Test Equipment Anonymous (TEA) group therapy thread

[Mortymore]

About the U800 on the Tek 24XX scopes, I didn't know that there was a replacement board.

http://www.davmar.org/TE/Tek2465/lafay.html

[WastelandTek]

About the U800 on the Tek 24XX scopes, I didn't know that there was a replacement board.

http://www.davmar.org/TE/Tek2465/lafay.html

(Attachment Link)

my understanding is that the files for this are incomplete and the creator is unresponsive

would love to be shown to be wrong on this

[grizewald]

Turns out it’s not rocket science to build your own 1GHz sampling head 

Deceptively simple? That circuit is way beyond my skill level, but I suspect there's more to it than meets the eye.

[bd139]

Hold my beer 

(I may build a simpler one to get 100Mhz out of the HM307 to start with as I’ve got the right bits floating around I reckon).

[Zucca]

Got my weekly Chinesium cookie today:



hope the wife will appreciate it... I hope...

[edavid]

About the U800 on the Tek 24XX scopes, I didn't know that there was a replacement board.

http://www.davmar.org/TE/Tek2465/lafay.html

(Attachment Link)

my understanding is that the files for this are incomplete ant the creator is unresponsive

A bigger problem is that the BOM cost is more than buying a good used U800 (or a complete working 2445 on a good day).

(It's been quite a while since I've seen a U800 failure though.  I think all the ones that were going to fail, have already failed.)

[Mortymore]

...

(It's been quite a while since I've seen a U800 failure though.  I think all the ones that were going to fail, have already failed.)

And I hope you're right 

[worsthorse]

...

(It's been quite a while since I've seen a U800 failure though.  I think all the ones that were going to fail, have already failed.)

And I hope you're right 

I second that.

[med6753]

...

(It's been quite a while since I've seen a U800 failure though.  I think all the ones that were going to fail, have already failed.)

And I hope you're right 

I second that.

I third that. Needless worry. Keep it cool and leave it alone. 

[WastelandTek]

A bigger problem is that the BOM cost is more than buying a good used U800 (or a complete working 2445 on a good day).

It's not always about money.

I frequently put more into boat anchors than they are strictly worth.  I suspect many of us do, and what with the 2465B being widely considered as the finest analog scope ever made...well...having an option to keep them running would sure be nice.

I think when I win the lottery I may start a business recreating the most unobtanium Tek parts, those trigger tunnel diodes for the 400s come to mind.  This business will almost certainly run at a loss, for tax purposes you understand.

[mnementh]

...(It's been quite a while since I've seen a U800 failure though.  I think all the ones that were going to fail, have already failed.)

And I hope you're right 

Not me. I need parts mules. 

mnem
And so my 2465 Army grows...

[Specmaster]

Anyone looking for a small form factor scope in the UK, London / South Eastern UK area might like to consider this, spotted tonight on Gumtree.

https://www.gumtree.com/p/for-sale/vintage-ussr-c1-73-oscilloscope-fully-working-clean-in-and-out/1365979592?utm_source=savedsearches&utm_medium=email&utm_campaign=GT.TRIGGER.SA&utm_content=none&utm_source=salesforce&utm_medium=email&utm_campaign=Search_Alert&utm_content=EMAIL_ALERTS_TRACK_MULTI

[alextwin007]

These are the exact kind of things I keep an eye out for.  Unfortunately I'm in the US.
These tiny Russian scopes never seem to be in the US, I can't image why

Anyone looking for a small form factor scope in the UK, London / South Eastern UK area might like to consider this, spotted tonight on Gumtree.

https://www.gumtree.com/p/for-sale/vintage-ussr-c1-73-oscilloscope-fully-working-clean-in-and-out/1365979592?utm_source=savedsearches&utm_medium=email&utm_campaign=GT.TRIGGER.SA&utm_content=none&utm_source=salesforce&utm_medium=email&utm_campaign=Search_Alert&utm_content=EMAIL_ALERTS_TRACK_MULTI

[tautech]

Anyone looking for a small form factor scope in the UK, London / South Eastern UK area might like to consider this, spotted tonight on Gumtree.

https://www.gumtree.com/p/for-sale/vintage-ussr-c1-73-oscilloscope-fully-working-clean-in-and-out/1365979592?utm_source=savedsearches&utm_medium=email&utm_campaign=GT.TRIGGER.SA&utm_content=none&utm_source=salesforce&utm_medium=email&utm_campaign=Search_Alert&utm_content=EMAIL_ALERTS_TRACK_MULTI

MartinM chases little scopes too but might already have this one.

[mnementh]

I make that ~296MHz equivalent bandwidth... suspiciously high? Maybe not. Seems to be within the realms of possibility for this little box: https://www.eevblog.com/forum/beginners/oscilloscopes-to-stay-away-from-(spec-tek-2337-question)/msg46880/#msg46880

Edit: also have to say this. I'm not sure why I didn't buy one of these scopes before. It's just perfect.

