Test Equipment Anonymous (TEA) group therapy thread

[tonyalbus]

Fun with flags DMMs
Amazing how fast that 34401A settles.

The Datron does still have that extra digit..
The Picotest 3500A is an Keithley 2100 if i am correct.

[cyclin_al]

And I see you have a secret stash of those little Tek toggle-switch caps. More than a few in here gonn' be a little jelly o' dat. 

That reminds me that I need to find some of those ... more time acquiring stuff instead of doing stuff 

[med6753]

The Type CA plug-in. See schematic. In order to achieve a good DC balance V3334 and V3354 are Tek matched pairs with special part numbers. I don't have that. One is a Tek P/N and the other is an unmatched 12AU6. Therefore I can't get an accurate DC balance. It's pretty sloppy. However, the gain and the compensation is excellent. I figure 2 out of 3 ain't bad. Can live with that. No more twiddling controls. It's done. 

[mnementh]

Would that part of the circuit be horribly difficult to convert to silicon? Seems might could be a lot less assache than trying to match random hollow-state...

mnem
 

[mnementh]

And I see you have a secret stash of those little Tek toggle-switch caps. More than a few in here gonn' be a little jelly o' dat. 

That reminds me that I need to find some of those ... more time acquiring stuff instead of doing stuff 

Yeah, IIRC there's a 3DP model listed in the feet and knobs thread. But as small as the part is, it will be very difficult to print with FDM so it doesn't just look like a blob of hot-gloo. Would def render better with SLA, but that will usually require painting to match other bits of the scope and...   

mnem
 

[BU508A]

The Type CA plug-in. See schematic. In order to achieve a good DC balance V3334 and V3354 are Tek matched pairs with special part numbers. I don't have that. One is a Tek P/N and the other is an unmatched 12AU6. Therefore I can't get an accurate DC balance. It's pretty sloppy. However, the gain and the compensation is excellent. I figure 2 out of 3 ain't bad. Can live with that. No more twiddling controls. It's done. 

Here is a matched pair with Tek part number for ca. 39 Euro:
https://www.ebay.com/itm/123904949153

[mnementh]

Oooh... the least assache solution of all. You enabler, you. 

mnem
It's only money.

[med6753]

The Type CA plug-in. See schematic. In order to achieve a good DC balance V3334 and V3354 are Tek matched pairs with special part numbers. I don't have that. One is a Tek P/N and the other is an unmatched 12AU6. Therefore I can't get an accurate DC balance. It's pretty sloppy. However, the gain and the compensation is excellent. I figure 2 out of 3 ain't bad. Can live with that. No more twiddling controls. It's done. 

Here is a matched pair with Tek part number for ca. 39 Euro:
https://www.ebay.com/itm/123904949153

Thanks for that but I'm going broke purchasing additional parts and I haven't even cracked open the two Type 547's yet.   

That will be Friday. Tomorrow is USA Thanksgiving and I'm spending the day with Son and grand kids. 

[mnementh]

Same here with dad.

Happy Thanksgiving one and all!

mnem
*sigh* still so much to be thankful for...

[ch_scr]

Today, literally Blinkenlights!
When recapping the PM6670, it occured to me I'd like the trigger indicator only the "higher end" PM6671 and PM6672 of that particular series have. The PCB's are all the same and I did have to take off the front panel to get to some 'lytics hiding behind it anway, so I drilled two holes and installed the LED's. Getting the knobs off to remove the panel is a chore, and worst case the LED's would have stayed dark forever. The additional circuitry needed is described in the service manual and on an option board anway. Today the PCB was milled and populated - but after putting it in, it did nothing
On the picture you can see Pin 16 of the IC where the copper is not cleared around it, the IC ground pin. While doing the layout  I planned to solder that leg to the top ground plane to also have a necessary ground connection below, saving a soldered wire via and making a more compact layout. But when soldering in the IC just now, somehow not soldering that lead on top, to have less hassle removing it again in case it would not work, seemed more appropriate
Thankfully it all came back to me after short confused probing around and staring at the PCB. It works now, but only up to ~15MHz. I think I might need a faster PNP transistor on there than that BC807 at hand - original used 2N5771

[bitseeker]

this is the most boat-anchory bit of TE I've acquired thus far. I've been on the casual lookout for one of these test sets, either an 8920 or 8924, for a while but they tend to be pricey. I finally came across this 8924C



It has a 6-Watt input, instead of the usual 3-Watt, but not the beefier 60- or 100-Watt. It does have the mechanical attenuator, which makes its calibrated bottom end 400 kHz instead of the 30 MHz of the ones with electronic attenuator.
...

