Test Equipment Anonymous (TEA) group therapy thread

[bd139]

I remember that X files. Yeah that was a risk 

Had big yellow sticker on the wall: DO NOT STAND IN FRONT OF THE HORN OR LOOK INTO THE APERTURE. The aforementioned horn was farting out its deadly spew into a big foam lined metal box that made a pretty horrid smell after a couple of minutes, sort of like that weird smell you get when you try and burn Ikea furniture. If you looked at it for a few seconds, bye bye sight or poppity ping goes your eyeball. One of my colleagues got a nice red square on his arm after doing something stupid. It was only a few tens of watts as well.

Had three kids since then so didn't do any damage which removed my genes from the pool by the looks.

[Specmaster]

And I thought that virtual reality was a new thing, turns out not to be and also smell vision has also has been available 

[mnementh]

Well, that's more like "altered reality vision"; you can see infinity, feel the void, smell the number 9, or even taste the colour purple and count water when you're brain's being cooked from the inside. 


mnem
What you hear is none of my damn business. 

[bd139]

Got me another project for when everything has calmed down. Broken HP 6237B power supply.

[Specmaster]

Nice and with analogue meters, but the voltage adjustment is a bit on the course side, will you be fitting multi turn pots?

[bd139]

I’ll probably leave it be. They are tetchy as fuck. It’ll run my QRP transceiver off the first channel and leave two channels and two TTi supplies free for development work. I am forever running out of power supplies.

Plus I had a 6236B years ago and I miss it.

[Specmaster]

juat watched a video of a 6237B and it was clear how touchy those controls are in it.

I'm just stripping down a 2TB sky+ box to get the drive out of it.

[tautech]

Nice and with analogue meters, but the voltage adjustment is a bit on the course side, will you be fitting multi turn pots?

I’ll probably leave it be. They are tetchy as fuck. It’ll run my QRP transceiver off the first channel and leave two channels and two TTi supplies free for development work. I am forever running out of power supplies.

Plus I had a 6236B years ago and I miss it.

A linear PSU I built years back I put a 10t Bournes in it but it's a bit of a PITA when you shift voltage from one job to another however a little SMPS I have has 5t pots and they're much more convenient to use while still offering adequate resolution.
My 2c worth.

[Specmaster]

Nice and with analogue meters, but the voltage adjustment is a bit on the course side, will you be fitting multi turn pots?

I’ll probably leave it be. They are tetchy as fuck. It’ll run my QRP transceiver off the first channel and leave two channels and two TTi supplies free for development work. I am forever running out of power supplies.

Plus I had a 6236B years ago and I miss it.

A linear PSU I built years back I put a 10t Bournes in it but it's a bit of a PITA when you shift voltage from one job to another however a little SMPS I have has 5t pots and they're much more convenient to use while still offering adequate resolution.
My 2c worth.

Always appreciated.

[bd139]

My TTi supplies have course and fine adjust plus the current pot is a log one. Really the best option IMHO on an analogue supply other than digital setting it via encoder/digital.

I use a 10 turn on a QRP rig I built for VFO. Gives 2Khz tuning per turn. Bloody pot cost more than the rest of the transceiver cost.

@specmaster: good job on the sky boxes.  Best thing about them 

Edit: correct kHz/turn.

[Specmaster]

Yep, they are a good source of cheap drives, especially if you can get them for free or very little.

Edit, stick them in an enclosure and you have cheap backup drive

[tautech]

My TTi supplies have course and fine adjust plus the current pot is a log one. Really the best option IMHO on an analogue supply other than digital setting it via encoder/digital.

Nah, course and fine pots are the cheap way out and nothing more. 
Never liked that setup at all and refused to stock anything with them.
Right PITA compared to a 10t pot with a good heavy knob that does a few turns when you give it a flick.

Bloody pot cost more than the rest of the transceiver cost.

Sure buying 1x but for manufactures that but them buy 1k, 10k or 100k how much will it really add to the retail cost of a PSU ? Bugger all and provides a nicer cleaner layout.

This is why digital setting has taken off .......cost and better preciseness......but I'm amused you prefer dual pots to 10t or digital but it all depends on how digital is implemented. Encoder only, numeric keypad, up/down buttons or some combination of any/all of them. HW costs of digital has to be cheapest but how it's implemented is the key to usability.

[bd139]

People like ‘em.  The newer TTi supplies actually have digital setting and course / fine controls. Literally fastest setting time other than entering the value on a keypad.

Definitely a PITA compared to a 10t with lots of momentum. However if you look at those and I have seen one one some test gear years ago is some chumpty always comes along and ends up killing the end stop in two minutes flat by spinning it to the end.

Decent digital costs serious money. The optical encoder on my Yaesu rig costs £55 a go. If you have to have precise input the “select digit and change” method is just vile. Encoder + keypad are a nice combo.

BUT and this is a big one, how often do you need a really accurate voltage? Within 5% or so is most of electronics. I don’t set my rails to 15.00 and -15.00 volts. Usually one comes up around 14V and the other 15.5. Logic is happy 500mV either way usually. The first receiver I built had 5% components throughout and took a 8-20V supply and was still frequency stable to 20Hz/min drift.

