Test Equipment Anonymous (TEA) group therapy thread

[malagas_on_fire]

I'm so pissed off with not having a new toy to play with that I have just pressed the button on a TI Nspire calculator, now to source some of the alternative keyboards for it.

Something that hasn't got yet fully touch or bezels to worry about when dropping . They will age and last years.

[bitseeker]

I bid on an auction I wasn't sure I actually wanted to win. Got outbid with stupid money. My conscience is at ease now.

Sometimes things just work themselves out.

[VK5RC]

"Plenty of fish in the sea"
MwaaaHaha. TEA enabler
Rob

[0culus]

Let's play a game of "guess the waveform!" 

[beanflying]

Labels 4 Mnementh including the point at which smoke may begin  . Mooning shot for Specmaster.

Short riser block/mount for the pair of fans to be made when they arrive.

[bitseeker]

Cool beans!

[Cubdriver]

Let's play a game of "guess the waveform!" 

Something amplitude modulated with three steps, and frequency modulated with a short pulse?

-Pat

[0culus]

Let's play a game of "guess the waveform!" 

Something amplitude modulated with three steps, and frequency modulated with a short pulse?

-Pat

Good guess!

Without giving it away too much, it's the analog waveform of a common digital logic construct.

[mnementh]

Hmmm?

o--3Ω--o--2Ω--o = 5Ω R¹
|                     |
o--4Ω--o--1Ω--o = 5Ω R²
|                     |
o                    o
+    Measure   -

R¹ x R²         25
---------   = ----- = 2.10Ω 2.5 Ω
R¹ + R²        10

Should yield 2.10Ω  Of course I'm just guessing at your layout; a legend on your panel would be nice for those of us playing along at home. 

mnem
Still crazy math-defective after all these years...

Arranged that way to allow 2x5Ω strings to maximize current under load so the 4Ω takes 50W of 125W @ circa 3.5A/String.

There will be Labels

Fair enough. Given the lack thereof, I could only make a best guess that you had them wired as they were laid out physically. 

Your attempts at load-leveling will of course fail miserably, resulting in one or more of them shifting higher when you are least prepared; but you knew that.

I'm so pissed off with not having a new toy to play with that I have just pressed the button on a TI Nspire calculator, now to source some of the alternative keyboards for it.

AND it has a proper = key!   well done spec!

Of course, don't want any of that RPN rubbish do we 

once mnem called me "the voice of reason and moderation" on this thread.

as such.... I will not comment further. (maybe he called me something else.....but my memories are my reality)

I believe my sentiment was more like "It's a sad day indeed when nixiefreqq is the voice of reason..."   But I do applaud your attempt, in this instance at least, to manifest a modicum of moderation.

mnem

[mnementh]

   
Labels 4 Mnementh including the point at which smoke may begin  . Mooning shot for Specmaster.

Short riser block/mount for the pair of fans to be made when they arrive.

So, gonna mount the fans push/pull through the stack, or did you actually drill holes in the base of that lovely casting?

Still not too late to make it all horizontal to fit on a shelf... Then you'd have room for a panel meter. I do sincerely wish you luck not smoking it, however...  all this tinkery does make my experiments with soggy coils of coathanger seem much less unreasonable, doesn't it?

mnem
Actually, those LED ballast resistors are pretty robust; they'll take quite a pounding. But I know from experience that this fact invites abuse. 

[0culus]

So I found a listing on Amazon for a copy of the HP-15C advanced functions handbook from a third party...good price so I bought it. Lo and behold I get another copy of the regular user manual that has a sticker on the back calling it the advanced functions manual.  I figure I'll keep it though, as it's a later printing than the one I got with the calculator and might have errata corrected.

Yeah, I have the PDF version, but holding the nice little wire bound book is nicer. Now back to square one to find a print version...

[beanflying]

So, gonna mount the fans push/pull through the stack, or did you actually drill holes in the base of that lovely casting?

Still not too late to make it all horizontal to fit on a shelf... Then you'd have room for a panel meter. I do sincerely wish you luck not smoking it, however...  all this tinkery does make my experiments with soggy coils of coathanger seem much less unreasonable, doesn't it?

mnem
Actually, those LED ballast resistors are pretty robust; they'll take quite a pounding. But I know from experience that this fact invites abuse. 

As this thread shows time and again Hot Air Rises  so pushing through the Heatsink. I haven't Swiss cheesed the lower case yet but I an leaning toward making a 3D printed Grill to keep it looking nice and just take out most of the rear wall as an inlet.

[med6753]

So, gonna mount the fans push/pull through the stack, or did you actually drill holes in the base of that lovely casting?

Still not too late to make it all horizontal to fit on a shelf... Then you'd have room for a panel meter. I do sincerely wish you luck not smoking it, however...  all this tinkery does make my experiments with soggy coils of coathanger seem much less unreasonable, doesn't it?

mnem
Actually, those LED ballast resistors are pretty robust; they'll take quite a pounding. But I know from experience that this fact invites abuse. 

As this thread shows time and again Hot Air Rises  so pushing through the Heatsink. I haven't Swiss cheesed the lower case yet but I an leaning toward making a 3D printed Grill to keep it looking nice and just take out most of the rear wall as an inlet.

Let it burn. 

[PrecisionAnalytic]

I never remember to check for hamfests around me and have not ever gone to one.   

I haven't yet either.  I'm lately addicted to Craigslist, Offerup, Letgo and online free searching or other searches for specific items I'm looking for as a fix.

Especially using Google and the search term with the "site:whateversite.org" syntax after the search term with or without parenthesis.

