Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Soldering naked is just plain crazy!

And not an image I want to see. 

   PAY. A. TTENTION!

mnem
Situational Awareness, yo.

[mnementh]

I hate xMas...   

Zucca is DEFINITELY on the naughty list.

mnem

[mansaxel]

Isn't PostNord referred to as LostNord?

McBryce.

It's "PostMord", because it has removed all working parts of A Real Post Office in exchange for... "something".

[med6753]

Reference the attached partial schematic of the RCA 54-45 scope for this discussion.

After replacing all the resistors as well as tubes V1 and V2 I STILL had vertical offset issues where the trace would not center vertically on the CRT. Absolutely no upward movement but lots of downward movement. In order for the trace to center vertically on the CRT both plates on V2 (pins 6 and 1) need to be equal. In order to get them equal the grids (pins 7 and 2) need to also be equal. And that's where the issue was. The grid of pin 7 was sitting at about +124VDC (schematic indicated +82VDC) and the highest I could get the grid of pin 2 with the vertical position control was approx +110VDC. That 14V delta was causing the offset. The question is why?

When this scope was designed line voltage averaged 117VAC to 120VAC. My line voltage is 125VAC. Also, modern electrolytic capacitors have a lower ESR than the even when the original aluminum can was new. Result? Much higher B+ and that's what is upsetting the vertical circuit. Now the EICO 430 that this scope is based upon has an OA2 VR tube to regulate the B+. RCA went cheap and deleted the VR tube. So how to fix? I needed to either lower the grid voltage on pin 7 or raise the grid voltage on pin 2. The simplest solution? Bump up R9 to lower the grid voltage on pin 7. Adding 22K in series with the 47K did the trick. I now can center the trace vertically as well as have adequate upward deflection.

So the scope is put back together and will go into a burn-in cycle for the 4th time. The other 3 cycles were a total fail. If it passes this project is done.

[mnementh]

Fucks sake. They sent my package to the second wrong depot 

"and it will be delivered as soon as possible"

... and here also - my linear rail Y-axis retrofit is "arriving later than expected" but the expected delivery day hasn't changed! 

(Attachment Link)

Meanwhile, here in the frozen Great White North, I've received 2 of 3 packages from Amazon that weren't due until Friday.  And for one of them, that INCLUDES delay caused by the usual PUNTOLATER fuckups delivering it to my neighbor instead of me... 

I feel like I'm in a episode of The Twilight Zone...

mnem

[bd139]

@med6753: smells dodgy to me. Id' have chucked it on a variac first and checked it across various supply voltages. Well I would if I had that scope and hadn't sold my variac. I do notice with mains voltages touching 250v here instead of the correct 230v that pass transistors get a little warmer 

[med6753]

@med6753: smells dodgy to me. Id' have chucked it on a variac first and checked it across various supply voltages. Well I would if I had that scope and hadn't sold my variac. I do notice with mains voltages touching 250v here instead of the correct 230v that pass transistors get a little warmer 

I don't have a variac so I'm gonna go with my gut here. Yea....maybe dodgy but it's working.

[med6753]

Fucks sake. They sent my package to the second wrong depot 

"and it will be delivered as soon as possible"

... and here also - my linear rail Y-axis retrofit is "arriving later than expected" but the expected delivery day hasn't changed! 

(Attachment Link)

Meanwhile, here in the frozen Great White North, I've received 2 of 3 packages from Amazon that weren't due until Friday.  And for one of them, that INCLUDES delay caused by the usual PUNTOLATER fuckups delivering it to my neighbor instead of me... 

I feel like I'm in a episode of The Twilight Zone...

mnem
(Attachment Link)

[Cerebus]

Cf old aphorism: "Here at AT&T we treat everybody equally, from kings and queens to the scum of the earth".

Some us of a certain age will, of course, remember Lily Tomlin as a certain telephone operator.

[worsthorse]

I took the easy route, knowing there was a low probability of success.  I ordered a T9 LED light what would be an almost drop in replacement for the tube and "electronic ballast"  (aka switch mode power supply) in my now-disassembled bench lamp.  It arrived tonight and, indeed, it would be an easy replacement. It even came with clips to hold the light in the fixture.

