Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Just a point on the EMI filters on these. The little silver box actually contains 2/3 RIFA X2 capacitors and a common mode choke usually. RIFAs are pretty bad on their own but when you put them inside a pipe bomb, interesting things happen. We had one much newer than that in a SAN power supply and it blew its load all over the inside of the unit. I have a photo somewhere in the office I will dig out but it was a right mess.

Please do, it will be a good reference for motivational photo. 

Or at least a good storyboard frame for an episode of "Robot Chicken"... 

Doesn't mean it's not going to blow up

I had another vendor's one blow up in a Philips scope. Hissed like an angry snake. Fortunately it was burning in with the case open on the table so I got to shut the power down before it went.

They are replace on sight "if older than 20 years" disposable parts really. We're way beyond the design life.

Might be worth checking temperature of it after an hour or so. That's a good indicator. They don't run hot unless there's something wrong with them.

Interesting... the filter circuit in that video appears to be a common mode choke and some caps as a 6dB low-pass filter; guessing by that one around 0-300Hz or so is typical?

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

But on the flip side, this might be an opportunity to easily upgrade to a multistage model with better EMI and even added RFI filtering; when these 'scopes were made, the 1GHz + background noise that permeates any even marginally developed geolocation simply did not exist.

Thanks for shining a light on this mostly-overlooked aspect of our addiction! 


mnem
Mornings are not for the weak.

[tggzzz]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

[mnementh]

I am confident that the EMI filter in the 2465 is not made by Schaffner.

Seems so as the mains filtering is on another PCB.
Shown here:
https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg425034/#msg425034

The 24xx family used both with and without, just like the 22xx family. But you knew that. Here's a pic of another 2465B (Above left) from the same thread that DOES have an IEC Socket EMI filter. It still has the same filtering circuit in the A2 DC-DC board. The 2230 has a separate EMI filter board, but mine (above right) also has the IEC EMI filter; I've seen photos of other 22xx scopes with just a plain IEC socket.

mnem
*Back out into the suck*

[mnementh]

2.5GHz thingie, not my fault, blame Berni. 

Don't take this the wrong way, but...

SCHWANNNGGGG!!! 


mnem
Morning wood is the BEST kind. 

[mnementh]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.

With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. 


mnem
But it is SUCH a slippery slope... 

[Specmaster]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.

With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. 


mnem
But it is SUCH a slippery slope... 

Excuse me while I grease your driveway  for you [emoji48]

From mobile device so predictive text might have struck again [emoji83]

[tggzzz]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.

With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. 

mnem
But it is SUCH a slippery slope... 

Excuse me while I grease your driveway  for you [emoji48]

The real pain with the 7081 is that it didn't have input connector and lead. Hence
https://www.eevblog.com/forum/testgear/the-unobtanium-connector-of-solartron-7061-what-to-do-please-help/msg1538429/#top
followed by
https://www.eevblog.com/forum/buysellwanted/group-buy-fischer-connector-plug-s104-a053-130/msg1538426/#msg1538426

As for my drive, it is quite steep enough (~10%) that algae is a sufficient grease

[Specmaster]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.

With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. 

mnem
But it is SUCH a slippery slope... 

Excuse me while I grease your driveway  for you [emoji48]

The real pain with the 7081 is that it didn't have input connector and lead. Hence
https://www.eevblog.com/forum/testgear/the-unobtanium-connector-of-solartron-7061-what-to-do-please-help/msg1538429/#top
followed by
https://www.eevblog.com/forum/buysellwanted/group-buy-fischer-connector-plug-s104-a053-130/msg1538426/#msg1538426

As for my drive, it is quite steep enough (~10%) that algae is a sufficient grease

Hmm algae and grease, you might as well give up then cos you're  a voltnut. 😂

[bd139]

When I see connectors and inlet provision like that Solartron, they get IEC-ized instantly!

....

Not really TEA but I have been suitably impressed today. Playing with some PIC10F320 microcontrollers. I think it is bloody amazing that you can get a whole damn computer in a SOT-23 package now. Literally all I'm using it for is generating two digital signals 180 degrees out of phase to drive inverter MOSFETs and enable/disable itself based on an ADC sample. This does however replace an entire 74hc14, regulator, a 2n3904, a trimmer and some external passives that were doing the job before with just itself, a tant and a much smaller regulator. Impressed

It's bloody tiny. That's a DIP / SOIC footprint board.



