Test Equipment Anonymous (TEA) group therapy thread

[Cubdriver]

Well, I now have two HP 6722B power supplies in unknown operational condition (one allegedly powers up at least), along with a 6299A 0-100V jobbie listed as 'for parts' incoming from the 'bay.  Made offers on all three, and all were accepted. 

More for the repair stack.

Wowzers! Glad I'm not the only one who gets a little carried away with power supplies. I still don't know why it happens.

You're on a power trip?   

I have a bad habit of being 'inspired' by other's purchases.  Usually it's moderated a bit because the one they have gotten will have been the last cheap one, and all remaining will be priced by folks who've looked at the catalogs and want original list price for the battered, looks-like-it-was-dragged-to-the-bottom-of-the-Grand-Canyon-and-back-tied-behind-a-burro, badgeless, footless, cracked-knob, dented-case, gouged-panel POSs they've listed (untested, of course), and I'll say "meh - maybe in a few months" and promptly forget to add it to my terminally maxed out search list.  This time, though, there were two decent looking specimens in the sub c-note with shipping range, both with 'make an offer' options.  So I did.  Both accepted.  And while waiting to hear, I started looking at others, and wound up making an offer on the 'for parts' one, too.  And here we are.

My house is going to fall down one of these days...

-Pat

[Cubdriver]

I read the manuals to find more stuff to hunt down.  At least for the HP gear, simply look at the opening pages of the 'maintenance' section of the manual, and you should find a list of 'recommended' or (sometimes, even better) 'required' equipment to be used for calibration, troubleshooting and repair of your newly acquired piece of kit.  Determine what you may lack that is listed, and use this information to begin new evilBay quests for said missing instruments (each of which will ALSO have a service manual containing such a list, fodder for further searching, and so as the flea poem ends, "and so, ad infinitum").

(Or, if all that seems too much research, just get some old HP catalogs and start working your way through them, getting one of everything.)

-Pat

There is only one Reason I have a 419A the HP manual for the 740B told me one was needed 

That's fine, but have you gotten the gear needed to keep the 419A in good nick?  (It'll probably call for a 740B, so you'll need to get another one to use as a reference - can't go using the one you're 'checking' with the 419A to calibrate that same 419 A, now can you?  )   

-Pat

[worsthorse]

That's cool. Never knew about those codes.

Yeah, they are in the back of the manual. Took a bit to find them.

Most people don't even read manuals. I do, but not prior to (intent to) purchase. Doing so is dangerous.

So that's why I have had a rapid build up of Test Gear  I read spec. sheets carefully first, then look for a manual and gloss over it to at least make sure there is a better chance of repair if needed, then do a search to see if it is good or bad in general then punch the evilbay button after limited self justification of NEED to the collection 

There is no real consideration of budget or cost

I read the manuals to find more stuff to hunt down.  At least for the HP gear, simply look at the opening pages of the 'maintenance' section of the manual, and you should find a list of 'recommended' or (sometimes, even better) 'required' equipment to be used for calibration, troubleshooting and repair of your newly acquired piece of kit.  Determine what you may lack that is listed, and use this information to begin new evilBay quests for said missing instruments (each of which will ALSO have a service manual containing such a list, fodder for further searching, and so as the flea poem ends, "and so, ad infinitum").

(Or, if all that seems too much research, just get some old HP catalogs and start working your way through them, getting one of everything.)

-Pat

Reading this I thought... thank god it ain't just me.   Because I was doing exactly that this afternoon: looking at the required equipment list for calibrating the 8640B and saying to myself, okay, gotta get one of those. and one of those. and, oh hell, how have i survived without one of those?   

[mnementh]

mnem
 

[worsthorse]

my flourishing addiction to test gear is actually rooted in my already well-established addiction to building kits and homebrewing. i was reminded of the connection today when i started sorting through two cartons of kits i've ordered - but not yet built - over the last two years, which were covered over by three or four bags of random RF parts i've been acquiring for a series of nostalgia projects: a norcal40, a sierra wilderness transceiver, the R2pro, and a neophyte. 

and why haven't i built any of them? because, of course, i've been rehabbing test gear that i bought in support of my building habit.   

[beanflying]

Seems I need to buy a chart recorder  Not to mention a 738BR Multimeter Calibrator and a .......

[0culus]

Where do you draw the line and just send the damn thing off to a professional cal house? Particularly for standards.

In other news, I'm amusing myself by programming some "handy to have" things into the HP-15C, such as Vrms -> Vpp and Vpp -> Vrms.