This is what I was talking about before. No matter WHAT LED light source you use, you WILL have to build your own nice, quiet, resistor-ballast linear power supply for it. There pretty much is NO SUCH THING as a "quiet" LED power supply; the entire industry, and all the specialty silicon that has evolved around it, is based on modular CC buck converters using PWM regulation. Don't send it back; gut it and do the job you know you need to do anyways. 

mnem
"Don't turn it on; take it apart!"

* worsthorse hangs his head in shame

I know, I know. I was being hopeful and lazy (note the statement in my original post, I took the easy route, knowing there was a low probability of success). If it worked, problem solved, and on to something more interesting. Plus amazon returns.  The light I bought is glued together; getting to the supply will destroy the case, which is the reason I decided to try it.  So now to order something with a supply I can easily remove or to build something from scratch.

edit: that said, the sheer level of RF noise this particular LED supply put out was quite impressive. i've seen noisy LED supplies but nothing quite like this. it was worth trying it out just to see how bad it could get.

[Cerebus]

Is this junk or not?



https://www.hozan.co.jp/E/catalog/Tweezers/P-831.html

Most probably, yes it's junk. I have a similar one that's NFG. I've come to the conclusion that none of these suction pick devices work unless they are connected to a proper vacuum line or a venturi suction generator on an air line.

[med6753]

Cf old aphorism: "Here at AT&T we treat everybody equally, from kings and queens to the scum of the earth".

Some us of a certain age will, of course, remember Lily Tomlin as a certain telephone operator.

I remember. And she always had her hand inside her blouse. 

[bd139]

@med6753: smells dodgy to me. Id' have chucked it on a variac first and checked it across various supply voltages. Well I would if I had that scope and hadn't sold my variac. I do notice with mains voltages touching 250v here instead of the correct 230v that pass transistors get a little warmer 

I don't have a variac so I'm gonna go with my gut here. Yea....maybe dodgy but it's working.

To note I meant the scope was dodgy not your fix. Anything that works is good for me 

[mnementh]

Is this junk or not?

   https://www.hozan.co.jp/E/catalog/Tweezers/P-831.html

Specs say it's SS tube and silicone bellows/cups; aside from those parts there's not much to go wrong unless the Leuer-lock end of the handle is ridiculously thin molded ABS or somesuch. I like that the SS tube has a flare at the end; the little cheapie Vacu-pick that came with my Aoyue 2702 DOESN'T have that, and it can be a bit of a PITA with the cups getting knocked off in casual handling and having to chase them down like errant pet crickets. Boy does that silicone bounce. 

Mostly, I think it depends on how you work; the "Squeeze to pick/squeeze-to-release" models are generally cheaper and no moving parts to wear out, but the amount of force required to "squeeze & release" can be a hindrance when trying to place extremely precisely (like BGA rework) but for most general-purpose rework are good enough. The "squeeze to pick/press valve button to release" models are better for extreme precision placement; the reduced force required to release makes it easier to keep the part positioned "exactly so". But... they cost more and the valve wears out.

FWIW, that MFR at least bothered to create & post a spec sheet, unlike mine. And cheap as they are, they still work 15 years later.

BELAY THAT. IT'S JUNK.  Looking again, I see it has the same fatal flaw as the old squeeze-bulb models had: the middle part of the body is rubber, which will flex and cause the business end to move as you squeeze to release the part. Run, don't walk, in the opposite direction of ANY parts picker that doesn't have a single-piece solid body.

mnem

[SeanB]

I took the easy route, knowing there was a low probability of success.  I ordered a T9 LED light what would be an almost drop in replacement for the tube and "electronic ballast"  (aka switch mode power supply) in my now-disassembled bench lamp.  It arrived tonight and, indeed, it would be an easy replacement. It even came with clips to hold the light in the fixture.

This is what I was talking about before. No matter WHAT LED light source you use, you WILL have to build your own nice, quiet, resistor-ballast linear power supply for it. There pretty much is NO SUCH THING as a "quiet" LED power supply; the entire industry, and all the specialty silicon that has evolved around it, is based on modular CC buck converters using PWM regulation. Don't send it back; gut it and do the job you know you need to do anyways. 

mnem
"Don't turn it on; take it apart!"