If you have not bought the replacement bezel I have a spare you can have FOC.
Does t have the Spectrum Analyser fitted?

Hi Robert! I actually did purchase a bezel already (it's badged as an 8924E). If something happens to it on its way over here, or it turns out to look worse than I can tolerate , I'll let you know. Thanks for the offer!

Yes, the 8924C has the spectrum analyzer as default equipment. The only "problem" I ran into while verifying its operational condition was that it had been set up for CDMA operations, so some of the tests failed without the 83256B PCS interface. After reconfiguring it for regular analog operation, all was well. Having never used one of these before, it's been a bit of an adventure poking around all the menus and the built-in HP BASIC programs.

I take it you have seen this?
http://www.amtronix.com/poweron.htm

Ignore the 8924 manual and use the 8920B  manual.
I you want a copy of the RF Tools utility etc I have them on Flash card.
I passed my 8924C on to a friend just before Covid lockdown. I had picked up a very tidy 8920B cheap and have a R&S CMU-200 (Actually a CRTU-RU with CMU-200 software) so the 8924C was just taking up space. Still have some spare parts. If you ever need anything let me know. There is a small 8924C group on groups.io

Thanks, yes, I had come across it the day the 8924C arrived. I'll set mine up accordingly since I don't have use for the CDMA functionality. Amtronix also has a quick-start page (in serious need of some formatting): https://www.amtronix.com/8924cqs.htm

I haven't yet looked at what all the RF Tools consist of. Can they be extracted and then loaded into another flash card or into RAM?

Congrats on the 8920B deal. That's certainly easier to relocate than the 8924 behemoth with its "Two-person Lift" stickers on the sides.

[bitseeker]

Dana 5100 related.    Some parts for the PROM burner arrived along with other items. 

Had to laugh at the TFXTDOOL  zif sockets.   At $0.61 each I wasn't expecting much.  These met my expectations.  They only need to work a few times.  If they don't work at all, I will spend the £20+ for a genuine part.

Indeed. TFXTDOL sockets are a staple of the $10-20 component tester kit. They do work more than a few times and, for the price, you can have many spares.

[bitseeker]

Guys, do you have a Fluke 8840A, 8842A or 8842AF with a flakey VFD display? If so then you might find this link of interest, someone on the forum has developed a replacement LED display that is almost a drop-in replacement albeit with a few slight modifications. Fortunately, both of my displays are very good, I did have another that had a worn out module but I managed to flip that one.

https://www.eevblog.com/forum/testgear/fluke-884042-series-universal-replacement-display/new/#new

I like the IDEA of a dot-matrix display for these that one can customize fonts, notification shape/size/location etc... but honestly, I think that AHOL's blue LED "near drop-in" replacement is probably a better solution for most of us, especially if you provide it with a dedicated power source such that any concern of it excessively loading the meter's power supply is rendered moot. I also appreciate AHOL's dedication to customer service once problems were found. Here's the thread; I'll let y'all decide fer yerselves:



https://www.eevblog.com/forum/buysellwanted/ebay-led-display-module-fluke-8840a42a-(diy-kit)-replace-broken-damaged-vfd/

mnem
Also, a friendly      at Vince and his Jihad against blue LEDs; I quite like the 485nm blue ones AHOL chose. 

The custom LED display does look great and the color choice was good for the intended emulation. He really did a nice job. One good thing about the matrix-based display projects, though, is that you get more flexibility and you aren't limited to having every annunciator in a dedication location, but the low resolution isn't as cool looking.

[bitseeker]

Fun with flags DMMs

Amazing how fast that 34401A settles.

And how fast it boots, and the size of the digits (still doesn't beat the Datron, though). It's a great meter. I wouldn't part with mine, which is why I had to get a backup (an Agilent version ).

The Datron does still have that extra digit..

And the cool Panaplex display!

The Picotest 3500A is an Keithley 2100 if i am correct.

