Test Equipment Anonymous (TEA) group therapy thread

[bd139]

Probably better. Biochem is the future

Updated design with 10uA and 50uA ranges.

[tggzzz]

@tggzzz, I imagine the answer to this is "all kinds of nope":  https://autoshite.com/topic/34511-ebay-tat-volume-3/page/6567/?tab=comments#comment-2591870

Looks like a K8, which are lovely to fly since they go up like a homesick angel. I've had to force them out of the sky after a couple of hours, when my bladder became distracting and I wasn't appropriately kitted out. I've also sat on top of a runway when there was a 30kt headwind, the (vector) velocity being downwards at ~150ft/min, i.e. no beeping nor booping from the instruments. I got out of the way when another aircraft wanted to take off.

[AVGresponding]

@tggzzz, I imagine the answer to this is "all kinds of nope":  https://autoshite.com/topic/34511-ebay-tat-volume-3/page/6567/?tab=comments#comment-2591870

Looks like a K8, which are lovely to fly since they go up like a homesick angel. I've had to force them out of the sky after a couple of hours, when my bladder became distracting and I wasn't appropriately kitted out. I've also sat on top of a runway when there was a 30kt headwind, the (vector) velocity being downwards at ~150ft/min, i.e. no beeping nor booping from the instruments. I got out of the way when another aircraft wanted to take off.

I wasn't passing comment on the quality of the glider, just on the advisability of "just getting someone to give you a tow to see if it'll fly", without all the necessary hoops jumped through.

[armandine2]

I've got one of those Advance E2 generators as well. Surprisingly good frequency accuracy and stability for its age but the output attenuation is wildly inaccurate at lower output levels.

a newish looking Advance E2 I had in a cupboard is now close to the bench - a rattle inside to investigate.

I have some tech pdf in case.

[Saskia]

3D printing Festool systainer sort boxes ... zees ees taking ages ...

[tggzzz]

@tggzzz, I imagine the answer to this is "all kinds of nope":  https://autoshite.com/topic/34511-ebay-tat-volume-3/page/6567/?tab=comments#comment-2591870

Looks like a K8, which are lovely to fly since they go up like a homesick angel. I've had to force them out of the sky after a couple of hours, when my bladder became distracting and I wasn't appropriately kitted out. I've also sat on top of a runway when there was a 30kt headwind, the (vector) velocity being downwards at ~150ft/min, i.e. no beeping nor booping from the instruments. I got out of the way when another aircraft wanted to take off.

I wasn't passing comment on the quality of the glider, just on the advisability of "just getting someone to give you a tow to see if it'll fly", without all the necessary hoops jumped through.

Ah, yes.

I know an instructor that is qualified to certify and repair K8s. He has a lovely attitude: after anything major with his name on it, he insists on being the first person to fly it. He was a rather apprehensive when "one of his" crashed very visibly; fortunately the pilot had left a suicide note. But that b*ard destroyed a very nice aircraft, the equivalent of crushing a Tek 5 series scope.

I've occasionally applied his verification principles to electronic equipment; sometimes and the other person doesn't appreciate being put on the spot, which is useful information in itself.

The instructor is also on TekScopes, but does not have GAS to a serious extent: Tek 453, some Marconi RF comms testers, one of my risetime testers, and a Weston Standard cell I gave him for his voltmeters.

[Zenith]

... and he said he was selling three, one after the other. The first went for £75,  I got the second for £27, the third went for £85.

That's the easyJet pricing strategy. Hgh price a month in advance since you need to be there on that day for that planned event. High price a couple of days in advance, since you need to be there on that day for that unplanned event. Lowest price a week in advance, because it is a "wouldn't be nice if", it allows esayJet to plan, and you could change your mind.

For non-fleabay auctions the high-low-high isn't unusual. I guess the psychology is for the first ones "I can't miss getting one of these necessary items" and for the last ones "heck, I might miss one of these desireable items".

I'm sure that's true, but a lot of things must come into play such as how often the item comes up. A lot of TE doesn't appear that often. For other things you can look at the history of past sales and be fairly confident that if you miss this one, another will come along. It must also depend on just who happens to be looking.

