Test Equipment Anonymous (TEA) group therapy thread

[AVGresponding]

Anyone in UK need a death-inator?

https://www.ebay.co.uk/itm/372957387420

(Hewlett Packard 6516A)

I'm tempted but I can't think of a legitimate use for it other than murder.

Ungh!
This is not really looking good. I'd carefully inspect this thing BEFORE I'll get it anything near mains power.
Rust on the outside for a high voltage device is imho never a good sign.
I hope, that the buyer of this thing knows what he is doing.

@bd139: glad, that you want to stay away from it. I'm really interested in reading more posts from you here. 

Agree. Dangerous as hell.

Hahaha. Honestly I am shit scared of high voltages and rather like low voltage stuff so hopefully I'll not kill myself too quickly.

Haha this is where I got my 2.5kV EP psu from.

I saw this earlier, and have to say, it doesn't look anywhere near as safe as mine   

They pack for the apocalypse, only ever had one issue (minor damage to that EP psu from a wrecking ball) and the DPD guy must have tried really hard at that...


Ordered some nickel plate strip for making battery packs from China before last weekend; got an ETA today of 30th of March   

[tggzzz]

When I started contracting, a long time ago when I was about 20, I'd never written a line of C in my life. I spent the weekend before my first day with a copy of K&R and wrote a program to play noughts and crosses.

Nobody noticed the fact that I'd lied my way through the interview! 

Back then C was comprehensible by mere mortals, and there was no need for language lawyers.

Actually there were two C books then, the other being "The C Puzzle Book" which indicated the obvious traps. Non-obvious traps arrived with later versions of C and with more highly optimising compilers.

[SilverSolder]

I've used most languages (including lots of assembler) over the years but C is still my absolute favourite. I like to call it "structured assembly language".

That's pretty much what it is -  a high level assembly language. 

Still, hard to beat assembler (for modest sized projects of course!).

[worsthorse]

I still remember at high school one day when the teacher shut me down, and it did not feel right. Only 2 years later at the university I understood I was damm right and he was a stupid muppet that day.
When I remember it my blood pressure goes up, even today.

I do not want you to regreat it like I did.

Remember the old aphorism:

* Those that can, do.
* Those that can't do, teach.
* Those that can't teach, teach teachers,
* Those that can't teach teachers become an education officer.

Inside every English teacher is a frustrated novelist.
Inside every physics teacher is someone who feels unfairly denied a Nobel prize.
Inside every physical education teacher is a wee grudge-bearing bastard with no more right to walk on God's good Earth than a plague bacterium.

really... it depends. so much of "teaching" depends on the institution's goals and the environment in which teaching is done. in a place with proper goals and infrastructure, a good instructor will shine. in a place with stupid goals and poor infrastructure, the best of instructors will struggle.  i taught at the university level for a while in both kinds of places. in one case, my students were engaged, curious, and appropriately demanding of me. they did well (probably in spite of me). in the other, nothing i did really made much difference and i was reprimanded for assigning well-deserved Cs and Ds.  one thing i noticed: in one place, there were an awful lot of really good teachers. in the other, they were rare.

[worsthorse]

Indeed. Being accidentally effective is not being effective 

Edit: As for faking knowledge, in the "IT trade" it's normal to play this off against the old idiom that in the kingdom of the blind, the one eyed man is king. Thus I got a Perl job once having never written a line of Perl and learning enough of it to look professional in relation to the rest of their staff in the weekend that elapsed between getting the job and starting there. 

When I started contracting, a long time ago when I was about 20, I'd never written a line of C in my life. I spent the weekend before my first day with a copy of K&R and wrote a program to play noughts and crosses.

Nobody noticed the fact that I'd lied my way through the interview! 

    that makes two of us. i got my first software side job under the same sort of circumstances. the project lead wanted to hire me into a management slot but said, you know C right? so if i had to hire you as a senior engineer until i can move you into the dev manager role, you could do that, right?.  i said of course! and spent three feverish days with K&R the monday before i was to start. 

luckily for them (and me) the job turned out to be programmer wrangling rather than programming.   

[med6753]

Anyone in UK need a death-inator?

https://www.ebay.co.uk/itm/372957387420

(Hewlett Packard 6516A)

I'm tempted but I can't think of a legitimate use for it other than murder.

Ungh!
This is not really looking good. I'd carefully inspect this thing BEFORE I'll get it anything near mains power.
Rust on the outside for a high voltage device is imho never a good sign.
I hope, that the buyer of this thing knows what he is doing.

@bd139: glad, that you want to stay away from it. I'm really interested in reading more posts from you here. 

Agree. Dangerous as hell.

Hahaha. Honestly I am shit scared of high voltages and rather like low voltage stuff so hopefully I'll not kill myself too quickly.

Why do you think I wear rubber gloves when probing around in the 535A? The +100V, -150V, and +225V are enough to give you pause. But add to that +325V and +500V floating around and it makes your hands tremble a bit. AND....if you look close you can see an arc jump to your probe when checking the +500V. 

+3KV? Fawk you. 