And yes I did lose the first one on the floor 

[Specmaster]

When I see connectors and inlet provision like that Solartron, they get IEC-ized instantly!

....

Not really TEA but I have been suitably impressed today. Playing with some PIC10F320 microcontrollers. I think it is bloody amazing that you can get a whole damn computer in a SOT-23 package now. Literally all I'm using it for is generating two digital signals 180 degrees out of phase to drive inverter MOSFETs and enable/disable itself based on an ADC sample. This does however replace an entire 74hc14, regulator, a 2n3904, a trimmer and some external passives that were doing the job before with just itself, a tant and a much smaller regulator. Impressed

It's bloody tiny. That's a DIP / SOIC footprint board.



And yes I did lose the first one on the floor 

Never mind the hoover will announce that it's found it when you do the hoovering, shame it'll bugger it as well though 🤣

From mobile device so predictive text might have struck again [emoji83]

[bd139]

I have a 5 year old. Henry is used to eating up much worse things

[tggzzz]

It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.

It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.

Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter

Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.

With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. 

mnem
But it is SUCH a slippery slope... 

Excuse me while I grease your driveway  for you [emoji48]

The real pain with the 7081 is that it didn't have input connector and lead. Hence
https://www.eevblog.com/forum/testgear/the-unobtanium-connector-of-solartron-7061-what-to-do-please-help/msg1538429/#top
followed by
https://www.eevblog.com/forum/buysellwanted/group-buy-fischer-connector-plug-s104-a053-130/msg1538426/#msg1538426

As for my drive, it is quite steep enough (~10%) that algae is a sufficient grease

Hmm algae and grease, you might as well give up then cos you're  a voltnut. 😂

... if I fall and hit my head, will anyone notice any difference

[Ero-Shan]

First things first.

When I came home the other day I spotted something behind the broom I keep in the corner of my entree staircase. Yes, it was a small parcel. And I hadn't ordered anything.
As it was correctly addressed to me, I entered my home and submitted to my curiosity. Out came a combined Volt, Ampere and power meter, as well as a nice box to house it.
The thing was exemplary packaged - it might have survived delivery by a cannon or being dropped by a SR71 flying Mach 3 at 80,000 ft.

Now I was the victim of a free giveaway! I won't tell who the donor was, but I'm sure as hell grateful to that person. You who must be commended knows who you are! Thanks very much!

Even though I currently abstain from TEA, I felt compelled to finish the box that will in the future be pressed into service when a DUT is powered up. Since plugging in and out those IEC plugs can be somewhat cumbersome, I added a switch that disconnects both lines. Initially, I wanted to put a mains socket into the box, but there was no way to fit one. So I went for a C13 outlet. This still meant that I had to use the housing upside down, but I don't care about that.

As this was a gift, I tried my utmost to make it as meticulous as I was able to (my mechanical work usually sucks big time). Here it is:



As mentioned above, I'm abstaining from TEA for some time. But I will follow this thread. Just not post much.

[Berni]

2.5GHz thingie, not my fault, blame Berni. 

Nice one. No need to thank me. This is what the TEA group is for.

But im sure you will enjoy the probe. I used my infiniium versions of them a lot and they run circles around any passive probe for high speed digital use.

[Specmaster]

First things first.

When I came home the other day I spotted something behind the broom I keep in the corner of my entree staircase. Yes, it was a small parcel. And I hadn't ordered anything.
As it was correctly addressed to me, I entered my home and submitted to my curiosity. Out came a combined Volt, Ampere and power meter, as well as a nice box to house it.
The thing was exemplary packaged - it might have survived delivery by a cannon or being dropped by a SR71 flying Mach 3 at 80,000 ft.

Now I was the victim of a free giveaway! I won't tell who the donor was, but I'm sure as hell grateful to that person. You who must be commended knows who you are! Thanks very much!

Even though I currently abstain from TEA, I felt compelled to finish the box that will in the future be pressed into service when a DUT is powered up. Since plugging in and out those IEC plugs can be somewhat cumbersome, I added a switch that disconnects both lines. Initially, I wanted to put a mains socket into the box, but there was no way to fit one. So I went for a C13 outlet. This still meant that I had to use the housing upside down, but I don't care about that.

