Test Equipment Anonymous (TEA) group therapy thread

[nixiefreqq]

damn dragon ..... he asked an innocent question about my k20 hp5280 and almost drove me nuts for a week.

he wanted to know what the thumbwheels did.  well they set the gate time in uSec.  but then i discovered that the MSD thumbwheel did not work. 

tracked it to a dead 1820-0732 on the option board.  what is an 1820-0732?  since i don't have a manual for the k20 and can't  find the pin outs for the IC on the interweb.....who the fuck knows what it really is?

did some tracing on the board and snooped around with a scope and decided it is a preset counter (set to be a down counter it turns out....well yeah....that is only logical after you noodle it out).  ordered a down counter and worked up a three IC replacement for the one mystery chip.  (ugly as a dog turd, but it works)

sucess!  here you see it counting a 1 Mhz signal from an 8640b with the gate time set for 456789 uSec.

I can almost smell the dog turd.     J/K....that's a nifty fix. 

And I see you use TinyCAD too. I just knew for some reason I liked you. 

yep.  tinycad is sure not the full blown autocad we had at work.  but it does the job for simple projects.

[mnementh]

(Attachment Link)    https://antiqueradios.com/forums/viewtopic.php?f=8&t=177192

Don't git any on ya. 

mnem
I don't always put something down here.

Another mass shooting in your neck of the woods then, must be the heat that's cooking everyone's brain, bet you're real glad to be getting the hell  out of Tejas eh?

Not a minute too soon. A homicide at our local Kroger last year was the polarizing event for my wife and myself; then the drive-by at our local Wally World about a year ago in which a 7-year-old girl was killed. Then of course El Paso and a dozen or so "smaller" Houston-area shootings in which "only" 2-4 were killed. We won't talk about things like Sandra Bland and the fact that Houston has the highest incidence of Police shootings of unarmed civilians in a state already drowning in idiot-cowboys-with-a-badge.  Also the highest incidence of collateral injuries; proving not only do they have shit judgement, they're lousy shots too. 

But hey... they're REAL GOOD at standing around and looking officious.  Just look at any accident scene... you can usually see two or three of them; chests puffed out under that 10-gallon trooper hat and them Ray-Bans with fists on their hips... instead of you know, directing traffic so there isn't a traffic incident as a result of the incident. 

Short version... you can't even feel safe in the presence of those sworn "to protect and serve" down here. They're as likely to kill you as the domestic terrorists. 

damn dragon ..... he asked an innocent question about my k20 hp5280 and almost drove me nuts for a week.

he wanted to know what the thumbwheels did.  well they set the gate time in uSec.  but then i discovered that the MSD thumbwheel did not work. 

tracked it to a dead 1820-0732 on the option board.  what is an 1820-0732?  since i don't have a manual for the k20 and can't  find the pin outs for the IC on the interweb.....who the fuck knows what it really is?

did some tracing on the board and snooped around with a scope and decided it is a preset counter (set to be a down counter it turns out....well yeah....that is only logical after you noodle it out).  ordered a down counter and worked up a three IC replacement for the one mystery chip.  (ugly as a dog turd, but it works)

success!  here you see it counting a 1 Mhz signal from an 8640b with the gate time set for 456789 uSec. 

Ummm... glad to be of service...?    Awesome bit of reverse-engineering, BTW. Thanks for blaming me! 

mnem
"That little droid's gonna cause me a lot of trouble..."
"Oh, he excels at that, sir."

[mnementh]

just noticed i have two stars and stripes.

hmmmmm.  wonder if the dragon has one with stars and stripes and one with a maple leaf?

Not YET, dammit...    But the OINP just opened up again, so our immigration is finally moving forward. Lets hope we can get in on the first round of filings.

mnem
*dwagon fingers, toes, wings and tail crossed for good luck*

[Cubdriver]

Nice haul, wch.  I got a pair of 8443As in a lot I snagged a few years ago.  Haven't opened one up as they seem to work (the counter part, anyway), and I haven't had time to poke and prod.  Nice, solid seeming instruments for sure.



-Pat

I haven't done much with mine either, other than power it up and have a quick look inside.



A 1MHz Ovenaire crystal oscillator is squeezed in at the back.

David

I powered mine up yesterday. The counter doesn't light up, though the power light and fan come on, so this one needs some work. Trouble is, I have to buy an entire HP spectrum analyzer to test the damn thing.  I can't see that happening.  Well, I can see that happening but I am going to try and resist. 

I know from experience that the counter section at least will function stand-alone (I don't have a spec an to go with mine yet, either, and haven't really been searching so far). In the photo, it's simply being fed by the signal generator below it.

-Pat

[BU508A]

Not YET, dammit...    But the OINP just opened up again, so our immigration is finally moving forward. Lets hope we can get in on the first round of filings.

mnem
*dwagon fingers, toes, wings and tail crossed for good luck*

Make sure, that when you are going to Canada to wear this:



Chances are good then that you could become the first RCMP Dragon.   