[tautech]

People like ‘em.  The newer TTi supplies actually have digital setting and course / fine controls. Literally fastest setting time other than entering the value on a keypad.

Definitely a PITA compared to a 10t with lots of momentum. However if you look at those and I have seen one one some test gear years ago is some chumpty always comes along and ends up killing the end stop in two minutes flat by spinning it to the end.

Decent digital costs serious money. The optical encoder on my Yaesu rig costs £55 a go. If you have to have precise input the “select digit and change” method is just vile. Encoder + keypad are a nice combo.

BUT and this is a big one, how often do you need a really accurate voltage? Within 5% or so is most of electronics. I don’t set my rails to 15.00 and -15.00 volts. Usually one comes up around 14V and the other 15.5. Logic is happy 500mV either way usually. The first receiver I built had 5% components throughout and took a 8-20V supply and was still frequency stable to 20Hz/min drift.

Yep, rarely and just the point I made a few posts back WRT 5t pots.

However modern digital PSU's have some decent acceleration logarithms acting on the encoder so are pretty decent to use compared to step by step increments. Others have memory that you set for your commonly used values and jump to them with a couple of key presses.

[tggzzz]

BUT and this is a big one, how often do you need a really accurate voltage?

If you are doing linearity testing, it can be convenient to step in accurate increments. Ditto sensisitity testing.

[bd139]

Fair point. But.... When I was designing the VCO for my SA, which is a varactor controlled colpitts oscillator I used my old Farnell supply set to a random voltage with a 2k 10 turn pot nicked from a parts mule scope across it and a DMM to set it. YMMV of course. Note that the pot was buffered by a simple follower.

[Miti]

When I go to the test equipment folder I see: EEVblog Electronics Community Forum » Products » Test Equipment and the buttons are where they should be.

Where do you end up when clicking this: https://www.eevblog.com/forum/testgear/ ?

I get where I want to get. I just don't understand why I don't end up in the same page when I click Home > Test Equipment. Anyway, it's all good now, crisis averted.

[capt bullshot]

However modern digital PSU's have some decent acceleration logarithms acting on the encoder so are pretty decent to use compared to step by step increments. Others have memory that you set for your commonly used values and jump to them with a couple of key presses.

IMO the acceleration is fucking up the usability. Having keys to select the digit, and then doing steps by the encoder is OK since you can select the resolution that way. The encoder of a HPAK 33120 or the more modern 33522 Generator works that way, and I find it quite useful. The encoder of the HPAK 36312 power supply is not useful for me. It always steps the least significant digit and accelerates if you turn if faster - you don't have any control over the resolution. A 10 turn pot is still the best way for me, since it gives you decent resolution and you've got all the control within your fingers in a predictable way. Accelerating encoders are quite inpredictable for my human intuition. Even with the CMU200's encoder, which is high qualtity and gives a pretty good feedback when operating it.

[bd139]

Yes. I don’t think I could handle accelerating encoders. That’s mr clippy style helpful. At best digit select and encoder. That allows you to sweep each place value.

This is where the course / fine control comes in. Gives you 100:1 range easily and reproducibly. You learn where the knob is rather than having to do a linear search each time. Not suitable for all situations but for voltage selection it works pretty well.

[tautech]

However modern digital PSU's have some decent acceleration logarithms acting on the encoder so are pretty decent to use compared to step by step increments. Others have memory that you set for your commonly used values and jump to them with a couple of key presses.

IMO the acceleration is fucking up the usability. Having keys to select the digit, and then doing steps by the encoder is OK since you can select the resolution that way. The encoder of a HPAK 33120 or the more modern 33522 Generator works that way, and I find it quite useful. The encoder of the HPAK 36312 power supply is not useful for me. It always steps the least significant digit and accelerates if you turn if faster - you don't have any control over the resolution. A 10 turn pot is still the best way for me, since it gives you decent resolution and you've got all the control within your fingers in a predictable way. Accelerating encoders are quite inpredictable for my human intuition. Even with the CMU200's encoder, which is high qualtity and gives a pretty good feedback when operating it.

Do you have the means to select just which digit to adjust with the encoder and then that digit is highlighted while selected ?

[Specmaster]

General Heads Up for all UK based TEA members, if you're looking for a TEK 465 with the digital meter module there's one coming up this Friday (14th) in an auction  , details of which are here https://www2.ppauctions.com/auction.php?id=229 which is located in Norwich. Its a TV studio called Epic TV thats being closed down I think.

[Specmaster]

OFF TOPIC

General request for any members the UK, living near Sheffield and Merthyr Tydfil who would be willing to collect something from sellers who will not post, and then post them onto to me, all expenses covered plus a bit extra, please PM me to discuss details. thanking you in advance.

[bd139]

*looks at diary*. Nearest place is brum next Friday

My monitor has just blown up. RIP. Looks like power supply has gone phut properly. Has been repaired once already so going to sling this one I think now.

[Specmaster]

Whats the make of monitor?

[Mr. Scram]

Whats the make of monitor?

PENI - Sfingers edition.