Test Equipment Anonymous (TEA) group therapy thread

[Zucca]

Meanwhile...

I believe that the package shipping circus in this Nov-Dec 2020 will be a monumentally colossal shit show.
Organize/conclude your TEA shipping this week or pospone everything after XMas.

I warned you.

[med6753]

Meanwhile...

I believe that the package shipping circus in this Nov-Dec 2020 will be a monumentally colossal shit show.
Organize/conclude your TEA shipping this week or pospone everything after XMas.

I warned you.

I suspect the shipping services are already anticipating a record on line ordering this holiday season due to the pandemic. My take is that UPS and FedEx will handle it. USPS on the other hand will choke. I'll bet Royal Mail will choke too.

[bd139]

RM does pretty well during xmas period. They've even started offering a consumer collection service now. They have assured delivery times up until 23rd of December too. You can post something on 23rd and it WILL arrive on the 24th if you pay for it.

Christmas is mostly coming via Amazon Logistics here though 

[med6753]

More free groceries? 

[bd139]

I'm still tempted to have another go. If it fucks up profitably every time then the inconvenience is worth it 

[tautech]

 
End of day Devils Cut and there's no Coke or dry ginger ale in the house ! 

Need a new house keeper..............

[med6753]

When I was in Staten Island on Sunday I saw numerous Amazon vans cruising around making deliveries. I wish they had that up here although USPS does do a fair job of making Sunday deliveries, but only on Amazon packages. If you have a package from other than Amazon it's FU wait until normal delivery on Monday.

[med6753]

End of day Devils Cut and there's no Coke or dry ginger ale in the house ! 

Need a new house keeper..............

Her one job and she failed at it. I dare you to tell her that. 

Do you have a dog house? 

[Specmaster]

More free groceries? 

You beat me to that one 

[tautech]

End of day Devils Cut and there's no Coke or dry ginger ale in the house ! 

Need a new house keeper..............

Her one job and she failed at it. I dare you to tell her that. 

Do you have a dog house? 

I do, actually a 3 kennel/run dog motel !
All insulated floors, walls and ceiling  but the spare room still looks more attractive ! 

[Specmaster]

End of day Devils Cut and there's no Coke or dry ginger ale in the house ! 

Need a new house keeper..............

Her one job and she failed at it. I dare you to tell her that. 

Do you have a dog house? 

If not, better start building one NOW

[mansaxel]

Edit: Still south of the Mason-Dixon line, but it's out of Texas, in TN now.

Memphis, TN is the main UPS hub for all air shipping, both domestic and world wide. Your package should go direct from that location.

Yabbut this is FedEx. However, FedEx lives in Memphis. UPS, OTOH, is hubbed in Louisville, KY. Also south of the line, though.

[mansaxel]

RM does pretty well during xmas period. They've even started offering a consumer collection service now. They have assured delivery times up until 23rd of December too. You can post something on 23rd and it WILL arrive on the 24th if you pay for it.

Christmas is mostly coming via Amazon Logistics here though 

I've also started.  Christmas calendars for the children (via Postnord), christmas calendar for wife (via DHL) and some smaller gifts for christmas eve, via Postnord. Made certain I did mention calendars for the children to the wife so she'll make sure to order one for me too ;-)

[med6753]

Edit: Still south of the Mason-Dixon line, but it's out of Texas, in TN now.

Memphis, TN is the main UPS hub for all air shipping, both domestic and world wide. Your package should go direct from that location.

Yabbut this is FedEx. However, FedEx lives in Memphis. UPS, OTOH, is hubbed in Louisville, KY. Also south of the line, though.

Oops, you're right. I got the two confused.

[Robert763]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

If you want high voltage look at the "Royer" type inverters that were used for CCFL back lights. The simple two transistor ones. With a fullwave rectifier (fast diodes and ditch the series "ballast" capacitor) they have a remarkably linear input-output voltage transfer characteristic. This is particuarly true if you under-run them. I've used the 12V input ones used by PC case modders with up to 8V in with good results Might need a it of a fixed load, but a voltage divider would do that and get your minimum voltage down a bit too.
Using one as a tracking pre-regulator for a floating regulator like a LM317 works well too.
I first used them for PMT supples with a feedback loop but quickly realised they were linear enough not too need it. I just stuck a LM317 with a 10 turn pot on the input and they were fine.
John Williams wrote some app notes on CCFL powersupplies that are well worth looking at. He also wrote about HV nd linearity measurements.   

[dl6lr]

"Whats all this flux stuff, anyhow?" 

