Test Equipment Anonymous (TEA) group therapy thread

[neo]

I can guarantee you the pixies inside a CRT are NOT happy... that ain't love they are spewing at the screen. 

Also with my 2, 209A VTVMs both now work with the exception of AC and lack of dead on accuracy. One is more accurate than the other, but to be fair the other is older and was in much worse shape. 
One worked when i got, got complete cap replacement have not checked resistors.
The other was DOA, which coincided with just how trashed the thing was. Replaced caps, but no resistors, turned it on annddd... nothing... Alot of head scratching later i discovered the (hand wound) resistor inside the meter was bad, replaced it with an approximate value. Works fine.

Swapped the meters both to satisfy an obsessive tick as well as to test the broken one in known working circuit

The AC probes though present don't seem to see any voltage i put something on them and it doesn't matter if it is .1 or 1 it reads the same.   

I'm considering fitting them with new banana plug sockets instead of the pins, you know so they can look more useful while sitting on that top shelf.  But also because one still has the old DC probe connector, might actually be more useful if i didn't need a broken probe to interface with it.

I may adjust them eventually but for now i am getting tired of screwing with them.

Also fixed lately, my Fairchild 7050A whose only problem was so simple i didn't believe it and went through the thing before accepting it really could be that simple. A single dead transistor, now replaced and ready for the next 50 years of regulating.   I seem to be oddly good at procrastination, even going so far as being useful while i'm at it.

EDIT: With the ac probes i found the problem, how foolish of me to assume the metal case with a connection through the cord was ground. 

Does anyone find this the least bit interesting?

[beanflying]

Does anyone find this the least bit interesting?

Like my random decent into TEA'dom from a day or two back random ramblings on random subjects are well RANDOM. 

[neo]

Does anyone find this the least bit interesting?

Like my random decent into TEA'dom from a day or two back random ramblings on random subjects are well RANDOM. 

You do have a point but random ramblings CAN be amusing, even interesting. Certainly with what could easily be the world's largest VTVM.

[beanflying]

Much as I love this thread and those who hang out here some of the content is deserving of it's own thread as here bounces RANDOMLY all over the place. Threads like this lose valuable content like the link to the HP cross reference I posted yesterday because I didn't know of the thread Tautech reposted it in.

The milling of Custom Power supply cases is thread worthy IMO without the electronics inside. So start a DIY enclosure thread? Absolutely not to say don't post it but perhaps make it stand alone?

There is pages on the Quicko soldering station that to filter through this thread would be                 

[neo]

Much as I love this thread and those who hang out here some of the content is deserving of it's own thread as here bounces RANDOMLY all over the place. Threads like this lose valuable content like the link to the HP cross reference I posted yesterday because I didn't know of the thread Tautech reposted it in.

The milling of Custom Power supply cases is thread worthy IMO without the electronics inside. So start a DIY enclosure thread? Absolutely not to say don't post it but perhaps make it stand alone?

There is pages on the Quicko soldering station that to filter through this thread would be                 

I guess the way it works is that the regulators and curators here filter through the content and if deserving of it's own or a different thread then they help put it there. Of course the answer could just as easily be, why did the chicken cross the road? 

[beanflying]

Because the chicken had no idea what it was doing 

Random cleanup shot. Left over knobs I brought at a junk Aiction aged 12'ish for $1 

TEA related I have now stacked my soldering stations to save horizontal space 

[neo]

I just did the math and, counting non-functional units, i have 15 multimeters.
Working;
3, bench* LCD
1, bench LED
1, bench Nixie
1, rack-mount LED
2, rack-mount Nixie
2, VTVM
1, hand-held VOM
Non-Working,
1, bench Nixie
2, bench LED
1, VTVM

*1: Bench here defined as a unit in a case not more than half a rack wide
*2: Not counting beyond all hope units.


No problems here.

[tautech]

Much as I love this thread and those who hang out here some of the content is deserving of it's own thread as here bounces RANDOMLY all over the place. Threads like this lose valuable content like the link to the HP cross reference I posted yesterday because I didn't know of the thread Tautech reposted it in.

Then it's a good thing some are keeping an eye on precedings here ! 

That's precisely why I started that thread and in short time it got sticky'ed due to its value.
The various 'net search engines can mostly find what you seek if you're inventive enough with keywords but some of the archives never show up in searches and you have to go and check through then each. 

