematic. It's in the board photo which allowed me to identify it.

Is there anyone on the list who refurbishes and calibrates these in the fashion that Reed Dickinson does 485s?
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux


Re: 577 magic smoke :-(

Reginald Beardsley
 

It's a D1.

I figured out the 177 after I started reading the service manual.

I found the smoke source, CR582 on the A2 collector supply board, 200 V 1.5 A bridge rectifier, but can't find it on the schematic. It's in the board photo which allowed me to identify it.

Is there anyone on the list who refurbishes and calibrates these in the fashion that Reed Dickinson does 485s?

Thanks,
Reg


Re: 577 magic smoke :-(

Paul Amaranth
 

It doesn't look like they used RIFA caps, pity that'd be a good culprit
for magic smoke when turned on. Probably a shorted cap somewhere.

I have a pdf of full sheet schematics that I picked up somewhere. They're
great if you have a large format printer available. Here's the link:

https://www.scribd.com/document/329797401/577d1d2-schems-f6iib

Probably should copy that into the Tekwiki.

You can swap the storage/non storage displays from a 5103. Nobody wants
those so you can find them dirt cheap. I keep a couple for spares for
my 577 (one storage, one non-storage).

Paul

On Thu, May 07, 2020 at 09:58:18AM -0400, Eric wrote:
Auto transformers can damage switch mode power supply if you set them below
the regulation voltages. Sounds like a cap went. Note serial number on the
serice manual there was a lot of revisions to this one. The 177 comes apart
pretty easy I have a late model one so don't know if it has changed but
detach it from the 577, just pull "gently" Not screwed in like the 576. Then
it is side panels first then bottom cover if I remember correctly. There is
HV ever ware in one of there and the collector supply is isolated from
chassis ground.  Did you get the D1 or the D2? The storage tube has a weird
power on sequence if it has been off for a while "2 weeks" If I recall
correct

Eric

On 5/7/2020 9:46 AM, Reginald Beardsley via groups.io wrote:
I picked up an ebay 577 from a seller who got a big lot of stuff from a company merger. He got into this because a neighbor who worked there. He knows nothing about electronics. The neighbor has since moved. A lot of the other stuff he had looked like old lab closet queens complete with 1990 inventory labels. Serial number on the 577 is B105527

The 577 was shown on ebay with a screen trace. So I was hopeful it might be working.

I just powered it up and got a trace, fiddled with a few knobs moving trace position, width, etc. Noting erratic behavior I concluded I'd need to clean the controls before proceeding further and powered it off.

Then I got the nasty scent of magic smoke. The really acrid variety. I've pulled the covers from the top/sides and base, but don't see anything obvious. The smoke seemed to come from the 177 fixture and the smell is strongest in the front of the instrument. There is a label "Interlock Disabled Internally. 25 V Max". I've not yet figured out how to open the 177.

So where to start? Obviously I don't want to apply power again until I locate the fault and correct it. I do have an isolation and autotransformer if those are potentially useful in diagnosing the source of the smoke.

I have no experience with any of the Tek curve tracers. I've worked with HV CRT supplies. A long time ago, so I'm being especially cautious as I've learned how much I've forgotten.

I'm off to track down a service manual.

Thanks,
Reg





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--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux

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