At car auctions where they were selling off numbers of three year old ex-fleet cars, you could say within about 5% what a particular car was likely to sell for. Most of the buyers with an eye to forecourt prices and margins, were not going to overbid.

Another factor in fleabay has to be whether the item is available for personal collection and whether it's feasible to collect it and also whether it's personal collection only, which must restrict the market - but great if it's near you. For a lot of TE, it's at least very desirable to be able to see it and the seller in the flesh before parting with the loot.

[med6753]

Road trip today. Decided to rescue the Tek 2235 in this CL ad. I know I'm probably in for mucho aggravation due to their known PSU issues but it will keep me busy. 

Full tear down once I get it.

https://newjersey.craigslist.org/ele/d/sparta-tektronix-mhz-oscilloscope/7510713135.html

[Zenith]

You old softy. You just can't bring yourself not to help an oscilloscope in distress.

[bd139]

That one’s a fucking skunk. Wear ear defenders.

[TERRA Operative]

Road trip today. Decided to rescue the Tek 2235 in this CL ad. I know I'm probably in for mucho aggravation due to their known PSU issues but it will keep me busy. 

Full tear down once I get it.

https://newjersey.craigslist.org/ele/d/sparta-tektronix-mhz-oscilloscope/7510713135.html

I have a video on upgrading the PSU in these, among other things. Check the description for links to parts lists etc.
(Don't forget to check the transformer has had the CRT filament winding unwound a bit to reduce the filament voltage! Tekwiki has the details.)

youtube.com/watch?v=lrXCVg6T-ek

(Like and subscribe! Hit that bell icon! This video brought to you by GenericVPN and GenericMobileGame! )

[bd139]

Ah that feeling when you find out the 2N3347 is not a PNP dual transistor. It’s an NPN one. The one data sheet on the internet is wrong. And of course that will be why my circuit is not working 

Edit: it now works. The findings so far:

1. The 2N3347 is a dual NPN transistor not a dual PNP transistor.
2. The emitter pins are NOT at the same end as the tab unlike every other TO18/TO5 package out there.

Now those problems are out the way and the circuit turned upside down basically, it works nicely.

Performance data has been tested.

settability = +/- 0.2uA
+/- 1V supply swing = +/- 1uA (1%)
0-4.7K load swing = +/-0uA (not measurable with the Fluke 25 in uA anyway)

This is NOT temperature stable. The circuit is CTAT. To compensate we'd need to sum with a PTAT source at the junction which I can't be arsed with. I'm happy with 5% or so here.

[factory]

Weird the D.A.T.A. Digest transistor 1994 book (size of an ancient telephone directory) I have, puts the 2N3347 under the "low power silicon PNP" section, TO-77 package, but it doesn't have the pinout.

Suggested replacements are IT137, NTE82, SK9115 and 2N3726.

David

[med6753]

Road trip today. Decided to rescue the Tek 2235 in this CL ad. I know I'm probably in for mucho aggravation due to their known PSU issues but it will keep me busy. 

Full tear down once I get it.

https://newjersey.craigslist.org/ele/d/sparta-tektronix-mhz-oscilloscope/7510713135.html

I have a video on upgrading the PSU in these, among other things. Check the description for links to parts lists etc.
(Don't forget to check the transformer has had the CRT filament winding unwound a bit to reduce the filament voltage! Tekwiki has the details.)

youtube.com/watch?v=lrXCVg6T-ek

(Like and subscribe! Hit that bell icon! This video brought to you by GenericVPN and GenericMobileGame! )

Between your video and BD's thread I'll be sure to spread the pain. 

[BU508A]

Ah that feeling when you find out the 2N3347 is not a PNP dual transistor. It’s an NPN one. The one data sheet on the internet is wrong. And of course that will be why my circuit is not working 

Edit: it now works. The findings so far:

1. The 2N3347 is a dual NPN transistor not a dual PNP transistor.
2. The emitter pins are NOT at the same end as the tab unlike every other TO18/TO5 package out there.

Now those problems are out the way and the circuit turned upside down basically, it works nicely.