* worsthorse hangs his head in shame

I know, I know. I was being hopeful and lazy (note the statement in my original post, I took the easy route, knowing there was a low probability of success). If it worked, problem solved, and on to something more interesting. Plus amazon returns.  The light I bought is glued together; getting to the supply will destroy the case, which is the reason I decided to try it.  So now to order something with a supply I can easily remove or to build something from scratch.

edit: that said, the sheer level of RF noise this particular LED supply put out was quite impressive. i've seen noisy LED supplies but nothing quite like this. it was worth trying it out just to see how bad it could get.

Well, going to the Post Orofice tomorrow, and hoping small packet number 2, ordered the same time, from the same seller (Electronics Alice, got that from Big Clive), but which was in a different currency, so 2 fleabay transactions...... Then have to pay SAPO for the privilege of getting the parcel, but at least that is going to be fixed at R28 per small packet, no customs. Linear LED panels, from a Diode Gone Wild recent video, where he took a look at them, with his Caat, and his Russian oscilloscope, and that lovely voice. linear panels with a very high efficiency, and a lot of flicker, but I want them to modify to a much lower power, probably around 3W instead of the 10W claimed, and add a little filtering.

[Kosmic]

Question for Ender 3 owners, which upgrade do you consider mandatory ? Other than the glass bed.

I might have a 3d printer incoming 

The aluminium extruder upgrade is the only other upgrade I would consider manditory. The original extruder is made of something softer than PLA and will wear away pretty quickly. All the other filament guides etc seem to be useless and make changing the filament much more difficult. Tried them all, binned them all. I have the Pro version that has the fan on the bottom. If you have ordered the standard version (with fan on top) the fan shroud might be useful to stop bits of plastic falling in.

McBryce.

Thanks for the recommendation. just ordered the aluminium extruder. I got the Ender 3X so the glass bed is coming with the printer.

[mnementh]

I took the easy route, knowing there was a low probability of success.  I ordered a T9 LED light what would be an almost drop in replacement for the tube and "electronic ballast"  (aka switch mode power supply) in my now-disassembled bench lamp.  It arrived tonight and, indeed, it would be an easy replacement. It even came with clips to hold the light in the fixture.

This is what I was talking about before. No matter WHAT LED light source you use, you WILL have to build your own nice, quiet, resistor-ballast linear power supply for it. There pretty much is NO SUCH THING as a "quiet" LED power supply; the entire industry, and all the specialty silicon that has evolved around it, is based on modular CC buck converters using PWM regulation. Don't send it back; gut it and do the job you know you need to do anyways. 

mnem
"Don't turn it on; take it apart!"

* worsthorse hangs his head in shame

I know, I know. I was being hopeful and lazy (note the statement in my original post, I took the easy route, knowing there was a low probability of success). If it worked, problem solved, and on to something more interesting. Plus amazon returns.  The light I bought is glued together; getting to the supply will destroy the case, which is the reason I decided to try it.  So now to order something with a supply I can easily remove or to build something from scratch.

edit: that said, the sheer level of RF noise this particular LED supply put out was quite impressive. i've seen noisy LED supplies but nothing quite like this. it was worth trying it out just to see how bad it could get.

Yeah, I hear ya; it's a PITA of multiple flavors. Either the PITA of figuring out mounting hardware (already done with the T9 blub) or the PITA of disassembly so you can can mod it. The PITA of building a civilized power supply for it is of course just the chocolatey coating on top of that PITA... 

In ALL HONESTY... to me it's not worth the hassle unless you're retrofitting a swingarm magnifier; for "just a light" I'd scour eBay for a decent old swingarm lamp and put a nice, quiet 70w Halogen blub in it. 

mnem

[mnementh]

Is this junk or not?

   https://www.hozan.co.jp/E/catalog/Tweezers/P-831.html

Most probably, yes it's junk. I have a similar one that's NFG. I've come to the conclusion that none of these suction pick devices work unless they are connected to a proper vacuum line or a venturi suction generator on an air line.