Sphere are pretty good for HP and Tek stuff and the X ref pages hold all manner of links, some of which they ask not to be linked for fear of download traffic so we just point ppl to their site.
Have a look around:
http://www.sphere.bc.ca/

[Specmaster]

I can guarantee you the pixies inside a CRT are NOT happy... that ain't love they are spewing at the screen. 

Also with my 2, 209A VTVMs both now work with the exception of AC and lack of dead on accuracy. One is more accurate than the other, but to be fair the other is older and was in much worse shape. 
One worked when i got, got complete cap replacement have not checked resistors.
The other was DOA, which coincided with just how trashed the thing was. Replaced caps, but no resistors, turned it on annddd... nothing... Alot of head scratching later i discovered the (hand wound) resistor inside the meter was bad, replaced it with an approximate value. Works fine.

Swapped the meters both to satisfy an obsessive tick as well as to test the broken one in known working circuit

The AC probes though present don't seem to see any voltage i put something on them and it doesn't matter if it is .1 or 1 it reads the same.   

I'm considering fitting them with new banana plug sockets instead of the pins, you know so they can look more useful while sitting on that top shelf.  But also because one still has the old DC probe connector, might actually be more useful if i didn't need a broken probe to interface with it.

I may adjust them eventually but for now i am getting tired of screwing with them.

Also fixed lately, my Fairchild 7050A whose only problem was so simple i didn't believe it and went through the thing before accepting it really could be that simple. A single dead transistor, now replaced and ready for the next 50 years of regulating.   I seem to be oddly good at procrastination, even going so far as being useful while i'm at it.

EDIT: With the ac probes i found the problem, how foolish of me to assume the metal case with a connection through the cord was ground. 

Does anyone find this the least bit interesting?

Hell yes I find this all interesting, some of it makes me chuckle nicely to myself (otherwise family think I'm going mad, or am I already?).

I'm just waiting for that slow boat from China to bloody dock with my parts so I can back onto something interesting and more meaningful, but in the meantime I always enjoying your entries [emoji5]

[neo]

Hell yes I find this all interesting, some of it makes me chuckle nicely to myself (otherwise family think I'm going mad, or am I already?).

I'm just waiting for that slow boat from China to bloody dock with my parts so I can back onto something interesting and more meaningful, but in the meantime I always enjoying your entries [emoji5]

Thank you, i'm tempted to take a go at fixing my 608C. Only two reasons I've not tried is that
A) all i know about vacuums tubes is this, Is it glowing? Is it meant to? 
B) last time i moved all 100+ pounds of this monster i nearly broke both my legs and an arm. Heavy bastard let me tell you....

It should be a interesting journey to get that thing working, to say the least. Maybe i will get lucky and have it be simple though given the symptoms i doubt it.

[Specmaster]

Hell yes I find this all interesting, some of it makes me chuckle nicely to myself (otherwise family think I'm going mad, or am I already?).

I'm just waiting for that slow boat from China to bloody dock with my parts so I can back onto something interesting and more meaningful, but in the meantime I always enjoying your entries [emoji5]

Thank you, i'm tempted to take a go at fixing my 608C. Only two reasons I've not tried is that
A) all i know about vacuums tubes is this, Is it glowing? Is it meant to? 
B) last time i moved all 100+ pounds of this monster i nearly broke both my legs and an arm. Heavy bastard let me tell you....

It should be a interesting journey to get that thing working, to say the least. Maybe i will get lucky and have it be simple though given the symptoms i doubt it.

WTF is this 608C then that it weighs much?

[neo]

Hell yes I find this all interesting, some of it makes me chuckle nicely to myself (otherwise family think I'm going mad, or am I already?).

I'm just waiting for that slow boat from China to bloody dock with my parts so I can back onto something interesting and more meaningful, but in the meantime I always enjoying your entries [emoji5]

Thank you, i'm tempted to take a go at fixing my 608C. Only two reasons I've not tried is that
A) all i know about vacuums tubes is this, Is it glowing? Is it meant to? 
B) last time i moved all 100+ pounds of this monster i nearly broke both my legs and an arm. Heavy bastard let me tell you....