[PrecisionAnalytic]

I spent a couple of hours building the TM500 extender kit and tomorrow will resume working my way through the pile of plug-ins I've acquired over the last couple of months. It will be such a pleasure to not have to work on stuff while it is in the frame.

I'm anticipating building and extender for the Pacific Measurements D14(A) modules..., and wound up updating the JAMMA wikipedia entry since my JAMMA Connector proposal draft was suggested to merge with the JAMMA wiki..., so I have some reference information and figured others can use a reference.  Kind of a tangent... though why not.  Threw in the RJ21 link while at it on the wiki.   

https://en.wikipedia.org/wiki/Japan_Amusement_Machine_and_Marketing_Association

Then bought more Pacific Measurements modules (H13, x2 V12's, N10), some detectors and the D14A.  Next I'm going to read into sometime if I can figure out how to make the detectors for less than the cost of purchasing.

I'm not sure how else to work on the modules without extenders.  Figured the same for the Tektronix 7000 series.

[med6753]

I'm not sure how else to work on the modules without extenders.  Figured the same for the Tektronix 7000 series.

I've been able to calibrate and adjust the attenuators on 7000 series vertical plug-ins on a 7603N by simply removing the scope's side cover and leaving the mesh screen off the plug-in. This may not be sufficient if you have to troubleshoot the plug-in because you can't get to the backside of the circuit board but for routine maintenance it works. The timebase plug-ins are more complex and an extender is almost mandatory but luckily they require less maintenance. 

[tautech]

I'm not sure how else to work on the modules without extenders.  Figured the same for the Tektronix 7000 series.

I've been able to calibrate and adjust the attenuators on 7000 series vertical plug-ins on a 7603N by simply removing the scope's side cover and leaving the mesh screen off the plug-in.

Yep that's how you do the plugins on the Telequipment D83 also.

This may not be sufficient if you have to troubleshoot the plug-in because you can't get to the backside of the circuit board but for routine maintenance it works. The timebase plug-ins are more complex and an extender is almost mandatory but luckily they require less maintenance.

They ain't hard to make.
Below from another recent thread. IIRC I just drew the etch resist on with a ruler and permanent marker and notched it to maintain polarity like the notches in the plugin cards.

Make one, the hardest part is finding the right socket.
For the rest some old PC IDE ribbon cable and the for the plug just etch some strips on a PCB.
You could probably just do the strips with a Dremel.


One I made moons ago for the plugins for a UK Telequipment D83 (owned by Tek).

[Specmaster]

Labels 4 Mnementh including the point at which smoke may begin  . Mooning shot for Specmaster.

Short riser block/mount for the pair of fans to be made when they arrive.

That's a good mooning shot, good air flow assured [emoji16]

[Specmaster]

So I found a listing on Amazon for a copy of the HP-15C advanced functions handbook from a third party...good price so I bought it. Lo and behold I get another copy of the regular user manual that has a sticker on the back calling it the advanced functions manual.  I figure I'll keep it though, as it's a later printing than the one I got with the calculator and might have errata corrected.

Yeah, I have the PDF version, but holding the nice little wire bound book is nicer. Now back to square one to find a print version...

Print it in book format and then spiral bound it, the bits are on ebay etc. [emoji48]

[med6753]

I'm not sure how else to work on the modules without extenders.  Figured the same for the Tektronix 7000 series.

I've been able to calibrate and adjust the attenuators on 7000 series vertical plug-ins on a 7603N by simply removing the scope's side cover and leaving the mesh screen off the plug-in.

Yep that's how you do the plugins on the Telequipment D83 also.

This may not be sufficient if you have to troubleshoot the plug-in because you can't get to the backside of the circuit board but for routine maintenance it works. The timebase plug-ins are more complex and an extender is almost mandatory but luckily they require less maintenance.

They ain't hard to make.
Below from another recent thread. IIRC I just drew the etch resist on with a ruler and permanent marker and notched it to maintain polarity like the notches in the plugin cards.

Make one, the hardest part is finding the right socket.
For the rest some old PC IDE ribbon cable and the for the plug just etch some strips on a PCB.
You could probably just do the strips with a Dremel.


One I made moons ago for the plugins for a UK Telequipment D83 (owned by Tek).

But doesn't that cause roll off in the vertical response at high frequencies? I would think that 50Mhz and above could be problematic. 

[bd139]

It would do. Most of the time you use these while they are broken.

Or when I did some cal, pull it out then adjust it and stick it back in again. Took a few times.

[med6753]

It seems that the "Cold Start" I performed on this 2430 DSO had other positive benefits. I noticed that the GPIB now shows status although I don't use it. And prior to the cold start when the scope was powered off upon power up would default to CH1, 100mV, 100uS. Now it does a much preferred remembers last settings when powered up. There's probably a bunch of other things that got reset that I just haven't discovered yet. 

[tautech]

The D83 I built if for was a just a 50 MHz CRO. 

Wasn't so worried about any top end performance impacts only the ability to get to any test point I wanted to.
With CRO's, most often so few real adjustments are needed once the PSU is to spec and faults are fixed.

[beanflying]

Randomly I was watching this TonyG Video a couple of days ago about extender cards

https://youtu.be/9DN74VX37O4

[VK5RC]

I thought I would show my rough dc loads, used to proof test a 28V 35A linear PSU, it powered my 1.2GHz 350W PA for EME.
I didn't run them for too long as everything gets very hot esp me!
So close to b-f design but mine are much rougher I am afraid.

Edit re the HP extender boards in the video above - I have bought some of the kits - very useful, I found the best way to coat the tips in solder was to put solder on then drag it off with solder wick and a good hot iron.