Yes... it is. On second look, I had to modify my original "Ehhh... it's a parts picker" response:

BELAY THAT. IT'S JUNK.  Looking again, I see it has the same fatal flaw as the old squeeze-bulb models had: the middle part of the body is rubber, which will flex and cause the business end to move as you squeeze to release the part. Run, don't walk, in the opposite direction of ANY parts picker that doesn't have a single-piece solid body.

Agreed that only a real, active-vacuum parts picker works RIGHT; especially for repetitive production work... but for general one-off rework, I've had good success with the cheapies that have a bladder inside of a metal tube like this: Yes, they will leak down, especially on rough-surface parts. But you usually have plenty of time to get the part in place before they do.

mnem
*suckage*

[med6753]

I hate xMas...   

Zucca is DEFINITELY on the naughty list.

mnem
(Attachment Link)

Put me on that naughty list too. Humbug! 

[Specmaster]

I'd call it a good price - but I wouldn't go so far as to say it was a bargain.  Maybe I'm just too cheap - a criticism which I am prepared to admit.

Anyway, it would have been a far higher spec'd unit than my needs demand at this time - and the foreseeable future.

Nothing wrong in being a cheapskate if you can afford to wait awhile you'll get what you want. Was there a specific function on that 34401A that you wanted that don't appear on other 6.5 digit meters? There are often 6.5 digit meters on evil bay for far less than that.

[Specmaster]

Soldering naked is just plain crazy!

And not an image I want to see. 

   PAY. A. TTENTION!

mnem
Situational Awareness, yo.

In a Christmas Carolly fashion "Chestnuts roasting near a heavy load"  

[Cubdriver]

but med, when did low bandwidth specs, busted connectors, missing parts, and mechanical rebuild requirements ever put you off from buying a scope?   

Never...always up to the challenge.  Just simply helping a fellow TE nut (and boy does he need help). 

And no, I'm not interested in it. 

I think most of us here are well beyond help!

-Pat

[bd139]

Completely!

Just got all the bits to build myself a nice 200W HF dummy load today. This consists of four 50W Caddock thin film resistors, a big ass heatsink and two fans. Will 3D print a fan housing for it. Doesn’t go above 14MHz or so thus I’m not too bothered about construction with this.

Has a 40dB tap and I’m throwing my W7ZOI power meter in a hammond box with meter on it. Photos coming soon 

Edit: 50W not 30W resistors.

Edit 2: quick picture of unfinished item so far



Edit 3: can't moan at the meters. I got two of them for £1 each!

[worsthorse]

Yeah, I hear ya; it's a PITA of multiple flavors. Either the PITA of figuring out mounting hardware (already done with the T9 blub) or the PITA of disassembly so you can can mod it. The PITA of building a civilized power supply for it is of course just the chocolatey coating on top of that PITA... 

In ALL HONESTY... to me it's not worth the hassle unless you're retrofitting a swingarm magnifier; for "just a light" I'd scour eBay for a decent old swingarm lamp and put a nice, quiet 70w Halogen blub in it. 

mnem

Unfortunately, this little experiment demonstrates why trying to use an amateur band radio in my dense urban neighborhood is increasingly frustrating.  My neighbors, wishing to save money and do their bit to fight climate change are installing lights like the one I just tested in bulb and ring and strip form by the hundreds. The street lights are LEDs. The stop lights are LEDs. And every single one of them has a noisy, unfiltered and unshielded SMPS built into them, adding to the background noise level. It is a losing battle. I imagine that, in another four or five years, the bands under 30MHz will be unusable.

It is a lot like what's happened to the night sky in so many of my favorite haunts over the last twenty years and it makes me sad.

[beanflying]

I'd call it a good price - but I wouldn't go so far as to say it was a bargain.  Maybe I'm just too cheap - a criticism which I am prepared to admit.

Anyway, it would have been a far higher spec'd unit than my needs demand at this time - and the foreseeable future.

Nothing wrong in being a cheapskate if you can afford to wait awhile you'll get what you want. Was there a specific function on that 34401A that you wanted that don't appear on other 6.5 digit meters? There are often 6.5 digit meters on evil bay for far less than that.

Need had little to do with it  Casual mention of a 6.5 digit meter by @Brumby so I helped out with evilbay foo 

Reasonable price for what seemed a fully working meter with no testing in particular in Oz.