[med6753]

Not YET, dammit...    But the OINP just opened up again, so our immigration is finally moving forward. Lets hope we can get in on the first round of filings.

mnem
*dwagon fingers, toes, wings and tail crossed for good luck*

Make sure, that when you are going to Canada to wear this:



Chances are good then that you could become the first RCMP Dragon.   

And look like this........

[bd139]

If you can't get one of them there's plan B 

[med6753]

What the hell is that? Captain Canuck? 

[PA0PBZ]

Here's my vote:

[bd139]

I think PA0PBZ is the winner 

[worsthorse]

I finished the fluke and keithley this morning and they've both had their glamour shots:





They've had a rough-and-ready voltage and current adjustment, all the stickers and goo cleaned off, and the odd missing screw replaced. They pass the DMMCheckPlus test.  I listed them on CL this morning and will put them up here, too, later today.  (Yes, I am still an ebay seller virgin. No, I am not going to give that up quite yet.  )

I started working on the BK 2831D and discovered there wasn't a service, calibration, or schematics in the instruction manual. Nothing on the web either. Or at least for me to find. Anyone here know if any of this stuff exists? I will call the company on Monday but I am not optimistic.

After the 2831D I will work on the Keithley 199, which I know has an issue or two. Then there's the HP RMS voltmeters, of which there are three or so.

[factory]

well......except that the hp mystery part has 20 pins, and 74ls190 has 16.

also spent a lot of time trying to find some other hp gear that used an 1820-0732....... with no success.

at least it was possible to figure out some of the pin outs.  but the extra pins that are tied to either +5 or gnd are still unknown.

they might be to configure it as up or down.  or maybe for some other purpose.

I looked up the 1820-0732 at the time I posted about the K20-5280A (quote below), I couldn't find anything in the cross reference lists or that 1970's price list that are on the web either, it's used on the main up/down counter/display board too. Well done for creating a replacement for the option board. 

David

There is space on the main counter & display board for an extra Nixie, but I suspect that finding an extra 20pin 1820-0732 up/down counter IC would be impossible, given that I can't find anything about it, or any other TE that uses it. 

[Specmaster]

@mnem you don't hear anything like that happening in Canada, are guns not allowed there or are they just more civilised[emoji4]

Sent from my POT-LX1 using Tapatalk

[factory]

Nice haul, wch.  I got a pair of 8443As in a lot I snagged a few years ago.  Haven't opened one up as they seem to work (the counter part, anyway), and I haven't had time to poke and prod.  Nice, solid seeming instruments for sure.



-Pat

I haven't done much with mine either, other than power it up and have a quick look inside.



A 1MHz Ovenaire crystal oscillator is squeezed in at the back.

David

I powered mine up yesterday. The counter doesn't light up, though the power light and fan come on, so this one needs some work. Trouble is, I have to buy an entire HP spectrum analyzer to test the damn thing.  I can't see that happening.  Well, I can see that happening but I am going to try and resist. 

I know from experience that the counter section at least will function stand-alone (I don't have a spec an to go with mine yet, either, and haven't really been searching so far). In the photo, it's simply being fed by the signal generator below it.

-Pat

@wch Is the power supply faulty or is it stuck in standby mode?

Have either of you got the interconnect cable for the SA? Mine came with one but the seller munted them a bit as they couldn't be bothered to figure out how to remove/unclip it. They also broke one of the riv-nuts for the rear feet on the 141T SA display.   


The 8552A/8553B plug-ins for the display have blown fuses, I should probably fit some new ones as I couldn't find anything obviously shorted, I seem to remember one of the controls is seized too.
The display was tested with some scope plug-ins (1402A, 1421A) & works fine, all PSU voltages good, clean inside too. 


David

[Kosmic]

I was lucky this week and won some stuff at the government surplus auctions. Look like I was the only one bidding and got most of that stuff for pocket changes.



After disassembling the 3 Tek custom main-frame plugins, Got plenty RF parts to play with 

[mnementh]

@mnem you don't hear anything like that happening in Canada, are guns not allowed there or are they just more civilised[emoji4]

Mostly the latter. There are still lots of places up there where the local color comes big, brown & hungry. With teeth and clawed paws as big as your head.

Make sure, that when you are going to Canada to wear this:  Chances are good then that you could become the first RCMP Dragon.   

And look like this........    

Maybe as the MOUNT...    Naaahhh... I'd probably get kicked out, Just like Dudley and his horse did; I eat my peas with a knife.   

Here's my vote:

I'm not violent enough for hockey; this dwagon has mellowed in his old age.  But I'd still totes carry a hockey stick; Just like Harry Dresden. 'nuther good reason to move to Canada, eh?

If you can't get one of them there's plan B 

What the hell is that? Captain Canuck? 

I could totes be Captain Canuck-Dwagon:

"Now there, young man... put that firearm away..."

"What the fuck are you talking, ya crazy lizard...?!?" *KA-BLAM!!!*

*Ptoooie* *Ping* "Enough with all the noise, ya hoser... and would ya lay off the foul language, ehh?"