[beanflying]

Where do you draw the line and just send the damn thing off to a professional cal house? Particularly for standards.

In other news, I'm amusing myself by programming some "handy to have" things into the HP-15C, such as Vrms -> Vpp and Vpp -> Vrms.

I am moving somewhat in that direction. I did mention it a while ago that I am looking at improving the accuracy of some Data Logging gear I have made in the past and then toward getting some of them made in small volume (generally industrial temperature logging). To improve that accuracy I need some sort of traceable reference which is why the 34401A and 34461A are having a $1k trip to Keysight.

This known then gets applied to the rest of the gear and brought close to Cal or if it can't be I will at least know not to use it or what the limits are. It will give me good certainty toward a few PPM which is better than I want or need to make by a factor of 10 if not 100.

Still well short of Cal Lab standards but I can give a proper spec to what I make or service and a stated accuracy and know it will be ok.

[VK5RC]

Had a successful TEA repair morning, the back up battery for the HP 8970A finally arrived.
You have to love the process of re-calibration of the IF attenuators, plug on a noise source, then hit "33.0 special function" wait 5 secs - that's it!
Also my 'new baby' transceiver, an Icom 7610, a software defined transceiver, has a tendency to drop off the adhesive taped on heat sinks on the ADCs! Which can go bouncing around shorting out other goodies, WA6JKN has very kindly made a small clip, laser cut, to hold them on. All installed today!
Rob

[VK5RC]

Re scrapping gear for parts, I am a true TEA, every time I tried, I ended up thinking - 'that unit is not too bad' - at one stage I had 4 Tek 453s! I am now down to 2, one 'museum' unit even with the cover, one fully working parts unit 'in case' - I know how bad I am!

[GregDunn]

Has anyone heard from Inverted18650 lately? Last week him and I were discussing meeting up either today (Friday) or tomorrow in PA. I sent him a PM this past Tuesday asking if this was still our plan. No response. And I haven't seen him on here either. I'm getting concerned that something has happen. I wish we had gotten to the point of exchanging cell numbers but we hadn't.

I hope he's OK. 

I last talked with him on the 19th. He had some doctor appointments coming up, so probably taking care of that stuff.

Mmm; yeah, I've sent email within the last couple of days and gotten no response either.     I know he has doctor appts, car repair and some general health issues to deal with, so I haven't been bugging him other than to just say "still here, how are you feeling" occasionally.

I do think I have his cell # somewhere, so if someone really needs to contact him I suppose I could share it privately.  I know he will check VM periodically.

[med6753]

Has anyone heard from Inverted18650 lately? Last week him and I were discussing meeting up either today (Friday) or tomorrow in PA. I sent him a PM this past Tuesday asking if this was still our plan. No response. And I haven't seen him on here either. I'm getting concerned that something has happen. I wish we had gotten to the point of exchanging cell numbers but we hadn't.

I hope he's OK. 

I last talked with him on the 19th. He had some doctor appointments coming up, so probably taking care of that stuff.

Mmm; yeah, I've sent email within the last couple of days and gotten no response either.     I know he has doctor appts, car repair and some general health issues to deal with, so I haven't been bugging him other than to just say "still here, how are you feeling" occasionally.

I do think I have his cell # somewhere, so if someone really needs to contact him I suppose I could share it privately.  I know he will check VM periodically.

Yes, I fully understand that he has several issues that absolutely takes priority over anything TEA which is why I haven't bugged him either except for the PM this week. And that's only because he said last week that we could tentatively meet up this week and I just wanted to confirm. We have been trying for over a month to arrange for the exchange of equipment and for various reasons it just hasn't happen. 

[kj7e]

I decided to dismantle the 6227B to pull and check the 1500uF 40v C1 caps.  At first I was cussing HP for how difficult there where to get to, until I realized the main and slave boards slide out the back, brilliant!

3 of the 4 main 3000uF 40v caps are very dead, one is just okay.  The 5uF C2 caps are also dead.  All of the other Electrolytic's tested somewhat okay, but just going to replace them all and not worry about them again, ever.





Usable;


Bad;


Just plain dead;


Somewhat okay;


Main board 325uF crowbar supply caps not bad at all;


Should be 5uF... Bad;

[Cubdriver]

Nice teardown!  What is the serial number prefix of the supply?  (first four digits)  I'm trying to date the caps, and it looks like 8434 for the big ones (34th week of 84), and maybe 8447 for the 1500uF one - can't quite make it out.  Though that seems old given the excellent condition of the supply - the s/n prefix would establish the earliest it could have been manufactured.  (And I like how you hide your vodka in plain sight on the bench in that innocent looking squeeze bottle... )

-Pat

[GregDunn]

Has anyone heard from Inverted18650 lately? Last week him and I were discussing meeting up either today (Friday) or tomorrow in PA. I sent him a PM this past Tuesday asking if this was still our plan. No response. And I haven't seen him on here either. I'm getting concerned that something has happen. I wish we had gotten to the point of exchanging cell numbers but we hadn't.