[tautech]

Why do you think I wear rubber gloves when probing around in the 535A? The +100V, -150V, and +225V are enough to give you pause. But add to that +325V and +500V floating around and it makes your hands tremble a bit. AND....if you look close you can see an arc jump to your probe when checking the +500V. 

+3KV? Fawk you. 

Pretty much the same in any CRO's EHT area, most are somewhere around 2kV and a few nudge 3kV before they're trebled, quadrupled or quintupled.....yeah that stuff gives me the screaming hebe jeebies without a decent HV probe but just the EHT is not too bad providing the test points are readily accessible.
Still you want probes and leads that are rated for these elevated voltages and better still with clips so you can connect when OFF and power ON for measurements.
I don't at all miss fixing CRO's. 

[bd139]

Yeah exactly. Tek 2235...



To do this measurement I just soldered the test leads on the (disposable) BM22s to the test points and stepped well back 

It actually was quite happy to about 2.1KV and then made some nasty noises. Survived fine!!!! Nice DMM that.

Note the 87V in the background looking worried 

[med6753]

Why do you think I wear rubber gloves when probing around in the 535A? The +100V, -150V, and +225V are enough to give you pause. But add to that +325V and +500V floating around and it makes your hands tremble a bit. AND....if you look close you can see an arc jump to your probe when checking the +500V. 

+3KV? Fawk you. 

Pretty much the same in any CRO's EHT area, most are somewhere around 2kV and a few nudge 3kV before they're trebled, quadrupled or quintupled.....yeah that stuff gives me the screaming hebe jeebies without a decent HV probe but just the EHT is not too bad providing the test points are readily accessible.
Still you want probes and leads that are rated for these elevated voltages and better still with clips so you can connect when OFF and power ON for measurements.
I don't at all miss fixing CRO's. 

Of course anything beyond the HV oscillator transformer is verboten unless the HV probe is in hand. Even with it I don't like venturing in that area unless absolutely necessary.   

[med6753]

Yeah exactly. Tek 2235...



To do this measurement I just soldered the test leads on the (disposable) BM22s to the test points and stepped well back 

It actually was quite happy to about 2.1KV and then made some nasty noises. Survived fine!!!! Nice DMM that.

Note the 87V in the background looking worried 

I remember when you did that. All I gotta say is you is nuts boy. 

Edit...Woo Hoo....post 5000. 

[bd139]

Not nuts. Sensible. I wasn't anywhere near it 

My father was nuts. He had a "Philips multitester" which was rated up to 1.2KV DC and didn't have any shrouded leads or anything. Made his own HT probe out some mains flex, normal resistors from Tandy, a pen and hot snot and merrily poked around inside CRTs with it  .

[tautech]

Why do you think I wear rubber gloves when probing around in the 535A? The +100V, -150V, and +225V are enough to give you pause. But add to that +325V and +500V floating around and it makes your hands tremble a bit. AND....if you look close you can see an arc jump to your probe when checking the +500V. 

+3KV? Fawk you. 

Pretty much the same in any CRO's EHT area, most are somewhere around 2kV and a few nudge 3kV before they're trebled, quadrupled or quintupled.....yeah that stuff gives me the screaming hebe jeebies without a decent HV probe but just the EHT is not too bad providing the test points are readily accessible.
Still you want probes and leads that are rated for these elevated voltages and better still with clips so you can connect when OFF and power ON for measurements.
I don't at all miss fixing CRO's. 

Of course anything beyond the HV oscillator transformer is verboten unless the HV probe is in hand. Even with it I don't like venturing in that area unless absolutely necessary.

Trouble is, with most portable CRO's the EHT area is under considerable stress and a common failure point so unless you have the understanding, tools and the confidence to go there many scopes can be not quite right in the display. Yeah it can be scary stuff for the faint hearted and now I just don't need the stress.
When I look back on all the time I spent on CRO's I'm only thankful for what I learnt yet I admire the efforts like yours to restore these old darlings albeit a $500 DSO can do much more.

[Cerebus]

To do this measurement I just soldered the test leads on the (disposable) BM22s to the test points and stepped well back 

It actually was quite happy to about 2.1KV and then made some nasty noises. Survived fine!!!! Nice DMM that.

I've got a 'free' one of those that arrived with my new scope the other day. Haven't had a chance to put it through its paces yet but first impressions are good based just on look and feel. Perhaps I'll get a supply and the 34461A out and see how it holds up.

[bd139]

Ahh a telonic shopper  .

Yeah it's well put together. It has proper protection features inside it being Brymen. I take mine to hamfests to poke things with. Also to note they go for £22 on ebay at average if you have some surplus (I think I ended up with about 5) so profitable!

Edit: minor diversion on topic from the other day. Have located a suitable two wheeled deathtrap. Has disc brakes and isn't made of poo. Dawes Ultra Galaxy. Going to go and play with one on Saturday.