As this was a gift, I tried my utmost to make it as meticulous as I was able to (my mechanical work usually sucks big time). Here it is:



As mentioned above, I'm abstaining from TEA for some time. But I will follow this thread. Just not post much.

Wow you were lucky then, it looks like mine but only far far better carried out and your mechanical work certainly does not suck, that looks very professional, so much so that I may have to rethink mine and do something similar with it.

Hmm are you by any chance a lefty?

So damn you and your unknown benefactor, now I'm going to have to revisit my one now and do some revamping of it, I like the idea of the power switch although mine only has a short lead that plugs directly into my variac which its own power switch, damn it.

As to the packaging I must say thats its very comforting to learn that there is someone who understands how to pack things regardless of the means of delivery, all to often we hear of horror stories of packaging disasters.

 

 

[BravoV]

2.5GHz thingie, not my fault, blame Berni. 

Nice one. No need to thank me. This is what the TEA group is for.

But im sure you will enjoy the probe. I used my infiniium versions of them a lot and they run circles around any passive probe for high speed digital use.

I'm quite surprised that the probe's body is heavy, if connected directly and hanging horizontally, perpendicular with the equipment front panel, worry that the stress caused by it's weight will wreck the N terminal at the spectrum analyzer or at the scope's BNC terminal using the included N to BNC adapter.

Thinking of using a L shape adapter, to make the probe body parallel with the equipment front panel, and I guess this should help to relieve the stress by resting part of the body weight on the bench surface, rather than hanging horizontally, how do you use yours ? Or I'm worry too much ?

[mnementh]

Hmm algae and grease, you might as well give up then cos you're  a voltnut.   

... if I fall and hit my head, will anyone notice any difference

Depends... How big a dent you think you'll make?   


mnem
*Hanging onto my sanity by a thread*

[tautech]

When I see connectors and inlet provision like that Solartron, they get IEC-ized instantly!

....

Not really TEA but I have been suitably impressed today. Playing with some PIC10F320 microcontrollers. I think it is bloody amazing that you can get a whole damn computer in a SOT-23 package now. Literally all I'm using it for is generating two digital signals 180 degrees out of phase to drive inverter MOSFETs and enable/disable itself based on an ADC sample. This does however replace an entire 74hc14, regulator, a 2n3904, a trimmer and some external passives that were doing the job before with just itself, a tant and a much smaller regulator. Impressed

It's bloody tiny. That's a DIP / SOIC footprint board.



And yes I did lose the first one on the floor 

SOT23-6, real fun to route a board for when you need to get power traces from each side into the middle pin.
Soldering is not as hard. 

I use a little dual complementary MOSFET as a driver and they're great fun to work with.

[bd139]

I notice they solved that on some devices like opamps by having variants with different pin outs. Soldering SMD stuff is really easy. Easier than TH when you get the hang of it. Quite enjoying it.

Now you’ve got me looking for MOSFETs. I’m using two larger IRF510’s at the moment but something much smaller will work. Might even kick the frequency up a bit and use a smaller transformer.

[tautech]

I notice they solved that on some devices like opamps by having variants with different pin outs. Soldering SMD stuff is really easy. Easier than TH when you get the hang of it. Quite enjoying it.

Now you’ve got me looking for MOSFETs. I’m using two larger IRF510’s at the moment but something much smaller will work. Might even kick the frequency up a bit and use a smaller transformer.

I don't drive these fast at HF mainly just for a capable buffer from logic to power devices that aren't available with logic level inputs. Some reckon I'm doing it wrong and will suffer shoot though issues but I've not seen any and I think I have good enough gear to find it if it was there. Just be mindful of it. 

Edited above for clarity.
Gate rise times are still quick.

There might be better ones available now but I've stocked up a while back ...........

[bd139]

Certainly match my requirements. Will have a look around at similar ones as well. Thanks for the recommendation. I haven’t even looked at the new MOSFETs yet properly. I’m still in ancient 2n7000 and IRF510 territory.

Sounds reasonable to me. I think shoot through was what was causing my RF PA to sling bits of MOSFETs in my general direction. I increased the gate drive and it went away. I couldn’t capture this event on the tek 465 unfortunately. Bit easier on a digital scope as it only happens a few times before smoke comes out.