I hope he's OK. 

I last talked with him on the 19th. He had some doctor appointments coming up, so probably taking care of that stuff.

Mmm; yeah, I've sent email within the last couple of days and gotten no response either.     I know he has doctor appts, car repair and some general health issues to deal with, so I haven't been bugging him other than to just say "still here, how are you feeling" occasionally.

I do think I have his cell # somewhere, so if someone really needs to contact him I suppose I could share it privately.  I know he will check VM periodically.

Yes, I fully understand that he has several issues that absolutely takes priority over anything TEA which is why I haven't bugged him either except for the PM this week. And that's only because he said last week that we could tentatively meet up this week and I just wanted to confirm. We have been trying for over a month to arrange for the exchange of equipment and for various reasons it just hasn't happen.

Same here.  Hopefully he'll be back soon and in better health!

[PrecisionAnalytic]

Stepper motors from printers are A) not powerful enough (except to move a laser) to do anything useful and 2) always use some idiotic mounting system that does not play well with anything except molded plastic bosses and stamped sheet metal and Ω) almost globally use oddball windings that aren't compatible with any stepper driver that will play nicely with common ardu-based 3DP/CNC controllers.

I've done the "hackaday project" route... it's SO worth the ~$70 cost of entry for a modern MKS Gen board and NEMA 23 steppers. If you want to go absolutely balls & braces, a RAMPS 1.4 board can be had as cheap as $11 if you don't care about quiet steppers; and NEMA 17 for ~$7 each. But those will pretty much barely move a 300w router spindle in MDF.

And if you actually want to produce something... or if you just want to get to LEARNING sometime in the same week as you unpack the gear... starting with one of the popular 8020/4020 or better yet, OpenBuilds V-Slot Aluminum extrusion based kits is the way to get your feet wet. The 8020 frame takes 95% of "noob user error" out of the equation, as by default it makes the first, most important part[/b] of any 3DP/CNC build "trained ape easy":

"Build it rigid, flat and square, THEN add motors & electronics".

Just consider that $250-350 as your tuition; cost of entry. It really is the cheapest way to get into "learning mode" quickly, rather than spending days and weeks in "pulling your hair out" mode. The thing with all of this is that it's all "hobbyist" and "experimental" gear; it's not like a Craftsman table saw that comes with instructions and even a "User Guide" so you have some idea where to start. Most everything requires trawling the web and usergroups to get knowledge, then build your own instruction set that works for YOU.

Please... learn from my mistakes.  You will save yourself oodles... just oodles... of wasted time, money and aggravation. 

mnem


And if you know all this, just consider my post as a PSA for the next guy who doesn't. 

Good looking out.  Of course I have all the components from a few instructables examples for an Arduino build... interestingly enough Hackaday just posted a new article regarding, the one that inspired me to actually buy the components, what I thought I had saved all the files and article related though couldn't find and wound up downloading everything to mirror again. 

Damn... good save.  Yesterday or was it early this morning... I was looking at one of the recent instructables using the 80/20 construct of course also.

Yeah... technically... what I have saved and found is the heavier duty 4'x4' style plasma cutter I think someone in Austin made that I think would be a little more pain to setup... though way more versatile and heavy duty.  Schupan Boneyard material review time too.

I wound up tearing into a free 42" LG LED TV and found corrosion and vertical sections gone or haywire for a reason.  I'll still tear into the printers even to just post the modules on eBay to see if something sells.  Worked posting stuff on eBay last month... everything sold.  This month of course nothing sells. 

I've hesitated for years now regarding the CNC build and the mini-lathe with tapered bearings and some improvements so I can machine some discone and other antenna and maybe even other electronics system components seems more feasible as actually happening.  I'd like to modify the mini-lathe into a mill also. 

[beanflying]

CNC Routing is the problem child out of what you seem to want to get out of your potential playing. All the other options, Laser, Plasma?, 3DP are all light loads on the axis and belt drive is generally going to be fine with minimal backlash issues.