Bernd

[bd139]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

If you want high voltage look at the "Royer" type inverters that were used for CCFL back lights. The simple two transistor ones. With a fullwave rectifier (fast diodes and ditch the series "ballast" capacitor) they have a remarkably linear input-output voltage transfer characteristic. This is particuarly true if you under-run them. I've used the 12V input ones used by PC case modders with up to 8V in with good results Might need a it of a fixed load, but a voltage divider would do that and get your minimum voltage down a bit too.
Using one as a tracking pre-regulator for a floating regulator like a LM317 works well too.
I first used them for PMT supples with a feedback loop but quickly realised they were linear enough not too need it. I just stuck a LM317 with a 10 turn pot on the input and they were fine.
John Williams wrote some app notes on CCFL powersupplies that are well worth looking at. He also wrote about HV nd linearity measurements.

Yeah I've got the high voltage generation sorted. That's not an issue. I'm using a flyback converter for that with a voltage comparator to set the max voltage. The problem I have is sweeping the voltage up and down at around 50Hz across the full compliance range. I think I have a solution. The phase shift is coming from the excessive miller capacitance of the pass transistor.

Anyway today's task is writing a Gopher client in Go. Why? Why the fuck not. Mostly working already!

[mnementh]

"Whats all this flux stuff, anyhow?" 

Bernd

That's where the last surviving lab tech at B&K soldered in the chips to make a BNC 625 mainboard into a BNC 625A mainboard with ARB functions. 

mnem
May Ifni grant his poor broken soul peace at last...

[mnementh]

...Anyway today's task is writing a Gopher client in Go. Why? Why the fuck not.

Because your testicles have been tenderized enough this week already, and you want to save some misery for later on the off-chance you might run out...?

mnem
"There's enough misery to go around without grabbing for more." ~mom

[25 CPS]

I bought this one on sale for 150$Can. Frame is solid steel and the top hardwood. It's great. With the 5inch wheels you can move it around easily.

I would not trust putting the 519 on that type of cart. Not because of the weight but because of the height it could present a tipping hazard. My cart at it's highest point is only 25 inches above the floor. Low center of gravity even with the 535A on it. And it's stable with no tendency to tip when moved around.

That cart's actually quite large so the four wheels and legs are far enough apart it's not a tipping hazard with heavy objects on top.  Taking chunks out of things with the corners, that's another matter altogether.

[tggzzz]

So, will it or won't it survive?

I picked up a Telequipment DM63 scope with four five six nice features:

• analogue storage
• three channels
• dual beam - so none of this chop/alt to screw up capturing two fast one-off events
• a price I couldn't resist
• manuals - now uploaded to ko4bb
• extender card

After recapping it works very nicely. Single-sided boards and big holes make that relatively easy.

Here's the stored trace when I manually switch my hp3310a from triangle to sine to square wave during the sweep:



But mechanically it leaves a bit to be desired. It weighs 15kg, "most" of in the mains transformer. That wouldn't be a problem, but the way the PSU is secured seems very "cost effective" The transformer is mounted on the backplate of a plugin. The plugin is supported by the PCB connector on one side (bottom) and the backplate on the other:



The backplate is clamped to the frame by two relatively small bolts (holes visible on the sides):



And the PCB connector is mounted on the "motherboard":




So, mesdames et messieurs, place your bets: would it survive shipping?

[tautech]

So, will it or won't it survive?

I picked up a Telequipment DM63 scope with four nice features:

• analogue storage
• three channels
• dual beam - so none of this chop/alt to screw up capturing two fast one-off events
• a price I couldn't resist

After recapping it works very nicely. Single-sided boards and big holes make that relatively easy.

Here's the stored trace when I manually switch my hp3310a from triangle to sine to square wave during the sweep:



But mechanically it leaves a bit to be desired. It weighs 15kg, "most" of in the mains transformer. That wouldn't be a problem, but the way the PSU is secured seems very "cost effective" The transformer is mounted on the backplate of a plugin. The plugin is supported by the PCB connector on one side (bottom) and the backplate on the other:



The backplate is clamped to the frame by two relatively small bolts (holes visible on the sides):



And the PCB connector is mounted on the "motherboard":




So, mesdames et messieurs, place your bets: would it survive shipping?

Nice tidy example tggzzz ! 

Brings a tear to the eye of a previous D83 owner.

[tggzzz]

Nice tidy example tggzzz ! 

Brings a tear to the eye of a previous D83 owner.

I've added another couple of goodies: manuals (now scanned and uploaded to ko4bb) and extender card

[nfmax]

Nice tidy example tggzzz ! 

Brings a tear to the eye of a previous D83 owner.

I've added another couple of goodies: manuals (now scanned and uploaded to ko4bb) and extender card

I've got a DM63 as well, in the storage cupboard. It certainly is heavy. Last time I turned it on, it worked in variable persistence mode OK but true storage was long gone. I wonder if it still works?

[BU508A]

Yeah I've got the high voltage generation sorted. That's not an issue. I'm using a flyback converter for that with a voltage comparator to set the max voltage. The problem I have is sweeping the voltage up and down at around 50Hz across the full compliance range. I think I have a solution. The phase shift is coming from the excessive miller capacitance of the pass transistor.

What pass transistor is it? BU508A?