Test Equipment Anonymous (TEA) group therapy thread

[bd139]

With power supplies you get what you pay for. This is why I buy old ones. You get what someone else paid for at the same price as you pay for a cranky house incinerator.

As mentioned earlier, inflation adjusted, a 6205B would have been around £1595 in current times as an example. That's probably why they pulled that line and went to plastic fantastic E36xx series which was mostly about economy.

[Specmaster]

These PL series supplies certainly have had many design changes over the years internally more than external, I have this PL310 which only uses a single 2N3055 pass transistor, and yet I have a older PL320 that has 4 of them and a newer TS3021S that has 3, the latter, although having a different model prefix, is essentially a PL with LCDs in place of LEDs.

[nfmax]

These PL series supplies certainly have had many design changes over the years internally more than external, I have this PL310 which only uses a single 2N3055 pass transistor, and yet I have a older PL320 that has 4 of them and a newer TS3021S that has 3, the latter, although having a different model prefix, is essentially a PL with LCDs in place of LEDs.

More perhaps than almost any other device, the 2N3055 has, over the years, been a moveable feast in terms of its performance. I suspect the design was changed to suit the parts they could buy at the time.

[Saskia]

Another haul.
Shitloads of stuff. Raaco carousel 45€, 4 TB 2.5". HArd drive, 24" LG ips business monitor (50 pesos), some industrial ddr4 so dimm ,(ext. Temperature range -80 centigrade) plus some stuff I can use to build my own ac independent soldering iron ...

[Specmaster]

These PL series supplies certainly have had many design changes over the years internally more than external, I have this PL310 which only uses a single 2N3055 pass transistor, and yet I have a older PL320 that has 4 of them and a newer TS3021S that has 3, the latter, although having a different model prefix, is essentially a PL with LCDs in place of LEDs.

More perhaps than almost any other device, the 2N3055 has, over the years, been a moveable feast in terms of its performance. I suspect the design was changed to suit the parts they could buy at the time.

Why should that be, it must have hit certain parameters to be called a 2N3055, anything else just would not be a 2N3055 surely?

[bd139]

2N3055 transistors vary considerably on all parameters. All the specifications are "aspirational" at best. You occasionally can't use new 2n3055's in old devices without a capacitor added across base-collector to slow 'em down.

[nfmax]

2N3055 transistors vary considerably on all parameters. All the specifications are "aspirational" at best. You occasionally can't use new 2n3055's in old devices without a capacitor added across base-collector to slow 'em down.

Hit that one once with mica TO3 insulating washers. Over time, they got thinner, and the increased capacitance caused us problems!

[mnementh]

I wish there was a "never show me shit by that idiot again" button on ebay. That'd clear up those items nicely

When you have done a search, under "show only", See more", "seller" there is an option to exclude a list of sellers.
Also available under advanced search.

Yeah but you have to explicitly use it every time. We have before bemoaned the fact that you can't blacklist sellers (from your private point of view) on a permanent basis.

Yeah; they've had the built-in advertising Favorites "feature"  since the dawn of time, so the database is already there. All we'd need is a nice little "Fuck off & Die" button added to it.

OTOH, I've been feeling that way in general aboot fleaBay for a while now... so... 

mnem

[bd139]

2N3055 transistors vary considerably on all parameters. All the specifications are "aspirational" at best. You occasionally can't use new 2n3055's in old devices without a capacitor added across base-collector to slow 'em down.

Hit that one once with mica TO3 insulating washers. Over time, they got thinner, and the increased capacitance caused us problems!

Yeah can see that being a problem! Reminds me of an interesting design I saw here: https://ludens.cl/Electron/Ps20/Ps20.html

The collectors of the 2N3055's are grounded thus leading to less issues, better thermal conductivity and one less headache

[mnementh]

Oklay... where do you get one, and how much? Everyplace I go says they're NLA. 

I can only assume the company went busted after the Kickstarter. This makes my unit even more "gold plated".

Well, a very cordial "Fuck you!" to you then as well! 

mnem

[BravoV]

Got seduced by TON (Temptations Of NOS). 

Hint ... European made, an ancient relic, very pristine condition, clue ... the "bakelite" is still so shiny. 

Wish me luck, will update if I scored it, still in the heat of bargaining. 

[med6753]

Got seduced by TON (Temptations Of NOS). 

Hint ... European made, an ancient relic, very pristine condition, clue ... the "bakelite" is still so shiny. 

Wish me luck, will update if I scored it, still in the heat of bargaining. 

The smell of burning bakelite brings back fond memories of my youth. 

[mnementh]

These PL series supplies certainly have had many design changes over the years internally more than external, I have this PL310 which only uses a single 2N3055 pass transistor, and yet I have a older PL320 that has 4 of them and a newer TS3021S that has 3, the latter, although having a different model prefix, is essentially a PL with LCDs in place of LEDs.

More perhaps than almost any other device, the 2N3055 has, over the years, been a moveable feast in terms of its performance. I suspect the design was changed to suit the parts they could buy at the time.

Why should that be, it must have hit certain parameters to be called a 2N3055, anything else just would not be a 2N3055 surely?

I've attached some of my personal collection of various "2N3055 decapped" pics so you can see how they've changed since the original by RCA back in the stone age.

The 2N3055 is a victim of its own success; you really can't even call most of the newer ones "fakes" as the originators of the part have made so many "variants" during the transition from the original homeotaxial design to epitaxial production, that you need a scorecard (a good one is at the bottom of this page: https://en.wikipedia.org/wiki/2N3055 ) just to keep track. Once these chips are out there in the wild as an "equivalent", every manufacturer and his grandmomma gonna put it in whatever package they damn well feel like.

   

OTOH, that fact can make a designer stop a minute and make a circuit with some latitude in parts selection.