[Specmaster]

Certainly match my requirements. Will have a look around at similar ones as well. Thanks for the recommendation. I haven’t even looked at the new MOSFETs yet properly. I’m still in ancient 2n7000 and IRF510 territory.

Sounds reasonable to me. I think shoot through was what was causing my RF PA to sling bits of MOSFETs in my general direction. I increased the gate drive and it went away. I couldn’t capture this event on the tek 465 unfortunately. Bit easier on a digital scope as it only happens a few times before smoke comes out.

Hmm, I think you just made a perfectly good argument for having both a analogue and a digital scope in you tool kit right there apart from the other things that a digital scope can do that an analogue can't do. Even if it doesn't get used that much, if you can afford it then I'd say have both. I know that I'd like to have both if only I could afford both, perhaps one day I will be able to as the price drops.

[tautech]

Certainly match my requirements. Will have a look around at similar ones as well. Thanks for the recommendation. I haven’t even looked at the new MOSFETs yet properly. I’m still in ancient 2n7000 and IRF510 territory.

Sounds reasonable to me. I think shoot through was what was causing my RF PA to sling bits of MOSFETs in my general direction. I increased the gate drive and it went away. I couldn’t capture this event on the tek 465 unfortunately. Bit easier on a digital scope as it only happens a few times before smoke comes out.

Hmm, I think you just made a perfectly good argument for having both a analogue and a digital scope in you tool kit right there apart from the other things that a digital scope can do that an analogue can't do. Even if it doesn't get used that much, if you can afford it then I'd say have both. I know that I'd like to have both if only I could afford both, perhaps one day I will be able to as the price drops.

Accurate confirmation of shoot through is possible with a CRO if the FET switching is repetitive.
A good current probe makes this fairly easy to see.

Yesterdays find while searching for an hour to find a part I put down a few yards from the bench instead of on the bloody bench ! 
Bench and surrounds are now half cleaned in the search and the prize was another Tek P6021 current probe head that I'd forgotten I owned. 
That makes 3.........yes 3, I'm afflicted by P6021 TEA !
Just needing another termination for it now. 

[bd139]

Certainly match my requirements. Will have a look around at similar ones as well. Thanks for the recommendation. I haven’t even looked at the new MOSFETs yet properly. I’m still in ancient 2n7000 and IRF510 territory.

Sounds reasonable to me. I think shoot through was what was causing my RF PA to sling bits of MOSFETs in my general direction. I increased the gate drive and it went away. I couldn’t capture this event on the tek 465 unfortunately. Bit easier on a digital scope as it only happens a few times before smoke comes out.

Hmm, I think you just made a perfectly good argument for having both a analogue and a digital scope in you tool kit right there apart from the other things that a digital scope can do that an analogue can't do. Even if it doesn't get used that much, if you can afford it then I'd say have both. I know that I'd like to have both if only I could afford both, perhaps one day I will be able to as the price drops.

Honestly if I had to have one scope or worked in a professional environment I’d use only a digital scope at this point. One with a decent memory depth. The ability to catch glitches and rare events is incredibly valuable.

I have been quite frustrated debugging a few problems recently which did motivate the purchase of the digital scope. Even this evening I was arguing with PIC WDT.

[tautech]

Certainly match my requirements. Will have a look around at similar ones as well. Thanks for the recommendation. I haven’t even looked at the new MOSFETs yet properly. I’m still in ancient 2n7000 and IRF510 territory.

Sounds reasonable to me. I think shoot through was what was causing my RF PA to sling bits of MOSFETs in my general direction. I increased the gate drive and it went away. I couldn’t capture this event on the tek 465 unfortunately. Bit easier on a digital scope as it only happens a few times before smoke comes out.

Hmm, I think you just made a perfectly good argument for having both a analogue and a digital scope in you tool kit right there apart from the other things that a digital scope can do that an analogue can't do. Even if it doesn't get used that much, if you can afford it then I'd say have both. I know that I'd like to have both if only I could afford both, perhaps one day I will be able to as the price drops.

Honestly if I had to have one scope or worked in a professional environment I’d use only a digital scope at this point. One with a decent memory depth. The ability to catch glitches and rare events is incredibly valuable.

You don't need lots of memory, sampling rate, colored intensity grading and a good trigger suite are the key helpers in finding glitches and rare events.