It should be a interesting journey to get that thing working, to say the least. Maybe i will get lucky and have it be simple though given the symptoms i doubt it.

WTF is this 608C then that it weighs much?

HP 608C VHF generator, as stated vacuum tubed and it goes to 480MHz on paper, though when i tested it went straight to 500 megahertz seemingly without issue. A real HP beauty i got for free. 

Now the issue, no output now, even when there was output the meters on it were screwy and it's missing a big knob. Last seen costing 40 dollars, though the shaft is so big this is a mere annoyance.

EDIT: Of note this thing is 18.5 inches deep and 8U tall, that is 14 inches. It's the rarer rack mount version.

[bd139]

Chinese New Year over with 

Just got about ten aliexpress dispatch notices 

Still no sign of my other T12.

[BravoV]

I suggest using carbon fiber rod as a pushrod to actuate a remote ratcheting switch. You've got plenty of room beside the panel meters to install like a 3-5mm rod, and they're cheap.

I'd suggest not. The great advantage of remote mains switch pushrods (ala HP) is keeping the nasty high voltage angry pixies well away from the fingers. The great disadvantage of carbon fibre rod is that it's conductive or rather its conductivity is very poorly controlled and the one thing it most definitely is not is an insulator. Glass filled nylon rod or some other reliable insulator would be a better pick.

Is there any "other" advantages, apart from angry pixies ? 

Say like to reduce noise, magnetic interference and etc ?
As some T&M layout design, the sensitive analog part are mostly placed near front panel.

Example the black rod (at the scope) or the green ones (LCR) here. (click to expand photos)

[nixiefreqq]

wow!

a live 608c!

good luck with that baby.   at work they almost always had a "two man lift" warning stencil on them (and for good reason). 

once saw a guy at the old gaithersburg fest with a couple dozen of them stacked 3 high in a wall.  by noon he was begging folks to just take a couple for free so he did not have to re-load them for a trip to the dump. 

felt like a wimp.....but turned and walked away.   never saw them show up in quantity again so he probably kept his word.

now days an 8640b feels heavy.

good luck with it.  someday you may have the only one still in captivity.

[Cerebus]

Is there any "other" advantages, apart from angry pixies ? 

Say like to reduce noise, magnetic interference and etc ?
As some T&M layout design, the sensitive analog part are mostly placed near front panel.

Example the black rod (at the scope) or the green ones (LCR) here. (click to expand photos)

Generally the idea is to keep the angry pixies in a nice little coral, usually in the back left hand corner of the PCB. All the other goodies tend to flow naturally from doing that one thing, such as:

• Not dragging long mains traces along the edge of the board where they just invite clumsy fingers when you've got an instrument open for fault finding or adjustment.
• Minimising loop area of mains traces.
• As you say, maximising separation and isolation from signal paths.
• Meeting safety requirements - insulation, separation and all that good stuff.
• Easy to put a metal fence around them, for safety or signal integrity reasons.
• Far away from the 'coffee spilling' or '500 pound gorilla' end of the instrument.

• Probably 17 other good reasons I've forgotten.

[mnementh]

Does anyone find this the least bit interesting?

Like my random decent into TEA'dom from a day or two back random ramblings on random subjects are well RANDOM. 

You do have a point but random ramblings CAN be amusing, even interesting. Certainly with what could easily be the world's largest VTVM.

Speaking as someone who has moderated over 3 decades on USEnet, IRC, Groups, FB, and dozens of private forums devoted to various tech, hobbyist and entertainment subjects, one thing I've found is that a broad tolerance for OT, Stream of Consciousness, and Following Tangents type content are absolutely critical to keeping a forum alive, and serve to make that forum interesting long after the titular subject matter has been well used up and core content has been repeated so many times that the regulars know it by rote.

Allowing a long leash while still maintaining a zero-tolerance for hatefulness, personal attack and trolling is what makes folks feel at home, so they feel like they can be themselves, and that is what makes them willing to share knowledge, insights, humor and expertise gained over a lifetime. This is what makes for a rich experience that rewards the reader and makes them want to join in, and that is how you feed the living, breathing entity that is any good forum.

Much as I love this thread and those who hang out here some of the content is deserving of it's own thread as here bounces RANDOMLY all over the place. Threads like this lose valuable content like the link to the HP cross reference I posted yesterday because I didn't know of the thread Tautech reposted it in.