This old bruiser of a PSU is a case in point; it came with 5 2N3055 pass transistors in parallel, driven by a 2N2955. I've rebuilt it a dozen times, as the "short-circuit protection" is a joke and one or more of the pass transistors always takes the hit. BUT... once voltage is set, it'll happily sit right where you set it, drifting less than 100mV for weeks. Not bad for all-analog LM723-based design with a couple dozen parts ahead of the pass elements. That I got for scrap weight because someone shorted it out. 

Point being... I've rebuilt this thing with 2SD1049s, 2N3055s (sometimes mixed) and even some TTC5200s left over from my amp rebuilding daze. In fact, IIRC it's got a TTA1943 as the complimentary driver right now, and I think there was a while when finals was just 2 huge honkin' MJ-something-something in a TO247 package; it didn't care.

mnem
tzzzzt.

[mnementh]

Got seduced by TON (Temptations Of NOS). 

Hint ... European made, an ancient relic, very pristine condition, clue ... the "bakelite" is still so shiny. 

Wish me luck, will update if I scored it, still in the heat of bargaining. 

Another AVO? A Crosley Radio? The Desk Lamp of Doom? 

mnem
 

[bd139]

That thing is fucking ugly 

Been after one of these for years: https://en.wikipedia.org/wiki/Tizio

[BU508A]

If one is interested in some hi-res pictures and an in-depth analysis of semiconductors, then Richis Lab is a very good address. Highly recommended from my side. 
Warning! If you are susceptible for procrastination, this website is very dangerous for you!   

And as for the 2N3055: here one can find a lot of different examples and an analysis from Richi.

Example: RCA from 1973 (hometaxial)



Here one can see the pn-junction glowing. Isn't that gorgeous? 

[tggzzz]

That thing is fucking ugly 

Been after one of these for years: https://en.wikipedia.org/wiki/Tizio

Almost bought one of those 35 years ago!

I do have a luminaire and an ashtray by Artemide. The latter is a bloody strupid design for an ashtray, and my daughter hated it until I showed her the auction price

[BravoV]

Got seduced by TON (Temptations Of NOS). 

Hint ... European made, an ancient relic, very pristine condition, clue ... the "bakelite" is still so shiny. 

Wish me luck, will update if I scored it, still in the heat of bargaining. 

Another AVO? A Crosley Radio? The Desk Lamp of Doom? 

mnem
 

Ewww ... not that lamp, yuckkk !!! 

Well, more clues ... it was made pre-WW2 era in Nuremberg (I guess), and that rules out AVO as its Brit, but I guess I will just keep the thrill. 

Promise, if scored, I will post the complete photoshots & teardown, wish me luck.

[mnementh]

...The Desk Lamp of Doom? 

mnem
 

That thing is fucking ugly 

   Been after one of these for years: https://en.wikipedia.org/wiki/Tizio

What would you expect of the DLoD...? Luxo style?



I have one of the original Luxo Balanz desk lamps in storage; this pic is a clone. And of course, I chronicled the restoration of my Luxo Terea here in this thread a year ago or so:





I recently acquired a Ikea Riggad for my bedside; not quite as timeless a look as the Luxos, but all metal construction and I like the natural wood accents for the bedroom. Plus, excellent reading flood dispersal with absolutely zero bright spots or halo and 10W Qi-charging/USB.

mnem
*lit AF*

[Wolfgang]

2N3055 transistors vary considerably on all parameters. All the specifications are "aspirational" at best. You occasionally can't use new 2n3055's in old devices without a capacitor added across base-collector to slow 'em down.

Hit that one once with mica TO3 insulating washers. Over time, they got thinner, and the increased capacitance caused us problems!

Yeah can see that being a problem! Reminds me of an interesting design I saw here: https://ludens.cl/Electron/Ps20/Ps20.html

The collectors of the 2N3055's are grounded thus leading to less issues, better thermal conductivity and one less headache

A caveat:
The circuit in the link has two disadvantages:
- No compensation cap and resistor
- 5A per transistor is a bit much. In case of a short circuit, total dissipation is several 100W, on just 4 transistors.
  Fan and temp protection is needed, IMHO

[nfmax]

We're engineers, right?

This is the really important stuff about desk lighting: https://eprints.lancs.ac.uk/id/eprint/20295/1/20295.pdf

[bd139]

On desk lamps, I have one of these which I thoroughly recommend:

https://www.amazon.co.uk/dp/B01M7YLKQ3/

Also RF silent!!!!

[med6753]

Making progress with the painting. Just completed the wall behind where the audio system and media PC reside. Once that dries pull down the edging tape and re-install the shelving. You can see the difference in color new vs old above bench 1. That will be done last. Will start on the wall behind bench 2 first next week. It's actually a good thing that I have to pull out both benches. The AC mains wiring behind both has gotten out of hand and this will be a perfect opportunity to clean it up.

This picture due to the lighting and the camera does not show the true color of the new paint. The 2nd picture is accurate. 

[bd139]

I think your camera is bust. It's coming out a shade of green instead of blue 

[Saskia]

Vodafone cable internet shitshow today.
Technician came to install cable and found out that he could not route a cable from the central distribution point to my appartment. He wanted to drill into the outer wall twice, once from the house distribution to the outside (i.e. the basement, and where I live, we are about 3 m below the ocean water line ..., plus on the first floor (to you 'mericans: we start at 0 over here when counting floors ..)

Obviously you do need permission from the home owners association to do that, so no internet today.
They said: maybe we can try DSL, it's a lot slower, more expensive, and we need another 4 weeks to find out if we can get DSL hooked up for you.
 

Why don't I live in a decent country where they have a minimum of services. I mean, even Nigeria is ahead of Germany in terms of Internet. And then the frigging government is tawking about digital revolution and such crap.