Test Equipment Anonymous (TEA) group therapy thread

[McBryce]

OK, got it. Now that explains why I have a deer in the headlights look on my face. 

This will make sense to you and I more or other non RF nerds 

My son drew something extremely similar when he was 2 years old

McBryce.

[bd139]

He was an RF natural 

Random question: I have been asked of those Korad power supplies are any good, particularly for a cheap ass who wants to charge some SLA batteries for his radios. I've seen some mixed responses to that. My answer is no but he's even cheaper than me. Thus does anyone know if they are half decent these days? It would be the Tenma version of it from CPC which are 50 smackers here at the moment.

[tautech]

He was an RF natural 

Random question: I have been asked of those Korad power supplies are any good, particularly for a cheap ass who wants to charge some SLA batteries for his radios. I've seen some mixed responses to that. My answer is no but he's even cheaper than me. Thus does anyone know if they are half decent these days? It would be the Tenma version of it from CPC which are 50 smackers here at the moment.

I’m even cheaper and got K305D’s for ~$30. Had one running for 4 weeks recovering a 150ah SLA.

[bd139]

Those are switchers aren't they? Not sure that would wash with a ham. He's already using the SLAs because of RFI

[tautech]

Those are switchers aren't they? Not sure that would wash with a ham. He's already using the SLAs because of RFI

Yep, SMPS.
FFS tell him to build a linear PSU, it ain't hard.

[Ero-Shan]

1.) The Philips LCR-meter is here, but still unpacked.

2.) My pictures should get better by the help of a Lumix DMC-LX100.

3.) Congratulate if you want, I'll celebrate anyway: My first two devices are certified under the RED.
(Now come the hard ones, but not today.)

1. You mean un-unpacked, don't you?

3: Congratulations! But what is 'the RED'? Did I miss something?

2. Now that you have a decent camera, flood us with great pictures! 

[bd139]

Those are switchers aren't they? Not sure that would wash with a ham. He's already using the SLAs because of RFI

Yep, SMPS.
FFS tell him to build a linear PSU, it ain't hard.

I wouldn't trust this guy with a soldering iron. I agree though.

[tautech]

RF is a "no go" zone for me. Too much voodoo wizardry. 

That was me to a couple of years back before I got my first SA and that wasn't by choice because I have to sell these blinking things I'd better find out something about them ! 

Honestly I was shitting myself that I'd blow the bloody thing up but with a few tips and pointers from the RF guys here I haven't thus far ! 
And I'm on my 3rd one too !

So far I'm keeping well clear of any high power RF and pottering around with the many other things they can do.

When you get bored with scopes Med there's another world just waiting for you to discover. 

[med6753]

I'm a simple mind. Don't bore easily. I've been fascinated with that little green analog line since I was about 16 years old and it still makes me giggle. 

[VK5RC]

You know you NEED one!
They come with cookies!
😜

[beanflying]

You know you NEED one!
They come with cookies!
😜

We have seen your shelves of gear we know what R_eeF_a madness does to a Man 

[tautech]

I'm a simple mind. Don't bore easily. I've been fascinated with that little green analog line since I was about 16 years old and it still makes me giggle. 

Me just a few years earlier, I'd built a tube PSU for various projects I wanted to do and even the little I knew about electronics back in the '70's I knew enough that this PSU should have lowish ripple yet I had no idea I could've measured it in AC mode with dad's multimeter. 
So I calmly asked my science teacher if I could use the labs CRO to test this homemade PSU for ripple and next day dragged it onto the school bus ready for lunchtime learning of how a scope works. 
He didn't have a clue and I'd read up just enough to more than likely blow the bloody thing up as I wanted to measure ripple on a 320V supply. 
After he asked me how much voltage this hillbilly PSU on some old TV chassis made he kept right outta my way, I think with a resus kit just in case I got zapped. 
Anyways, it was a winner with only a couple of volts ripple and good enough for the projects I had in mind.

Still the bloody thing got me one day from the 700V across the rectifier tube and lucky there was a bed to land on on the other side on my room.

[med6753]

You know you NEED one!
They come with cookies!
😜

I'm diabetic. Cookies are on the "no fly" list. 

[med6753]

You know you NEED one!
They come with cookies!
😜

We have seen your shelves of gear we know what R_eeF_a madness does to a Man 

Yep, and currently no room for more. I'd have to move. 

[VK5RC]

You know you NEED one!
They come with cookies!
😜

We have seen your shelves of gear we know what R_eeF_a madness does to a Man 

And there is nothing wrong with that, sir!
Seriously some laser envy happening here, but I would not trust myself with one after this weekends effort.
I replaced a screen in my daughter's iPood touch series 5 with an about 4mm bend in the frame - I couldn't straighten the bend out - but put on new screen and put a small crack in that! At least better than before.
Replaced a screen in the same daughter's Samsung s7, it all went back together, fired up - looked great - over 24hrs - slow infusion of purple - God knows what I did wrong, but at $140+ per screen I awarded my self 'penis fingers' award! The back panel is heat glued - after closing up - I gave the unit a gentle warm - easily held in the hands - I wonder if that f***ked the screen?

