Test Equipment Anonymous (TEA) group therapy thread

[VK5RC]

Some more work on the HP 5381A. The thing uses a good old SN7446 as the display decoder and this thing appears to eat displays. The question is why. Well looking into it in detail of the design, the SN7446 is the digit driver and is open collector. The digit mux is done using some discrete generic PNP transistors. The whole thing is current limited by a single 47 ohm resistor per segment.



Throwing all this into LTspice results in this with a crude approximation of a 2.36v drop LED:



So what does this tell you? Well the standing current is 53mA through each of these segments! Even if pulsed that's a bit much for vintage LEDs so no wonder they were blowing up.

So what do we do here? Well I've ordered a bunch of new Kingbright ones which are significantly more efficient so I'm replacing all the displays and the 47 ohm resistors with 220 ohm ones. As the rest of the counter runs luke warm but the display board runs hotter than satan's bollocks, this should reduce the stress considerably!

Edit: considering bagging a Duratool desolder station for this one as I don't fancy having to braid all these displays out https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD01384

I have one of those old HP with an intermittent display - every time I take the cover off it starts to work - so it has been 'maturing' on the shelves for a while!
I would be very interested to see how it works out for you and which model of Kingbright you used, 👍

[Cerebus]

eBay UK find of the day:

Ex BBC AvoMeter 8 mk 5  spares or repair for the bargain price of £399     

Link if you need some amusment.

https://www.ebay.co.uk/itm/402807446887

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

[tonyalbus]

Introducing:



my new US Lab version beta 0.01.
about 8 meters x 3 meters, I can dance tarantella now.. uh feet, inches, sorry whaaat?

A few infos:

1) Relocation from EU to USA. On the 29th March I packed up everything. It arrived here on the 17th of freaking July.... they told me corona times... would you believe them? Muppeeeetsssssss
2) the mains here in US are a shit show, I already found and corrected few errors in the electrical system in my home. Safety forget about it... but for 0.0924 €/KWh I can't complain too much...
3) First project. Spectrum Modem IPV6/64 and pfSense... Tsunami of shit coming... anyway I want and need to learn the IPV6 jazz better...
4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...
5) Good news, shitty blue CAT5 running in the entire home... will put a switch behind those old telephone lines...
6) What I have to do with all 10 Kms of coax cables they wire up in almost every freaking room? I do and not want to have a SAT system and decoders... What I should do with them?

Thanks for all who asked about me and sent PM!

PS: I can't believe it I am back..... ahh finally again TEAAAAAAA

Good to see you Back @Zucca!
wow!! nice space!!

[BU508A]

4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...

What do you want to do? Installing a 25kW transformer in the basement? 

[Specmaster]

Now I know why my Aorus blew up.   

bd... was GigaByte the gig you just quit from...? Might explain the fireworks...

mnem
" ¹/_{2 *} : Made of fire; burned my house down. Would not recommend."

What a shit show, I never ever felt comfortable with their gear anyway. Personally I love my current PSU, a Corsair RM850, seems to be ultra reliable.

[dl6lr]

eBay UK find of the day:

Ex BBC AvoMeter 8 mk 5  spares or repair for the bargain price of £399     

Link if you need some amusment.

https://www.ebay.co.uk/itm/402807446887

The bulb is missing...

S,CNR!

[beanflying]

Moron Seller previously posted by me here tried cancelling and relisting this meter three times in the end costing them $$ 

LOSER
They got positive feedback from the eventual recipient....

[Cerebus]

4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...

What do you want to do? Installing a 25kW transformer in the basement? 

No, he just has to treat one of his two live phases as if it was a neutral.  As if anyone would be crazy enough to design an electricity distribution system like that! 



On a more serious note: this can go horribly wrong if some piece of end equipment was designed and/or implemented under the assumption that 'neutral' and 'ground' are equivalent. I'm thinking of some of the shitshow wiring we've seen in some hot air and soldering stations. If it was me personally I'd want to either inspect, PAT test, or hipot test anything before trying the cowboy (civilised world) <-> (wild west) line voltage adaption technique.

[Cerebus]

What a shit show, I never ever felt comfortable with their gear anyway. Personally I love my current PSU, a Corsair RM850, seems to be ultra reliable.

My longest living computer PSUs have all been either Corsair or Delta. Anecdote is not data and all that, but.

[tggzzz]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

[Cerebus]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

Something that I found hard to believe even at the time. My parents watched it, therefore I had to sit through it. Ignoring the obvious, it was also the tritest, dullest show on TV - it made the potter's wheel look positively captivating. It was like a Smith's song - watch one number and you've effectively seen every other number and experienced the full range of their expressive capabilities. Utter garbage, but then the Great (unwashed) British public was never known for their great taste - in defence of which argument I offer three words "Watney's Red Barrel".

Edit, in L'esprit de l'escalier: [Fx: Eric Morecombe voice] "I'd rather sit and watch every Des O'Conner special ever made than sit through a single episode of The Black and White Minstrel Show".

[BU508A]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

My Fair Lady (1965) or Cabaret (1973)?

