Test Equipment Anonymous (TEA) group therapy thread

[TERRA Operative]

I bought parts from Keysight for my 3458A (and some other bits) which were delivered today.

Link here to avoid double posting..
https://www.eevblog.com/forum/metrology/agilent-3458a-i-joined-the-club/msg5809605/#msg5809605

Spending proper money, but it's worth it for this one. My boss is already lining up the work for it....

[Vince]

I bought parts from Keysight for my 3458A (and some other bits) which were delivered today.

Link here to avoid double posting..
https://www.eevblog.com/forum/metrology/agilent-3458a-i-joined-the-club/msg5809605/#msg5809605

Spending proper money, but it's worth it for this one. My boss is already lining up the work for it....

Well in this case boss has to pay for it all, great ! 
Obviously he will also pay to calibrate it at great expense.
It's very kind of you to spend time doing his job, searching for old gear to save him money.

[TERRA Operative]

Yep, these things are on the cards.

The value this 3458A brings far outweighs the cal etc costs, so something is being worked out.

[factory]

The wasteful dump I work for, will never get any help from me with my TE, even if they promised to pay me, they are well known for not paying invoices on time anyway. Plus I wouldn't want my TE sending to that shite cal sales company tre5c@l.

David

[Cyclotron]

Opps I did it again. Valhalla Scientific 2701C arrived. Now to find a place for it.

I'm not sure what the info on the tape means.  Maybe Version 4?  I should have looked harder to try to date the unit but haven't inspected any parts yet.

[m k]

The corner from where the TO-3 stone is missing.
Is it for earlier version of front panel?

[wkb]

The corner from where the TO-3 stone is missing.
Is it for earlier version of front panel?

Quite a few parts are not installed in that corner. Quite mysterious to have a TO3 heatsink without a device though?

[AVGresponding]

The wasteful dump I work for, will never get any help from me with my TE, even if they promised to pay me, they are well known for not paying invoices on time anyway. Plus I wouldn't want my TE sending to that shite cal sales company tre5c@l.

David

They can't be any worse than Pullman Instruments, surely..?

[AVGresponding]

The corner from where the TO-3 stone is missing.
Is it for earlier version of front panel?

Quite a few parts are not installed in that corner. Quite mysterious to have a TO3 heatsink without a device though?

Different current/voltage output options?

Agreed, strange to go to the trouble of fitting a heatsink if you're not populating the component

[wkb]

The corner from where the TO-3 stone is missing.
Is it for earlier version of front panel?

Quite a few parts are not installed in that corner. Quite mysterious to have a TO3 heatsink without a device though?

Different current/voltage output options?

Agreed, strange to go to the trouble of fitting a heatsink if you're not populating the component

That would be my guess to, some kind of option that has not been fitted.
Something beefy too, considering the TO3 plus heatsink.

Interesting unit otherwise!

[factory]

Very odd seeing as they didn't fit any screws to the TR202 heatsink (glued on?) and they didn't bother with a heatsink for the other imaginary TO-3 trannystor.

David

[tggzzz]

The wasteful dump I work for, will never get any help from me with my TE, even if they promised to pay me, they are well known for not paying invoices on time anyway. Plus I wouldn't want my TE sending to that shite cal sales company tre5c@l.

David

They can't be any worse than Pullman Instruments, surely..?

Out of curiosity I glanced at the Pullman website to see what they could do. Not impressed.

To find out what they can do, you have to guess what hieroglyphs mean; nothing so modern as text. When you click a hieroglyph, you don't get an answer, merely a "enquire by email popup".

Infer their business is to provide owners of 3.5digit DVMs etc with a "tick the compliance box certificate", but I'll never know that for certain.

[factory]

I see what you mean, lots of symbols, but no detailed webpages.

David

[lowimpedance]

Opps I did it again. Valhalla Scientific 2701C arrived. Now to find a place for it.

I'm not sure what the info on the tape means.  Maybe Version 4?  I should have looked harder to try to date the unit but haven't inspected any parts yet.

See here for more information regarding this model etc.

https://www.eevblog.com/forum/metrology/valhalla-2701c-schematics-100832/

[zepto]

Cool source. Odd that they didn't offer the current source as standard when it's only one range, requires few components, and has just 10V compliance.

I picked up my first LCD multimeter(Yokogawa dm7560) and first LCD voltmeter(Hioki dm7275).

I'm really impressed by the Yokogawa boot time (5s) and logging, and I like that it does not have a fan. I think graphing is better done on a PC, but the logging/export interfaces are nice. The statistics features are very nice as well. Integration times are somewhat limited. The interface is intuitive and responsive.
I'm very impressed by the performance of the Hioki, and I like that it has no ventilation. It also has a quick boot time. I don't really like touchscreens to be honest, but I like pretty much everything else about the device.

[Vince]

Yeah.... bought an external USB floppy drive. Used because faster shipping than getting it from China, same price, plus I can get to choose the brand, whereas the chinese one is generic / unknown and there is only one model available, that every seller advertises.

Anyway for 20 Euros shipped, I am now empowered... it's thrilling... USB is cool, so many cool stuff you can plug to it... no wonder it's still around nearly 30 years later, it's so practical.

I wasn't sure if that drive would even work at all on my Linux computer, or if I would have to  spend hours on forums to figure out how to get it to work.. so I was quite pleased when I plugged it in and it was instantly recognised and working ! Magic....