The Cheap 3020 Routers available from China are a good start point if you want to play with PCB type routing and light timber and plastics if you take it easy. Mine is is the 'Cupboard' waiting for me to get back to spending some time on it again. Brushless motor and improved motor mount are first (3D printed upgrades)

As mnementh suggested forget about the Printer bits you will finish up in a hole before you start. Underneath the partially stripped CR-10S printer (going into an enclosure) is my 1000x600 2.2kW CNC beasty that is due for rewiring and a dust hood to be made now the stupid of Summer is nearly over. It's wiring was done by a 'cabinet maker' 

[bd139]

Bored factor 9 Mr Sulu. Just bought another heathkit GDO with coils this time.

Felt like a restoration job is in order.

[factory]

Seems I need to buy a chart recorder  Not to mention a 738BR Multimeter Voltmeter Calibrator and a .......

Corrected that for you, the 738BR calibrator can only do DC volts or AC volts at 400Hz (rms or peak to peak), the voltage range is 3mV to 300V, not really a multimeter calibrator then.

I would add a picture of the front panel but I seem to have photographed everything apart from the outside and I can't get to it at the moment either.

Here are some pictures of the insides instead, I do have an untested rectifier bulb to replace the later resistor diode MOD bodge underneath (the serial number is in the range of the last ones to have had a hollow-state rectifier);

David

[factory]

Couple more pictures as I exceeded the max allowed in a post;

David

[bd139]

Bored factor 9 Mr Sulu. Just bought another heathkit GDO with coils this time.

Felt like a restoration job is in order.

Replying to myself here... GDO use, with some buggering around:

https://youtu.be/pZBuE63F1WI

[beanflying]

Seems I need to buy a chart recorder  Not to mention a 738BR Multimeter Voltmeter Calibrator and a .......

Corrected that for you, the 738BR calibrator can only do DC volts or AC volts at 400Hz (rms or peak to peak), the voltage range is 3mV to 300V, not really a multimeter calibrator then.

I would add a picture of the front panel but I seem to have photographed everything apart from the outside and I can't get to it at the moment either.

Here are some pictures of the insides instead, I do have an untested rectifier bulb to replace the later resistor diode MOD bodge underneath (the serial number is in the range of the last ones to have had a hollow-state rectifier);

David

Nice Pics  I can get by without the 738BR 'for now'. My Fluke 335D and Valhalla AC Calibrator will just have to do until I get the specified device

[factory]

Nice Pics  I can get by without the 738BR 'for now'. My Fluke 335D and Valhalla AC Calibrator will just have to do until I get the specified device

You've got me checking the lists now, just need that 740B, 5211A & the equivalent of the last four items on the list......   

David

[med6753]

Seems I need to buy a chart recorder  Not to mention a 738BR Multimeter Voltmeter Calibrator and a .......

Corrected that for you, the 738BR calibrator can only do DC volts or AC volts at 400Hz (rms or peak to peak), the voltage range is 3mV to 300V, not really a multimeter calibrator then.

I would add a picture of the front panel but I seem to have photographed everything apart from the outside and I can't get to it at the moment either.

Here are some pictures of the insides instead, I do have an untested rectifier bulb to replace the later resistor diode MOD bodge underneath (the serial number is in the range of the last ones to have had a hollow-state rectifier);

David

That Dale power resistor has seen A LOT of current and looks mighty crispy.  I would check that circuit for a partial short or some other reason for the excessive current.

[mnementh]

I decided to dismantle the 6227B to pull and check the 1500uF 40v C1 caps.  At first I was cussing HP for how difficult there where to get to, until I realized the main and slave boards slide out the back, brilliant!

3 of the 4 main 3000uF 40v caps are very dead, one is just okay.  The 5uF C2 caps are also dead.  All of the other Electrolytic's tested somewhat okay, but just going to replace them all and not worry about them again, ever.

      Usable;      Bad;      Just plain dead;      Somewhat okay;      Main board 325uF crowbar supply caps not bad at all;      Should be 5uF... Bad:   

Thanks for all the delicious analog power pr0n!!! 
Sorry to hear about all the bad caps though... that BOM is gonna be pretty pricey.  But EVERY bench should have at least ONE good linear supply for those occasions where switching noise/EMI fucks with the results; and that there is a damned fine example of linear power pulchritude. *SCHWAANNNNG!!!*   

Am I the only one here who's noticing how that seems to be more and more frequently? The demise of good older analog power like this... combined with just plain ignorance of the "analog domain" in general due to digital EVERYTHING... has really raised the noise floor in EVERY application.

I expect maybe there will be a resurgence in linear power sometime down the road... just like that guy who figured out how to make nixies from scratch.

mnem
"Sometimes newer is just newer... not better." ~granddad