[tggzzz]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

My Fair Lady (1965) or Cabaret (1973)?

Those two are positively wholesome by comparison.

[tggzzz]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

Something that I found hard to believe even at the time. My parents watched it, therefore I had to sit through it. Ignoring the obvious, it was also the tritest, dullest show on TV - it made the potter's wheel look positively captivating. It was like a Smith's song - watch one number and you've effectively seen every other number and experienced the full range of their expressive capabilities. Utter garbage, but then the Great (unwashed) British public was never known for their great taste - in defence of which argument I offer three words "Watney's Red Barrel".

I never understood it either, and that includes the material and the presentation.

Fortunately my parents didn't watch it. If they had I would have been elsewhere with a book or soldering iron or chisel

[Andrew_Debbie]

My longest living computer PSUs have all been either Corsair or Delta. Anecdote is not data and all that, but.

Apple for me.  I've got a  2010 MacPro  that is in 24/7 server  duty on the original power supply.

I have a second 2010 and a stack of 2008 Mac Pros that are all on their original power supplies.   One of the 2008 machines was on 24/7 as a server until last year.  I haven't powered it on for a few months, but it likely will start up a gain.

[Specmaster]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

Something that I found hard to believe even at the time. My parents watched it, therefore I had to sit through it. Ignoring the obvious, it was also the tritest, dullest show on TV - it made the potter's wheel look positively captivating. It was like a Smith's song - watch one number and you've effectively seen every other number and experienced the full range of their expressive capabilities. Utter garbage, but then the Great (unwashed) British public was never known for their great taste - in defence of which argument I offer three words "Watney's Red Barrel".

Yeah, my parents also watched it, never saw the appeal personally, much preferred to watch some good comedy programs. I do however admit to enjoying "Love thy Neighbour", a show that attempted to make fun out of the racists.

[Cerebus]

My longest living computer PSUs have all been either Corsair or Delta. Anecdote is not data and all that, but.

Apple for me.  I've got a  2010 MacPro  that is in 24/7 server  duty on the original power supply.

I have a second 2010 and a stack of 2008 Mac Pros that are all on their original power supplies.   One of the 2008 machines was on 24/7 as a server until last year.  I haven't powered it on for a few months, but it likely will start up a gain.

I may be wrong, but if memory serves the MacPro  and aluminium Power Mac power supplies were all manufactured by Delta. I'm not going to disembowel either the 2005 G5 Power Mac or one of the two 2006 MacPros that are sitting here, still working, to prove it however. I have a couple of Delta supplies from last century that still work fine (on their original caps, no less), or did when last powered on in the last year or so.

Delta were always the people to go to for OEM embedded PSUs, if you didn't want to pay (TDK) Lambda prices. 

[Saskia]

Also good experience with Corsair RM, RMi, RMx series. Been running a 1kw RM in my mining rig for months and an RM 750 in the other rig.
Now trying an HM platinum from Corsair hoping it will be similarly nice

[Cerebus]

Yeah, my parents also watched it, never saw the appeal personally, much preferred to watch some good comedy programs. I do however admit to enjoying "Love thy Neighbour", a show that attempted to make fun out of the racists.

At least Rudolph Walker as the black neighbour, Bill Reynolds, gave at least as good as he got. Although "Love Thy Neighbour" attracts scorn nowadays my memory of it is that it did more to puncture prevailing racist attitudes than reinforce them. Your attitude after watching it was that you'd rather have Rudolph Walker than Jack Smethurst as an actual neighbour. As always in British sitcom it was the wives how came over as the truly sensible characters.

An interesting comparison is "Rising Damp" which was pretty much contemporary with "Love Thy Neighbour", where Don Warrington's (black) character, Phillip, always ended up with the upper hand.

I suspect that "Love Thy Neighbour" has aged poorly, more because of the style of comedy (cf "On The Buses") rather than, viewed objectively, the racial content. "Rising Damp" on the other hand is, I dare say, as watchable as it ever was.

[Cerebus]

Fortunately my parents didn't watch it. If they had I would have been elsewhere with a book or soldering iron or chisel

Once I was old enough that it would occur to me to do anything other than sit in front of the TV on a Saturday night with my parents, say 8 or so, so did I. Checking the stats I'm not surprised that it started in 1958, I am surprised that it was still airing in 1978, by which time if I had still been living at home and my parents had put it on they would have been given a stern and earnest lecture on why they should not.

[med6753]

Introducing:



my new US Lab version beta 0.01.
about 8 meters x 3 meters, I can dance tarantella now.. uh feet, inches, sorry whaaat?

A few infos:

1) Relocation from EU to USA. On the 29th March I packed up everything. It arrived here on the 17th of freaking July.... they told me corona times... would you believe them? Muppeeeetsssssss
2) the mains here in US are a shit show, I already found and corrected few errors in the electrical system in my home. Safety forget about it... but for 0.0924 €/KWh I can't complain too much...
3) First project. Spectrum Modem IPV6/64 and pfSense... Tsunami of shit coming... anyway I want and need to learn the IPV6 jazz better...
4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...
5) Good news, shitty blue CAT5 running in the entire home... will put a switch behind those old telephone lines...
6) What I have to do with all 10 Kms of coax cables they wire up in almost every freaking room? I do and not want to have a SAT system and decoders... What I should do with them?