[med6753]

I do enjoy working on the old iron just being mindful of the dangers. Under these 2 covers is the HV supply and divider assembly. But if you notice the warning message on the right emphasizes more the dangers of the +350V and +500V floating around the rest of the scope. And what's even more amazing is those voltages are distributed via what appears to be ordinary 24 gauge solid conductor wiring. Just like the rest of the wiring harness. So you can't tell just by looking at the wiring the high potential that may be right there to bite you in the arse.

[bd139]

I meant to finish writing this earlier but I got distracted by more Edexcel fail. This time tangents on a circle which I couldn't remember how to do as I never used that at all.

On high voltages I noticed on Soldersmoke podcast the other week that Bill Meara gave up working on tube kit (radios) since he got a family. In fact some of the old stuff he's got gets eviscerated for parts to use in transistor kit. I'm inclined to agree with him these days. When you do a risk trade off it's not good if you have responsibilities. Then again I'm buying a bicycle so that's probably got a higher mortality risk 

[factory]

And now back on topic again, I've just noticed that one of the small panel mounted sockets for component leads is actually broken and the missing piece of plastic is actually missing otherwise I could just glue it back on. Does anyone know of where these may be available from, the smallest so far that I have come across has been 2mm and I think these are 1mm. They look to be pretty corroded anyway so it would be nice to replace all 4 of them.

The unit is so sensitive that if I use leads with 4mm bananas and crock clips on the other end (1m long) on lower values the meter can actually read the capacitance between the leads as well. I have a very short set of leads that could be used if necessary, but its so much better to just push the capacitors leads directly into the sockets. I like the way that they have arranged the sockets to provide maybe the 3 most common pitches between the leads to maximise the accuracy of the readings, awesome.

They look very familiar, do you still need some?

David

[Cerebus]

Ahh a telonic shopper  .

Yeah it's well put together. It has proper protection features inside it being Brymen. I take mine to hamfests to poke things with. Also to note they go for £22 on ebay at average if you have some surplus (I think I ended up with about 5) so profitable!

Got it in one.

Just had a quick play, DC only, 0-30V versus the 34461A. The BM22 never differed by more than 1 in the final digit, so quite a bit better than the 1% +2 digits spec that's on the data sheet for it. Easily worth the £22 quid if one was to actually pay for one.

[Specmaster]

Yeah exactly. Tek 2235...



To do this measurement I just soldered the test leads on the (disposable) BM22s to the test points and stepped well back 

It actually was quite happy to about 2.1KV and then made some nasty noises. Survived fine!!!! Nice DMM that.

Note the 87V in the background looking worried 

Yeh, those Brymen's are pretty good, but I have 3 old analogue meters that will thrash the pants off that. I have an Avo 8 with a 3KV range and a TMK 700 and also Kyoritsu 1400 both of which have a 5KV range. Even an Avo 7 analogue meter has 2.5KV range as standard, whats the fuss about   

Edit:
Yeah, they gave those away with if I remember a Rigol scope?, never sent me one with my Brymen BM867s, bastards 

[bd139]

At least you can still get the batteries for the Brymen

[Specmaster]

At least you can still get the batteries for the Brymen

True, that being said, the batteries for the Avo's are still available but pricey, BUT, not required when measuring voltage though.   

[bd139]

I just dropped my BM22s three times on purpose from the desk. Now go do that with an Avo 

[tautech]

At least you can still get the batteries for the Brymen

True, that being said, the batteries for the Avo's are still available but pricey, BUT, not required when measuring voltage though.   

A stack of LR44 button cells and a bit of shrink sleeve is the cheapest replacement for those 15V cells. 

[Specmaster]

And now back on topic again, I've just noticed that one of the small panel mounted sockets for component leads is actually broken and the missing piece of plastic is actually missing otherwise I could just glue it back on. Does anyone know of where these may be available from, the smallest so far that I have come across has been 2mm and I think these are 1mm. They look to be pretty corroded anyway so it would be nice to replace all 4 of them.

The unit is so sensitive that if I use leads with 4mm bananas and crock clips on the other end (1m long) on lower values the meter can actually read the capacitance between the leads as well. I have a very short set of leads that could be used if necessary, but its so much better to just push the capacitors leads directly into the sockets. I like the way that they have arranged the sockets to provide maybe the 3 most common pitches between the leads to maximise the accuracy of the readings, awesome.

They look very familiar, do you still need some?

David

Yes I do still need some but PA0PBZ has some slightly different ones that he is kindly sending to me. But as a back up just in case, do you know where they are available from, I keep drawing a blank in my searches.

[Specmaster]

At least you can still get the batteries for the Brymen

True, that being said, the batteries for the Avo's are still available but pricey, BUT, not required when measuring voltage though.   

A stack of LR44 button cells and a bit of shrink sleeve is the cheapest replacement for those 15V cells. 

That is also very true, but in actual fact when my battery expires, I'm not going to bother replacing it, whats the point when the other meters are better for resistance reading? Where I like use analogue meters is when working on older gear where the test voltages were taken with a 20,000OPV meter otherwise the circuits will not react in the same fashion and also for measuring fast changing voltages such as you find in audio equipment etc.