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MB connectors available at:

BSM or MB connector are apparently very hard to come by. If the unit works as intended, should I replace them with SMA ones?

On Thu, Dec 23, 2021 at 04:23 AM, Peter H wrote:

To my knowledge, and per a quick reading of the manual, the 7S12 doesn't
trigger from the sampling head (left-hand head slot), only from the right-hand
head which can be a pulser (for TDR), or an S-53 Trigger Recognizer.

Does that mean it can trigger from a S-52?

On Thu, Dec 23, 2021 at 04:24 AM, Peter H wrote:

Sorry, I also added a redirect on the wiki so clicking the link will work now.

Thanks. I printed it out for quick reference this evening when I do what you said.

Siggi's reply is a very good summary, just to amplify a couple of points:

The 2430A digitises at 100Msamples/sec, the rule of thumb is that the useful bandwidth for a single shot acquisition is 1/5th of the sampling rate so it is only 20MHz. With a stable repetitive signal you can 'fill in the gaps' with the equivalent time sampling but you still get a somewhat noisy (not fuzzy, it is only noise in the Y direction) due to the digitising accuracy. You can smooth the trace by averaging but by this time you will find the scope not very responsive for general 'probing around'.

You will find the user interface to be different from an analogue scope in the time that you spend fiddling with menus. On the plus side there are things like the envelope option for recording highest and lowest values that pick out the occasional glitch in an otherwise regular signal and you can mimic a chart recorder for very slow sweep speeds. I find this very useful for power supplies that switch themselves off just after startup.

The FPP errors and recalibration are not a serious issue, anything to do with the CCDs is going to be hard to find replacement parts. If you want to work on the scope with the case removed you need to supply extra cooling to the CCDs since they rely on the airflow in the duct formed by the PCB and the case.

All in all I would say it could be fun at a suitably low price, but don't expect it to be your main everyday scope.

Regards,

Roger

Sorry, I also added a redirect on the wiki so clicking the link will work now.

To my knowledge, and per a quick reading of the manual, the 7S12 doesn't trigger from the sampling head (left-hand head slot), only from the right-hand head which can be a pulser (for TDR), or an S-53 Trigger Recognizer.

In the cold light of day I see that I was probing on the wrong pads....

Still no -12V but not the short I though I had... I'll be back when I have better data

Dave

manuals@...

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Thanks Raymond.

Notes. I¡¯ll see how it turns out this evening.

You might try this link and see if the manual is any better:

Shaggy Dog Summary:

Bought a 7A13 plug-in , Known " not working" but no detail. Plugged it in and the 7904 stopped working...8^(

Troubleshooting trail so far:

7904 serial B257xxx. Which means it uses the "early"manual. ( later manual picks up a serial B260000)

Do the power supply voltage check drill find everything is OK ..EXCEPT the -12V is shorted to ground! Systematically unplug cables from the power supply and isolate that when the SENSE cable P83 is unplugged the short (on the power supply) goes away and the short appears to be somewhere downstream in the A2 main board. There the trail goes cold. Sch#1 shows (along the bottom for those following along in your manual) that P83 goes into to "POWER SENSE" with no actual location as to where it is connected inside. I have searched and do not see where this -12V sense line connects to any circuitry? so as to trace the short to its source, ( but I cant find things in the fridge that are right in front of me either )Possibly "GG" on the A4 logic board ???

Any help /clues appreciated

Dave

manuals@...

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Dave Manuals@... www.ArtekManuals.com

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I¡¯m looking for the military version of Troubleshooting your Oscilloscope I was told it went into deeper detail of how too step by step.

Andrew

On Thu, Dec 23, 2021 at 02:14 PM, Raymond Domp Frank wrote:

On Wed, Dec 22, 2021 at 07:46 PM, Albert Otten wrote:

I think the oscillator frequency was too low because your tube is too good.

I think there's a misunderstanding here. Stephen initially replaced the
original 200pF caps with 250pF caps. That's what caused the lower frequency.
As soon as he corrected the RC-times to match the original by correspondingly
reducing the R's, everything was right.

Raymond

Grrr, you are right Raymond! I forgot about that part of the story.
Nevertheless I think my "theory" is correct, though the differences between tube emissions might be not large enough to change the frequency by 25%.
Albert

On Thu, Dec 23, 2021 at 02:19 PM, Stephen wrote:

If¡¯s it¡¯s not fully operational, what would you consider a good price?

Repairing a complete 7S12 in TDR setup often isn't straightforward, especially with limited equipment and no spare parts. Therefore, a unit that is not fully functional would only have spare parts value.
Depending on technical and cosmetic condition, I'd consider €100 for the 7704A + 7A26 + 7B70 a reasonable price, with €150 being the absolute limit for an impeccable unit.

Raymond

Raymond,
That¡¯s exactly why I¡¯ve asked for advice on how to do an initial check to see if EVERYTHING is functioning properly.
If¡¯s it¡¯s not fully operational, what would you consider a good price?

On Wed, Dec 22, 2021 at 07:46 PM, Albert Otten wrote:

I think the oscillator frequency was too low because your tube is too good.

I think there's a misunderstanding here. Stephen initially replaced the original 200pF caps with 250pF caps. That's what caused the lower frequency. As soon as he corrected the RC-times to match the original by correspondingly reducing the R's, everything was right.

Raymond

On Thu, Dec 23, 2021 at 06:45 AM, Stephen wrote:

I¡¯ve never ever used a sampling plugin before. I wouldn¡¯t even know how to
see if it even works properly, nor where to start¡­

You have to be aware that the 7S12-set that you describe is a TDR unit, not a general purpose sampling 'scope plugin. The S-6 does not supply a trigger signal to the 'scope. A sampling 'scope needs a trigger signal, like any other 'scope. Either replace the S-6 with a sampling plugin having internal trigger pick-off, like an S-2 or an S-4, or use a Trigger Recognizer (S-53), replacing the pulse generator.
Also, be aware that sampling 'scopes are not as easy to operate and much more vulnerable to damage (static electricity) than ordinary 'scopes. Leave the input pp signal (DC+AC) below 1V for best results. When using the S-6 as a regular 'scope input, you'll need to terminate the S-6 into 50Ohm (SMA terminator).

Unless the 7S12 set is completely operational, I wouldn't consider €280 a good price.

Raymond

On Thu, Dec 23, 2021 at 01:17 AM, Raymond Domp Frank wrote:

You probably included the ":" at the end of the link. Enter the link without
it and the link works.

Raymond

Probably. I just clicked on it¡­
Thanks

On Thu, Dec 23, 2021 at 11:34 AM, Stephen wrote:

Thank you Peter, but your link links to no image¡­

You probably included the ":" at the end of the link. Enter the link without it and the link works.

Raymond

That's an interesting document on Tekwiki!