Performance data has been tested.

settability = +/- 0.2uA
+/- 1V supply swing = +/- 1uA (1%)
0-4.7K load swing = +/-0uA (not measurable with the Fluke 25 in uA anyway)

This is NOT temperature stable. The circuit is CTAT. To compensate we'd need to sum with a PTAT source at the junction which I can't be arsed with. I'm happy with 5% or so here.

Hmm, I've checked several different sources and every single one is saying PNP.
Produced by New Jersey Semiconductors.

 

Will check my ECA lists this evening.

Edit:
https://alltransistors.com/transistor.php?transistor=3107

[med6753]

Ah that feeling when you find out the 2N3347 is not a PNP dual transistor. It’s an NPN one. The one data sheet on the internet is wrong. And of course that will be why my circuit is not working 

Edit: it now works. The findings so far:

1. The 2N3347 is a dual NPN transistor not a dual PNP transistor.
2. The emitter pins are NOT at the same end as the tab unlike every other TO18/TO5 package out there.

Now those problems are out the way and the circuit turned upside down basically, it works nicely.

Performance data has been tested.

settability = +/- 0.2uA
+/- 1V supply swing = +/- 1uA (1%)
0-4.7K load swing = +/-0uA (not measurable with the Fluke 25 in uA anyway)

This is NOT temperature stable. The circuit is CTAT. To compensate we'd need to sum with a PTAT source at the junction which I can't be arsed with. I'm happy with 5% or so here.

Hmm, I've checked several different sources and every single one is saying PNP.
Produced by New Jersey Semiconductors.

 

Will check my ECA lists this evening.

Edit:
https://alltransistors.com/transistor.php?transistor=3107

Interesting. NTE has no cross reference for it.

[bd139]

Yeah it’s weird. It’s definitely NPN. I buzzed out a few with diode tester. All the same. These are TI 1970 stamped ones. Will see if there’s a catalogue on bitsavers…

I suppose it’s a good excuse to buy a DCA55 or something 

[BU508A]

Yeah it’s weird. It’s definitely NPN. I buzzed out a few with diode tester. All the same. These are TI 1970 stamped ones. Will see if there’s a catalogue on bitsavers…

I suppose it’s a good excuse to buy a DCA55 or something 

I've uploaded a sheet from a Texas Instruments    Semiconductor and Components Data Book 1967/8

Source:
https://www.datasheetarchive.com/2N3347-datasheet.html
Scroll down

[factory]

A dead tree edtion of the Texas databook from 1977 (from the books lot bought at PP auction), it too gives 2N3347 as PNP, oddly the transistors type 2N2604 & 2N2605 that each triode??? is electrically similar to, are not in the book.

David

[bd139]

Thanks both. Much appreciated.

This is extremely weird!

Edit: ok so I have a mix of TI and Motorola ones. Going to test them all quick.

[Specmaster]

@tautech will go for that specialized premix husqvarna certified mix that does cost a bit more but comes without all those pesky additives good for the road but bad for the woods ...

Okay as you wish but can't be bothered with such BS here. I know what works, period !
What model Husky do you have, an Autotune one ?

Don't be bullied by this pollution BS as the little each of us use a saw has zip impact on the environment....whereas if we freeze to death think of all the extra lumber required for our deep sleep box or the gas required to crisp us to cinders. 

If big industry were to do their bit, globally, that would make a massive differance to the enviroment but all time when you have the 2 largest polluters China and the USA doing diddly squod, even if we all had EV cars, we are not going to make a significant differance unless industry does their share. 

[Specmaster]

Yeah it’s weird. It’s definitely NPN. I buzzed out a few with diode tester. All the same. These are TI 1970 stamped ones. Will see if there’s a catalogue on bitsavers…

I suppose it’s a good excuse to buy a DCA55 or something 

Even a cheap Chinesuim tester will confirm that for you.

[bd139]

Yeah I know that but I was looking for an excuse to buy a DCA55 

Anyway back to the Titillating Transgender Transistor Troubles 

[med6753]

Yeah I know that but I was looking for an excuse to buy a DCA55 

Anyway back to the Titillating Transgender Transistor Troubles 

Beam me up Scotty. Even our transistors are going transgender. 

[Specmaster]

You old softy. You just can't bring yourself not to help an oscilloscope in distress.

Well it certainly helps if its a Tektronix of course