Then it's a good thing some are keeping an eye on precedings here ! 

That's precisely why I started that thread and in short time it got sticky'ed due to its value.
The various 'net search engines can mostly find what you seek if you're inventive enough with keywords but some of the archives never show up in searches and you have to go and check through then each. 

Sphere are pretty good for HP and Tek stuff and the X ref pages hold all manner of links, some of which they ask not to be linked for fear of download traffic so we just point ppl to their site.
Have a look around:
http://www.sphere.bc.ca/

Curating and moderating a thread is the other half of keeping it alive; this needs people like you who are genuinely interested in the subject matter, and who have a lot of patience.

Thank you, and all those like you, who take on this daunting task.  I know from personal experience just how huge the personal expenditure involved can be. I also know how rewarding it can be, but this kind of reward requires a certain breed of err... eccentricity to fully appreciate. 

I suggest using carbon fiber rod as a pushrod to actuate a remote ratcheting switch. You've got plenty of room beside the panel meters to install like a 3-5mm rod, and they're cheap.

I'd suggest not. The great advantage of remote mains switch pushrods (ala HP) is keeping the nasty high voltage angry pixies well away from the fingers. The great disadvantage of carbon fibre rod is that it's conductive or rather its conductivity is very poorly controlled and the one thing it most definitely is not is an insulator. Glass filled nylon rod or some other reliable insulator would be a better pick.

Is there any "other" advantages, apart from angry pixies ? 

Say like to reduce noise, magnetic interference and etc ?
As some T&M layout design, the sensitive analog part are mostly placed near front panel.

Example the black rod (at the scope) or the green ones (LCR) here. (click to expand photos)

Those rods are glass-impregnated resin or glass-filled nylon, and their design is to (a) be insulative/non-inductive and (2) be rigid as possible, so that your tactile experience is as close to directly actuating the switch as possible.

The latter is why I recommended CF or Al rod, because either would serve well in this vein. Fiberglas rod would also serve similarly, though is (a) not as rigid for any given diameter as CF, (b) is much harder to cut cleanly, and (3) does not  yield a finished end product that is nearly as attractive or "finished" looking as is possible with CF or Al.

The primary engineering principle behind it is to keep all the noisy, rambunctious pixies from the AC line voltage through to the high-voltage rectification and HF switching in a SMPS in their own little corner at the back of the device, as far away as possible from sensitive low-level circuits and high-voltage intolerant human fingers.

In hindsight, I'd say the best mix of the above for Chris' project would probably be an oversized 'glas rod with a machined Al button at each end connected to a remote switch; this would be a lot of work, but Chris has already shown that he's not averse to machining like a madman.


Cheers,


mnem
*Long ago gone 'round the South Bend* (machinist humor)

[bd139]

Sunday afternoon test gear hack. Been making some again.

Wasn't too happy with the power meter I made the other day so I made another one. It's Sunday and I'm impatient so screw waiting for OSHpark or anyone to make a board for me. And I don't want to sit in front of the computer so I did it old style. In the interest of not drilling any fucking holes (I hate that side of the work), I did the whole thing SMD with an etch resist pen by hand .  Turned out pretty good.



Most of the parts are actually recycled from the HP 54602B (RIP!) motherboard I have in the cupboard, leaving only a couple of resistors, capacitors and another AD8307 out of the new parts stock. The soul of the machine shall live on.

This is whacked into an arduino pro mini. I'm not using it as an Arduino, just a canned AVR target I don't have to solder up - directly via AVR-GCC + USPasp programmer taped to the board as you can see plugged into and a shitty chinese LCD. A far nicer one is arriving on Tuesday. You can get the arudino, USPasp and LCD for under a tenner delivered to the door in the UK from bitsbox.co.uk

You power it up, apply 0dBm, press the button, then apply -20dBm (or stick an attenuator in line) and it auto calibrates itself. To recal, you hold down the button for 10 seconds. Calibration constants are stored in EEPROM (or will be once I've wired up that code ). 

[ChrisLX200]

I'll figure something out for the rod and there is an internal divider plate the rod can pass through for added stiffness.