Thanks for all who asked about me and sent PM!

PS: I can't believe it I am back..... ahh finally again TEAAAAAAA

Good to see you Back @Zucca!
wow!! nice space!!

Agreed, nice to have you back.  If I had that much space I could go buck wild with additional boat anchors. 

I know this is asking a lot but try to find a sparkie who knows his arse from his elbow and he can get you at least safely wired for 240V into the room. Beyond that you'll have the issue of plug compatibility and you won't find 240V plug strips so you'll have to make up some sort of distribution point unless your equipment can be re-wired for 120V. 

[Robert763]

4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...

What do you want to do? Installing a 25kW transformer in the basement? 

No, he just has to treat one of his two live phases as if it was a neutral.  As if anyone would be crazy enough to design an electricity distribution system like that! 



On a more serious note: this can go horribly wrong if some piece of end equipment was designed and/or implemented under the assumption that 'neutral' and 'ground' are equivalent. I'm thinking of some of the shitshow wiring we've seen in some hot air and soldering stations. If it was me personally I'd want to either inspect, PAT test, or hipot test anything before trying the cowboy (civilised world) <-> (wild west) line voltage adaption technique.

Being mainland europe all his kit will hae reversible plugs so may have already been tested........

[Robert763]

Yeah, but that one's extra special ex-BBC - one look at it and you tell it was used on the Black and White Minstrel Show.  I'm rather surprised that it doesn't come with a little straw boater and a stripy blazer.

I use two ways of enlightening youngsters as to how much progress our generation enabled:

• yootoob vids of the Black and White Minstrel show, the most popular Saturday night programme in the 1960s and early 70s
• the plot essentials of one of the few movies to win 9 oscars (including best picture), the glossy family-friendly musical "Gigi"

If you want some "good" old british TV comedy try "Forces TV" feeding squaddies 80's TV.......

[ch_scr]

...

whereupon he's all like:

ch_scr  — Today at 6:05 PM
fuck
you know I have to make me one as well?
thanks I guess    

And he means from scratch out of his parts bins, just because... 

But he posted a vid showing how to do what I wanted with the nanoVNA; and damn if he didn't get me back: Next in my yoobToob queue was this little gem, which sucked up another half-hour of my life...
...

Found two reasonable "primary" source for info on the dg-mos fet probe:
T. Hirschbüchler Bachelor Thesis on the "Design of a low-cost 1 GHz Active Probe" with "conception, construction and evaluation"
https://content.instructables.com/ORIG/FQZ/1QZP/IPJTFO82/FQZ1QZPIPJTFO82.pdf
and the layout from elektor with the gimmick-cap on the pcb:
https://www.elektormagazine.com/files/magazine/2004/dolo/040108-PCB.pdf

That link is borked (at least for me); it may be behind a paywall. I've attached the .pdf below. 

Also, I actually found that article while doing my own research; however I didn't agree with two primary features of his construction technique:

1), his pogo pins are just too long. Everything I've read on the subject aside from his article indicates that ~5mm or less is the ideal length here.

And B) the pin spacing is just ridiculously too wide (yes, I understand the reasons) to actually be a useful probe for most of the kind of stuff you'll use it for.  The really good thing aboot the  60dbmcom probe is the big pads for soldering pins to; you can easily reconfigure to match almost any needed pin spacing.   



https://www.ebay.com/itm/174764316127

There's also this one; it supposedly has specs from the actual device (not just copied from the Elektor article), and I like that the total signal path is as short as possible; however, it was 2x the price and completely unreasonable delivery time. Also it does not use the gimmick capacitor and no pad for GND pin, which is part of the reason the Elektor design uses a dual-gate FET.

mnem
 

Here's my hot take on it

[med6753]

4) Second: Wireup/Setup a 220VAC 60HZ Eu/Schuko (thanks to the Germans!) plugs in my US home... this will be a fun one... do you guys wants some videos series about it? If you push me I could start a YT channel...

What do you want to do? Installing a 25kW transformer in the basement? 

No, he just has to treat one of his two live phases as if it was a neutral.  As if anyone would be crazy enough to design an electricity distribution system like that! 



On a more serious note: this can go horribly wrong if some piece of end equipment was designed and/or implemented under the assumption that 'neutral' and 'ground' are equivalent. I'm thinking of some of the shitshow wiring we've seen in some hot air and soldering stations. If it was me personally I'd want to either inspect, PAT test, or hipot test anything before trying the cowboy (civilised world) <-> (wild west) line voltage adaption technique.

Older 240V installs were 3 wire.....Black - hot, white - hot, green - gnd. I believe the code was updated to require a dedicated neutral so it would be.....black - hot, red - hot, white - neutral, green - gnd.

Any device tying neutral and ground together within the device is verboten here and as you stated would have to be checked.