Sure looks like one. If it isn't one, it's a good design knockoff.

[ch_scr]

[...]
The Picotest 3500A is an Keithley 2100 if i am correct.

Sure looks like one. If it isn't one, it's a good design knockoff.

It's the other way around - the K2100 is a Picotest 3500A. Somehow Keithley decided selling the Picotest meter as "bottom of the barrel" for educational markets and to people that want a "cheap" meter that says Keithley. I think there was talk the Picotest was a bit too close to Keithley designs and that deal was the reparation? Not sure on that part of it. Bloody shame they skimped on the voltage reference in there, and the UI is lacking a bit. Once you are over that, not that bad a meter. There is a russian guy who put in a better reference and was quite happy with it afterwards.

Edit: See Kosmic below, Array M3500A is the original and Picotest and Keithley rebadge it.

[Saskia]

anybody out there in need of an Ender ? I might have a spare (in box, unused, currently in the moving pile, available when I dig it out ...)

[mnementh]

EVERYBODY needs at least one. Even med.

mnem
 

[Kosmic]

The Picotest 3500A is an Keithley 2100 if i am correct.

Apparently, the Picotest and Keithley are rebrand of the Array M3500a.

http://www.array.sh/M3500A.htm

https://www.eevblog.com/forum/testgear/m3500a-(picotest)/msg276677/#msg276677

[Neper]

Some key component in the heating system of the building has conked out, this morning. No heating, no hot water. Landlord says spare part should arrive by Monday. 

[mnementh]

Quick, everybody move into the landlord's house. 

mnem
"Expedited" says I.

[Cerebus]

I wouldn't touch it either... just in case it's been fuckerized by a gorilla and full of cesium dust and make you glow in the dark.

Even 60 years old that would still gonna be dangerous.

mnem
"...Must be these strangers that come every night;
Their saucer-shaped eyes put people uptight!
Leave little green footprints that glow in the dark;
I hope they get home all right. "

Please don't tell me that you think natural caesium is radioactive. Natural caesium is as un-radioactive as natural sodium and considerably less radioactive than natural potassium.

In terms of oridinary everyday toxicity, caesium is on a similar level to its alkali metal cousins sodium and potassium. Any caesium metal exposed to the air from a caesium beam tube would have oxidised in the same way, and with similar but more energetic enthusiasm, as any other alkali metal.

[mnementh]

Why would I expect caesium used in such a bit of test equipment to be in any way natural...? Why would I know any of this?

Not all of us were ever strong with the organic chemistry; so a honest thank you for the infodump. 

I'll still keep my distance; if anyone could find the one such unit that actually is somehow contaminated with radioactive material, it would be me and the "convergence of radical improbability" that is my life.

And quite frankly, nothing in your little demonstration there does anything to make me feel any less like keeping my distance. 

mnem
 

[dl6lr]

And I see you have a secret stash of those little Tek toggle-switch caps. More than a few in here gonn' be a little jelly o' dat. 

That reminds me that I need to find some of those ... more time acquiring stuff instead of doing stuff 

And now for an ad from our sponsors me: https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg3484004/#msg3484004

[tonyalbus]

The Picotest 3500A is an Keithley 2100 if i am correct.

Apparently, the Picotest and Keithley are rebrand of the Array M3500a.

http://www.array.sh/M3500A.htm

https://www.eevblog.com/forum/testgear/m3500a-(picotest)/msg276677/#msg276677

Thanks, that is some good information.
Yes i indeed noteced that it takes a long time to settle, just like the siglent, while the Brymen and 34401A where there very quick..
that is why i did the test.  (with my old keithley 199 i never noticed it took long, i wondered why the 3500 did, as is was keithley too.. now i know)
But it is nice to have as an extra.. it samples very fast like a keithey, it is running v3 or 3.1 if i remember correct one of the latest.

[bitseeker]

@Richard

I couldn't take it anymore and redid the Amtronix quick start guide for the 8924C. The formatting was just too horrendous and it was also in need of editing (consistency, spelling, grammar, etc.). So, I did. And while I was at it, I added in info from some of their other pages on the 8924C.

Note that I didn't compare the text with actual labels in the instrument or HP manuals. So, there may still be some errors in capitalization or abbreviations.

PDF attached.