First, find a suitable switch. I ordered some of these: https://www.ebay.co.uk/itm/5-Pcs-KDC-Series-DPST-Latching-Push-Button-Power-Switch-250V-AC-8A/291554946491?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 It should be easy to mate the end of the rod to the switch, and a push button for the front is no trouble to make.

Mains supply is 'rated' at 800w (LOL) so I assume something like 400w output is more likely without the thing melting. Not sure how well two DC-DC PCBs are going to perform when being fed by a single 48v output of the mains PSU. If it hangs together then two channels with max 200w output each, in a very compact layout (5" square, 14" long), is a good addition to my gear. I don't have a lot of space so this would be ideal - and why I'm building it of course..

[tggzzz]

The great advantage of remote mains switch pushrods (ala HP) is keeping the nasty high voltage angry pixies well away from the fingers.

So, what do you make of pixies at -2kV on front panel potentiometers - operating in the rain, after being submerged 3ft underwater?

While I love my sweet little 1502 dearly, and used it at a hamfest today to check cables, I have no intention of getting it wet!

[tggzzz]

In the interest of not drilling any fucking holes (I hate that side of the work), I did the whole thing SMD with an etch resist pen by hand .  Turned out pretty good.

Wow! You actually got one of those wretched pens things to work!

Personally I prefer stanley knifing or dremeling the slots out.

[bd139]

In the interest of not drilling any fucking holes (I hate that side of the work), I did the whole thing SMD with an etch resist pen by hand .  Turned out pretty good.

Wow! You actually got one of those wretched pens things to work!

Personally I prefer stanley knifing or dremeling the slots out.

They’re pretty easy when you know a couple of tricks. Firstly don’t buy an etch resist pen. Second is buy a staedtler lumocolor, fine, blue. Then clean the board properly, scrub it with a kitchen scourer to rough it up, don’t touch it at all, draw PCB out, use wife’s hair dryer to bake it for a couple of minutes, then go over it again, then bake it, then etch it in hot ferric chloride (none of that fancy new shit) and you’re done.

Board turnaround is about 30 minutes.

Knifing and dremeling is too imprecise I found. Plus it’s quite difficult.

[Cubdriver]

wow!

a live 608c!

good luck with that baby.   at work they almost always had a "two man lift" warning stencil on them (and for good reason). 

once saw a guy at the old gaithersburg fest with a couple dozen of them stacked 3 high in a wall.  by noon he was begging folks to just take a couple for free so he did not have to re-load them for a trip to the dump. 

felt like a wimp.....but turned and walked away.   never saw them show up in quantity again so he probably kept his word.

now days an 8640b feels heavy.

good luck with it.  someday you may have the only one still in captivity.

I don't have a C, but just took a look and there are two Ds and an E in my various piles.  Does that count for anything?   

-Pat

[Specmaster]

wow!

a live 608c!

good luck with that baby.   at work they almost always had a "two man lift" warning stencil on them (and for good reason). 

once saw a guy at the old gaithersburg fest with a couple dozen of them stacked 3 high in a wall.  by noon he was begging folks to just take a couple for free so he did not have to re-load them for a trip to the dump. 

felt like a wimp.....but turned and walked away.   never saw them show up in quantity again so he probably kept his word.

now days an 8640b feels heavy.

good luck with it.  someday you may have the only one still in captivity.

I don't have a C, but just took a look and there are two Ds and an E in my various piles.  Does that count for anything?   

-Pat

Sure do, it means that you have a lower grade pass and almost failed 

[neo]

wow!

a live 608c!

good luck with that baby.   at work they almost always had a "two man lift" warning stencil on them (and for good reason). 

once saw a guy at the old gaithersburg fest with a couple dozen of them stacked 3 high in a wall.  by noon he was begging folks to just take a couple for free so he did not have to re-load them for a trip to the dump. 

felt like a wimp.....but turned and walked away.   never saw them show up in quantity again so he probably kept his word.

now days an 8640b feels heavy.

good luck with it.  someday you may have the only one still in captivity.

I don't have a C, but just took a look and there are two Ds and an E in my various piles.  Does that count for anything?   

-Pat

Sure do, it means that you have a lower grade pass and almost failed 

So the 608C is now rare? Neat.

EDIT to add: Pat, as I'm sure you already know the 608D & 608E are upgraded versions of this one. At least they are meant to be.