Remember, the 2445 is the scope that wanker 2465b likes to homunculate into a "2465"; there's a reason he can claim near equivalent performance from his bastard children.

mnem
 

[Specmaster]

Anyone looking for a small form factor scope in the UK, London / South Eastern UK area might like to consider this, spotted tonight on Gumtree.

https://www.gumtree.com/p/for-sale/vintage-ussr-c1-73-oscilloscope-fully-working-clean-in-and-out/1365979592?utm_source=savedsearches&utm_medium=email&utm_campaign=GT.TRIGGER.SA&utm_content=none&utm_source=salesforce&utm_medium=email&utm_campaign=Search_Alert&utm_content=EMAIL_ALERTS_TRACK_MULTI

MartinM chases little scopes too but might already have this one.

Just been watching a video on YouTube (a car channel) with a Welsh YouTuber who is over in New Zealand doing an exploration of the island and is currently in North island, which is where I believe you are. He has just driven coast to coast across from West to East along the Forgotten World Highway and the scenery is beautiful, here is a link to that drive if you're interested.

  

[tautech]

Yeah Spec, did the forgotten highway with the missus a few years ago. It is scenic but some is bloody steep and only good to farm sheep or mountain goats on !
Runs between Tauriminui and Stratford which is close to New Plymouth. Basically middle of our north island to the west coast.
Few hundy miles south of where we are in Auckland.

Wanna real wilderness drive take SH38 through the Urewera's.
https://www.doc.govt.nz/parks-and-recreation/places-to-go/east-coast/places/te-urewera/

[worsthorse]

I make that ~296MHz equivalent bandwidth... suspiciously high? Maybe not. Seems to be within the realms of possibility for this little box: https://www.eevblog.com/forum/beginners/oscilloscopes-to-stay-away-from-(spec-tek-2337-question)/msg46880/#msg46880

Edit: also have to say this. I'm not sure why I didn't buy one of these scopes before. It's just perfect.

Remember, the 2445 is the scope that wanker 2465b likes to homunculate into a "2465"; there's a reason he can claim near equivalent performance from his bastard children.

mnem
 

muahahaha!

he's also the guy selling the seven hundred dollar TM plugins with ad copy that provides a service for defrauding foreign governments by accepting payment on the side and sending a false invoice. 

when will people figure out that a person that offers to cheat on your behalf is just as likely to cheat you directly, given the chance?

[bitseeker]

I defy any of these audio jerks to tell an audible difference between a run of the mill RCA 12AX7 and an Amprex 12AX7. 99.9% of them can't. It's all in their pea brain head. 

Not only that, but by the time you accumulate the liquidity to acquire better and better audio gear, the more your hearing has deteriorated from age and exposure. It's quite an ironic arrangement.

[bitseeker]

I think the insertion into appropriate orifice's might help the verbal diarrhea that is Audio Foolery. 

Audio Noise Stoppers anyone The Description is important to read as it explains the pseudo non sciencey stuff.... eBay auction: #293078533933



If you were on Discord on the weekend you would already know this too (Attachment Link)

Thanks, bean. That listing gave me a good laugh! They are nice dust covers, though. Maybe I should put some on my DMMs.

[mnementh]

Oh, bitseeker... you’re just so adorable when you’re a couple pages behind...

mnem
*tosses bitseeker some fire extinguishers and a flak jacket*

[bitseeker]

Aw, shucks. The pages just go by so quickly!

[beanflying]

As we enter the 1980's lets pause and remember Big Hair and the Decade Fashion Failures 

[bitseeker]

As we enter the 1980's lets pause and remember Big Hair and the Decade Fashion Failures 

 

You can park 'em right here

[AVGresponding]

Ok pulse generator take two. I was digging in the cupboard of doom and found my old JW pulse generator (2n2369 avalanche mode). Alas I couldn't find a power supply or enough things to plug together that had plugs to get the required 100V to give this thing a kick (70V my ass). Quick breadboard boost converter was developed with an IRF510 running dangerously over Vds(max) (fingers in ears) driven by the 3312A. It worked though. Voltage regulation was provided by dragging gate to ground using a 2N3904 and a resistive divider on the output.



This was plonked into the pulse generator that lives in the end of a Pomona box:



Getting busy on the bench now



And the results are pretty good!:



I make that ~296MHz equivalent bandwidth... suspiciously high? Maybe not. Seems to be within the realms of possibility for this little box: https://www.eevblog.com/forum/beginners/oscilloscopes-to-stay-away-from-(spec-tek-2337-question)/msg46880/#msg46880

Edit: also have to say this. I'm not sure why I didn't buy one of these scopes before. It's just perfect.

Also some circuit notes. MOSFET = IRF510. Standard boost topology. Inductor is from junk box around 6.8mH (way too high but it'll do). 10R in series with gate or it oscillated like mad. 470k/2.2k divider. 100uF decoupling cap. 1uF film across output.

You need an Electrophoresis power supply...   

Seriously though, these things are useful, though I admit the 2.5kV max on mine is... overkill, hopefully not literally! Most have a max of several hundred volts, at least the used ones I've seen for sale.