FUCK YOOOOOUUUU!!!" *KA-BLAM-BLAM-BLAM-BLAM-BLAM-!!!* click-click-click* 
*FWOOOOOOOOOM!!* *Sweeps up the ashes, because he is a civilized dwagon*

mnem
"I eat my peas with honey; I've done it all my life. I know it may sound funny, but it keeps them on my knife."   };=)~~~~<

[Kosmic]

@mnem you don't hear anything like that happening in Canada, are guns not allowed there or are they just more civilised[emoji4]

Sent from my POT-LX1 using Tapatalk

Lots of restriction on guns here. The only thing you can get easily (need to do a 2 days training session) is hunting rifle and shotgun. Side arms are heavily restricted (police screening, can only be used at a shooting range). Automatic weapons are forbidden.

[Vgkid]

That 7704a was sold , crisis averted.
Still need to clean the garage, and build a shop.

[Kosmic]

success!  here you see it counting a 1 Mhz signal from an 8640b with the gate time set for 456789 uSec.

Nice fix, good job !

[bd139]

Penis fingers strikes again. Breadboarding accident. Building an internal power supply for my Williams pulser because I can't find the other one I made in the junk boxes. However this is my last LT1073's switch pin...



So need to work out how to screw 90V or so out of something else I have lying around . Don't think I even have any switcher ICs left at all.

Edit: haven't even got any MOSFETs which I can bodge stuff with

Edit: I WILL NOT BE DEFEATED. How not to build a boost converter: on a breadboard with a 555 and a random MOSFET I found in the junk box an IRF620 ... but it works  . Feedback loop is via shorting the control pin to ground crudely with a 2n3904 and a voltage divider. Had to futz with it for a while to get the conduction cycle right for the pikey inductor. Doesn't need heat sink now due to thing bouncing an amp during conduction 

[worsthorse]

@wch Is the power supply faulty or is it stuck in standby mode?

Have either of you got the interconnect cable for the SA? Mine came with one but the seller munted them a bit as they couldn't be bothered to figure out how to remove/unclip it. They also broke one of the riv-nuts for the rear feet on the 141T SA display.   

David

I don't know if the PSU is bad or if it is stuck in standby mode. The standby light isn't lit with the power switch in either position.  I don't have the interconnect cable either.  But then I don't have the rest of the spectrum analzyer this is designed to go with, so it doesn't matter much. 

I do wonder if there is any way to trick the generator into putting out an RF signal without the SA and at some point I will crack the case open to see if I have a PSU problem or something else. It is a low priority project, though, given the other TE in the queue.

[Mr. Scram]

The ease with which you seem to whip up these circuits never ceases to amaze me bd139.

[bd139]

Probably that half a bottle of wine I drank before doing this  . Actually it has been a dick to get this one going as it's a bit of a hack job. The main thing with these is they are unconditionally stable at the cost of being noisy as hell and inefficient. It drinks 40mA doing nothing.

Anyway, got it wired up to the pulse generator and get 1.65ns rise time out of the 475 (around 210MHz) which is about right. Job done.

Turns out the transistor I had (an SGS 2n2369 out of a telequipment scope) doesn't avalanche until it hits around 120V which is annoyingly way above spec. Might try a 2n3904 in there tomorrow.



Annoyingly I was about to boot the 475 out but the dude who was going to buy it has disappeared off the face of the planet suddenly so might as well have some fun while it's sitting here doing diddly squat.

Think I might need a 2465B now 

Edit: DS1054Z (no fancy screenshot as I've lost my USB stick for it):



DS1054Z has trouble making rise time measurements without averaging on really fast signals. Have turned it on here but was reporting around 1.3ns rise time which is a bit high for a 100MHz scope!

[BU508A]

Penis fingers strikes again. Breadboarding accident. Building an internal power supply for my Williams pulser because I can't find the other one I made in the junk boxes. However this is my last LT1073's switch pin...



So need to work out how to screw 90V or so out of something else I have lying around . Don't think I even have any switcher ICs left at all.

Edit: haven't even got any MOSFETs which I can bodge stuff with

Edit: I WILL NOT BE DEFEATED. How not to build a boost converter: on a breadboard with a 555 and a random MOSFET I found in the junk box an IRF620 ... but it works  . Feedback loop is via shorting the control pin to ground crudely with a 2n3904 and a voltage divider. Had to futz with it for a while to get the conduction cycle right for the pikey inductor. Doesn't need heat sink now due to thing bouncing an amp during conduction 

This thing produces 135V very efficiently:



Source:
http://www.nixiekits.eu/service.php

The .pdf for the Nixietherm Mk III, Assembly manual:
http://www.nixiekits.eu/Downloads/NT_MkIII_Aufbauanleitung_Bausatz.pdf

[mnementh]

Penis fingers strikes again. Breadboarding accident....      Edit: I WILL NOT BE DEFEATED. How not to build a boost converter: on a breadboard with a 555 and a random MOSFET I found in the junk box an IRF620 ... but it works  . Feedback loop is via shorting the control pin to ground crudely with a 2n3904 and a voltage divider. Had to futz with it for a while to get the conduction cycle right for the pikey inductor. Doesn't need heat sink now due to thing bouncing an amp during conduction 

      

Looks at bd's circuit... looks at the MkII... Looks again...



mnem