Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

There is a nice looking one for EUR 79.- in .de, ships worldwide (including UK  )

https://www.ebay.com/itm/223635588087

I’m too cheap. They turn up here regularly for pocket money. 

Patience is the game.

Someone is selling some later 100Mhz ones here but at the £300 mark 

Try looking on Shpock and Gumtree, often turn up there, but as always for more money but most people are willing to do a deal as they zero idea of their true worth.

Sent from my POT-LX1 using Tapatalk

[tggzzz]

Edit: it's really embarrassing that an ass end 20MHz scope with bare minimum features is actually ranking high on the "just works" list

I'd have thought it more embarrassing that that concept is new to you

More seriously, good triggering is vital to any scope - or logic analyser for that matter.

[BU508A]

This one is around 60.- Euros but you can make an offer.
It claims as "for parts not working"

https://www.ebay.com/itm/HAMEG-HM-605-Oszilloskop/283555696791

But what confuses me: it comes with a yellow screen. Never saw a Hameg before with a yellow screen. 

[tggzzz]

Maybe bd139 likes to hunting down issues he would not have with better equipement?

Nah. He just likes re-making old mistakes.

Maybe I shouldn't point out this https://www.gumtree.com/p/hobbies-collectibles/oscilloscope-/1352086274 which is only a stone's throw from him. Claimed to be working, too.

[bd139]

This one is around 60.- Euros but you can make an offer.
It claims as "for parts not working"

https://www.ebay.com/itm/HAMEG-HM-605-Oszilloskop/283555696791

But what confuses me: it comes with a yellow screen. Never saw a Hameg before with a yellow screen. 

I think they're optimised for slow scan stuff. I've seen a few around like that. Same with Telequipment. It was a phosphor option. Edit: P12 I think.

Maybe bd139 likes to hunting down issues he would not have with better equipement?

Nah. He just likes re-making old mistakes.

Maybe I shouldn't point out this https://www.gumtree.com/p/hobbies-collectibles/oscilloscope-/1352086274 which is only a stone's throw from him. Claimed to be working, too.

Ahh all the joy of tunnel diodes, cam attenuators and "fuck you mr repair dude" engineering and none of the bandwidth to make you feel better 

[PA0PBZ]

But what confuses me: it comes with a yellow screen. Never saw a Hameg before with a yellow screen. 

Searching for HM-605 pictures on google about 10% has a yellow screen.

[bd139]

Edit: it's really embarrassing that an ass end 20MHz scope with bare minimum features is actually ranking high on the "just works" list

I'd have thought it more embarrassing that that concept is new to you

More seriously, good triggering is vital to any scope - or logic analyser for that matter.

Oh it's not new to me for sure. The Rigol has exceptionally good triggering for the money but not in this edge case. Everything has some compromise in it somewhere and you usually find it at the most inconvenient time. The 4x5s for example, while fairly good, really don't work well until they've been warmed up for at least 20 minutes and they genuinely suck at triggering on slow rise times (tens to hundreds of milliseconds rise time) even in DC coupled trigger mode. It's not so much that they don't trigger it's just fiddly as hell trying to persuade the things to do it and keep them triggering.

The Philips PM3217 has one of the best triggers out there to be honest and takes half the time to warm up to the point it doesn't suck as the 4x5's do.

[tggzzz]

I noticed the same thing. The 475A Trigger is finicky until warmed up but once warm is stable. And yes, the 465B Trigger is good right from the get go. Same with the 485 (The one that the Trigger works  )

Go on, ramp up the frequency until the 485 no longer triggers well.

Mine was OK at 1GHz, and was limited by the waveform's amplitude being only ~0.2divisions peak-peak.

[BU508A]

But what confuses me: it comes with a yellow screen. Never saw a Hameg before with a yellow screen. 

Searching for HM-605 pictures on google about 10% has a yellow screen.

Yes, now I saw that, too. It was a surprise to me, because all Hamegs I saw before, had a green or blue screen.
Maybe this is because I've used in the past only 203 or 205 or, occasionly, the 100MHz ones from a friend of mine.
You live and learn. 

[tautech]

The Rigol has exceptionally good triggering for the money but not in this edge case.

And exactly what is this edge case ? 

Ways to replicate it ?

[BU508A]

The Rigol has exceptionally good triggering for the money but not in this edge case.

And exactly what is this edge case ? 

Ways to replicate it ?

Building a Nixie-clock with a transistor-only ring counter 

[med6753]

My, my...Europe sure is busy this morning. 2 pages already. Almost can't keep up. 

[BU508A]

My, my...Europe sure is busy this morning. 2 pages already. Almost can't keep up. 

Can't sleep, so you are looking for a lullaby here in the TEA thread? 

I've discovered, this won't play very well ...   

[med6753]

My, my...Europe sure is busy this morning. 2 pages already. Almost can't keep up. 

Can't sleep, so you are looking for a lullaby here in the TEA thread? 

I've discovered, this won't play very well ...   

It's nearly 0500 hours here, my normal wake up time. Although I have been known to putter around for a while and then go back to bed. 

[bd139]

The Rigol has exceptionally good triggering for the money but not in this edge case.

And exactly what is this edge case ? 

Ways to replicate it ?

Event happens every one second. Rising edge is the top 20% of a sine spanning 0-0.6V peak. It just won't trigger on it. I can zoom timebase out until it's slow enough then single capture and then zoom it though. I think the dy/dx isn't sharp enough for it to work out it's a trigger event. I've tried all rising and trailing edge triggers in it.