So I was able to make my first ever screen captures from the TDS 340A, or any scope really... look at that. Much cleaner and sharper than a crappy camera picture eh... I am loving it already.

While playing with the scope, I discovered a strange problem, see screen captures : I am feeding the scope a nice clean sine wave. If I look at it at sweep speeds up to 25µs/DIV, the trace looks normal, thin and sharp as it should. However if I crank the speed up just one notch, 10µs/DIV, or any speed above that, up to the max speed, then the trace becomes all of a sudden extremely, extreeeeemy noisy !   

Do experts know what could be causing this ? Somehow I doubt that calibrating the scope will fix that...

It's a bit of a show stopper isn't it... 

[tautech]

Try placing the trigger level within the waveform amplitude Vince.

[Vince]

I set it to 50% later on.
Scope triggers just fine, it's only the sweep speed that triggers the problem, oh pun...
Even if I don't give the scope any signal at all, a flat trace, I still get exactly the same issue.

[m k]

The corner from where the TO-3 stone is missing.
Is it for earlier version of front panel?

Quite a few parts are not installed in that corner. Quite mysterious to have a TO3 heatsink without a device though?

Different current/voltage output options?

Agreed, strange to go to the trouble of fitting a heatsink if you're not populating the component

My prediction is option IT-2, Constant Current Source.

Option LNF.
I understand the text so that the machine has a linear power.
Quite a difference.

https://mikedombrowski.com/2015/04/valhalla-scientific-2701c-dc-voltagecurrent-calibrator/

[m k]

If I look at it at sweep speeds up to 25µs/DIV, the trace looks normal, thin and sharp as it should. However if I crank the speed up just one notch, 10µs/DIV, or any speed above that, up to the max speed, then the trace becomes all of a sudden extremely, extreeeeemy noisy !

Is it same for both channels?

When signal comes out from attenuator it goes to sampler driver.
At the point both channels are connected to CAL+ and CAL- through 4053 analog switch.

The same 4053 is also switching GND/CAL something to attenuators.

Maybe that 4053 is not so stable anymore.

[TERRA Operative]

@Vince, do you get the same noise on both channels? If not, I'd be looking at CH1 Attenuator, then follow the signal through U204.

https://w140.com/tekwiki/images/4/41/070-9436-04.pdf
(Page 238)

Do these have relays like the TDS500/600/700 series scopes?

I also wonder if it is possible to upgrade the scope to a higher part number, there are some passive parts called out here and there that are different between the 340A and 360....

[AVGresponding]

The wasteful dump I work for, will never get any help from me with my TE, even if they promised to pay me, they are well known for not paying invoices on time anyway. Plus I wouldn't want my TE sending to that shite cal sales company tre5c@l.

David

They can't be any worse than Pullman Instruments, surely..?

Out of curiosity I glanced at the Pullman website to see what they could do. Not impressed.

To find out what they can do, you have to guess what hieroglyphs mean; nothing so modern as text. When you click a hieroglyph, you don't get an answer, merely a "enquire by email popup".

Infer their business is to provide owners of 3.5digit DVMs etc with a "tick the compliance box certificate", but I'll never know that for certain.

You can find out a bit more using the UKAS site resource: https://www.ukas.com/find-an-organisation/browse-by-category/?cat=708

Our lot use them, so it's where I have to go if I want a free one. Fine for, as you say, 3.5d and the like (our stuff is all installation testers, PAT machines etc), but I don't put a huge amount of credence to the certificate they issued for my 8840A.

Incidentally, they are who Fluke UK referred me to for spare parts service, make of that what you will

[Vince]

@Vince, do you get the same noise on both channels? If not, I'd be looking at CH1 Attenuator, then follow the signal through U204.

https://w140.com/tekwiki/images/4/41/070-9436-04.pdf
(Page 238)

Do these have relays like the TDS500/600/700 series scopes?

I also wonder if it is possible to upgrade the scope to a higher part number, there are some passive parts called out here and there that are different between the 340A and 360....

The problem is 100% the same on both channels, so 99% of the analogue stuff is ruled out right there. Gain setting has no influence.
The issue is triggered by a change in sweep speed. Slower than 25µs/DIV it's perfect, anything faster than that, lots of noise.

So, we need something that takes the acquisition clock as an input, that takes both channels / frontends as inputs, and has the ability to have an influence on what the signal will look like on the screen...

In the block diagram I can see only one suspect that fits the bill... the sampler chip, schematic  A5 page 244.
Something in there is misbehaving, so I would need to probe in there. No time for that right now, so the scope will go to storage for now.

The goal right now is to keep moving, on restoring a select few of my old Tek boat anchors, and getting rid of some vintage TE to free space.
Troubleshooting the more recent, digital stuff will be later... hopefully this year, though.

[flashover]

Hi, my name is flashover, and I think I might belong here.
Now the proud owner of these shiny bits of gear! I've written up a more detailed prose here (so I don't create too much clutter).

• Rigol DHO-804 Oscilloscope
• Rigol DP-711 Programmable Power Supply
• Andonstar AD407 Digital Microscope

[tggzzz]

Hi, my name is flashover, and I think I might belong here.
Now the proud owner of these shiny bits of gear! I've written up a more detailed prose here (so I don't create too much clutter).

• Rigol DHO-804 Oscilloscope
• Rigol DP-711 Programmable Power Supply
• Andonstar AD407 Digital Microscope

Welcome, and since that is worth being a separate topic, it is probably better have avoided getting it lost here.