[Specmaster]

@BD, how's the 1740A, is it now sporting 4 lovely feet yet?

Today there was a nice Fluke 8842A on ebay, listed today and already sold (or removed but it appears to be sold) for £50  (no AC module though but still a good price)

[Kosmic]

He was an RF natural 

Random question: I have been asked of those Korad power supplies are any good, particularly for a cheap ass who wants to charge some SLA batteries for his radios. I've seen some mixed responses to that. My answer is no but he's even cheaper than me. Thus does anyone know if they are half decent these days? It would be the Tenma version of it from CPC which are 50 smackers here at the moment.

Dave reviewed one.

[bd139]

@BD, how's the 1740A, is it now sporting 4 lovely feet yet?

Today there was a nice Fluke 8842A on ebay, listed today and already sold (or removed but it appears to be sold) for £50  (no AC module though but still a good price)

Got three feet at the moment. Will print last one this afternoon. Been too busy! 

That is indeed a good price.

Random question: I have been asked of those Korad power supplies are any good, particularly for a cheap ass who wants to charge some SLA batteries for his radios. I've seen some mixed responses to that. My answer is no but he's even cheaper than me. Thus does anyone know if they are half decent these days? It would be the Tenma version of it from CPC which are 50 smackers here at the moment.

Dave reviewed one.

Thanks for that. It also blew up 

I have suggested he gets a Thurlby PL154 (what I use as a charger) but he won't budge on "no second hand".

[Kosmic]

Thanks for that. It also blew up 

haha didn’t know, only watched the first video 

[med6753]

Thanks for that. It also blew up 

haha didn’t know, only watched the first video 

That is a massive fail. I would expect a linear supply if it was going to fail to suddenly output nothing.....not jump up to 56V. Can you imagine what would happen if you had a 3.3V logic board connected when that happen? That would be spectacular flames that would make bd139 proud. 

[Specmaster]

@bd139  If your looking for a reasonable cheap bench power supply, look around eBay for one of these Chinese built  ones like the one I got a couple of years ago, 30V 5A linear with a bag arse multi tap transformer in it, weighs a metric ton, has a fan but it only cuts in if you're drawing anywhere near its max rating, personally I have never taken anything higher than 1.5A from it so the fan stays off which is fine for me. These do come in other ratings, 15V 3A and also 60V 2A. Be careful though as their there are also some that are switchers, also work well but the fan runs all the time and they are very lightweight, I have of those as well, but the linear one is the better of two.

It has never let me down and the current / volt regulation is actually pretty good, only issues I have with it is that it does not feature a load switch and there is no way of locking the adjustments, apart from that a cracking bit especially given the price I paid £15 although these days they are considerably more than that but they crop up as 2nd from time to time.

I also went to my local Lidl store today and in their Middle of Lidl special buys area I spotted this rather handy tool holder with illuminated magnifying glass with 2.5 & 5x optics and it also comes with vertical iron holder which will accept almost any iron I think, for only £5.99, loving mine, ideal for a small bench top because of the small footprint.     

[bd139]

See below 

That is a massive fail. I would expect a linear supply if it was going to fail to suddenly output nothing.....not jump up to 56V. Can you imagine what would happen if you had a 3.3V logic board connected when that happen? That would be spectacular flames that would make bd139 proud. 

Have you noticed how many Mastech power supplies I  have owned? I've fixed a lot but owned precisely ONE and that was a very long time ago

All the cheap ones are nasty as fuck. There's usually a cost cutting thing in them which goes bang pretty quickly. I was going to write a detailed rant about this but decided that a visual explanation is better:



I have fixed at least 5 that have done this over the years. And 3 with other problems, usually someone shorted the output diode by connecting a battery the wrong way across it 

Edit: for some absolutely stupid reason the failed position of the relay is always full voltage. I don't know why they do that. The whole design works rather well apart from that gigantic cock up. I suspect these are "cut and paste" designs mostly. I've seen several variants with exactly the same schematic.

[worsthorse]

That’s looking pretty good that. The way this is going I’m going to have a laser table next year 

Can I not tempt you with other/better TEA ? 

Sweet!  Unfortunately, I am pretty sure that I am not going to sell enough stuff at the hamfest this weekend to afford one of those, so I will continue to delude myself that my sixty dollar nanovna is just as good.

 

[xrunner]

Made up a simple test board for the NanoVNA, like others seen on the internets. You can test caps, inductors, and resistors or make a Pi or T arrangement. Shown are the readings from a 100 pF cap and 680 ohm resistor.

[worsthorse]

@bd139  If your looking for a reasonable cheap bench power supply, look around eBay for one of these Chinese built  ones like the one I got a couple of years ago, 30V 5A linear with a bag arse multi tap transformer in it, weighs a metric ton, has a fan but it only cuts in if you're drawing anywhere near its max rating, personally I have never taken anything higher than 1.5A from it so the fan stays off which is fine for me. These do come in other ratings, 15V 3A and also 60V 2A. Be careful though as their there are also some that are switchers, also work well but the fan runs all the time and they are very lightweight, I have of those as well, but the linear one is the better of two.

That looks like a knockoff of the Tekpower TD3005D, which is a linear. I have one. Cost about a hundred bucks and works well.