To be clear here I've actually solved this by building a quicky LM311 circuit set to flip at ~300mV with 100mV or so of hysteresis on a breadboard and using that to trigger it. That works fine! 

[tautech]

Auto won't work, what about Single ?

[bd139]

Playing with this again this morning and nope, single doesn't trigger. Or I thought it didn't. It DOES trigger on chan 3 and 4 but not channel 1 and 2 which is both interesting and worrying at the same time.  I'm wondering if there's a hardware issue with this one. 

Edit: running self cal again on it.

[tautech]

What s/div setting ?

[bd139]

500ms/div ... 100mV/div vertical.

Self cal has passed and it actually triggers now on 1/2 . Looks like something analogue had drifted off ffs. Literally only did self cal on Sunday. piece of crap.

Looking at Keysights again now 

[tautech]

500ms/div ... 100mV/div vertical.

That's in ROLL mode so NO triggering until the display is filled then it should trigger no prob and maybe even get into Zoom mode where you can examine the trace in further detail.

Anyways, would love to see a screenshot if you can.

[BU508A]

500ms/div ... 100mV/div vertical.

Self cal has passed and it actually triggers now on 1/2 . Looks like something analogue had drifted off ffs. Literally only did self cal on Sunday. piece of crap.

Looking at Keysights again now 

This should fit your use cases. Perhaps. 

https://www.ebay.com/itm/253848130391

Edit:

Why won't you buy a Siglent? I've heard, we're having here in the forum some very competent people regarding to Siglent gear.   

[bd139]

500ms/div ... 100mV/div vertical.

That's in ROLL mode so NO triggering until the display is filled then it should trigger no prob and maybe even get into Zoom mode where you can examine the trace in further detail.

Anyways, would love to see a screenshot if you can.

It's not in roll mode. Objectively I placed the trigger 1 div into the left side of the screen and waited. It is supposed to trigger there, then fill the remainder of the sample memory and chuck it on the screen instantly after the trigger. But it was doing full captures which were slowly sliding left by half a div per capture (auto mode) and no trigger indicator was happening. In single mode, bugger all.

My purpose here was to grab a monostable trigger event and then measure the delay.

Alas doing a self cal seems to have fixed it now (or power cycling it - who knows?!?!) but that's just shit.  Can't screenshot it now because the damn problem has gone away. I was going to video it this morning. Grr.

Edit: I validated trigger level, trigger mode, trigger channel several times thinking it was me but it appears it wasn't this time. It usually is me! 

500ms/div ... 100mV/div vertical.

Self cal has passed and it actually triggers now on 1/2 . Looks like something analogue had drifted off ffs. Literally only did self cal on Sunday. piece of crap.

Looking at Keysights again now 

This should fit your use cases. Perhaps. 

https://www.ebay.com/itm/253848130391

I don't think even both my kidneys are worth that 

[tautech]

500ms/div ... 100mV/div vertical.

Self cal has passed and it actually triggers now on 1/2 . Looks like something analogue had drifted off ffs. Literally only did self cal on Sunday. piece of crap.

Looking at Keysights again now 

This should fit your use cases. Perhaps. 

https://www.ebay.com/itm/253848130391

Nope, this one is a better deal as it's $250k off ! 
https://www.ebay.com/itm/Keysight-Used-DSAX95004Q-Digital-Signal-Analyzer-50-GHz-4-Ch-80-GSa-Agilent/173981254946?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20160323102634%26meid%3D3cbff00187e24fee801f9c31042d461e%26pid%3D100623%26rk%3D4%26rkt%3D6%26sd%3D253848130391%26itm%3D173981254946%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100623.m-1

[tautech]

500ms/div ... 100mV/div vertical.

That's in ROLL mode so NO triggering until the display is filled then it should trigger no prob and maybe even get into Zoom mode where you can examine the trace in further detail.

Anyways, would love to see a screenshot if you can.

It's not in roll mode. Objectively I placed the trigger 1 div into the left side of the screen and waited. It is supposed to trigger there, then fill the remainder of the sample memory and chuck it on the screen instantly after the trigger. But it was doing full captures which were slowly sliding left by half a div per capture (auto mode) and no trigger indicator was happening. In single mode, bugger all.

My purpose here was to grab a monostable trigger event and then measure the delay.

Alas doing a self cal seems to have fixed it now (or power cycling it - who knows?!?!) but that's just shit.  Can't screenshot it now because the damn problem has gone away. I was going to video it this morning. Grr.

Edit: I validated trigger level, trigger mode, trigger channel several times thinking it was me but it appears it wasn't this time. It usually is me! 

Still if it's working OK now it would be good to see what you had to get.
Did you play with Holdoff at all ?

[bd139]

Nothing exciting. Just a relatively sloppy wet pulse triggering a monostable 

It wasn't triggering at all so holdoff wasn't any use.

I've just spent ten minutes trying to reproduce it now to no avail.

Only thing I can think of that may have caused this is an offset issue somewhere which caused a disparity on trigger level. This would make sense as it went away after cal but I'd have expected to see a zero drift for that. It was unlikely a gain drift either. I'm wondering if the user cal process fucked up when I did it on Sunday?

Edit: anyway got to dump this issue. My mother has just had her cateracts done so I'm off to the hospital now to do the ferrying...