Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Well done sir, that is an elegant solution and it looks a good trace as well. And yes, that bored, although I do have a project in the shape of a musical keyboard that I could be getting on with apart from the fact that once it's on my bench, will mean that I cannot get out of my lab easily, and since my boy dislocated his knee cap, he is stuck with crutches as he cannot put any weight on that leg due to it still being very swollen and painful so he spends his time on sofa.  I have to be able to go and attend to his requirements until he can dispense with the crutches hence, my boredom with not being able to repair the keyboard and the lack of anything smaller on Ebay etc to whet my appetite apart from the calculator to add to my collection of them 

[med6753]

LOL. That bored?

More 2225 pictures.

Pot has been modified. I had to file a flat on either side of the thread so it'd kit in the keyed hole. Now it's a 6mm shaft. Dug in the junk box and found an old 6.35mm coupling. Fits snugly behind the input board. Winner winner chicken dinner:





Total cost for repair £0!

Celebrating with a curry. I'll beat the dents out of the case tomorrow and reassemble it. No RIFAs either!

Good deal. Now you have ONE working analog scope. 

[bd139]

Well done sir, that is an elegant solution and it looks a good trace as well. And yes, that bored, although I do have a project in the shape of a musical keyboard that I could be getting on with apart from the fact that once it's on my bench, will mean that I cannot get out of my lab easily, and since my boy dislocated his knee cap, he is stuck with crutches as he cannot put any weight on that leg due to it still being very swollen and painful so he spends his time on sofa.  I have to be able to go and attend to his requirements until he can dispense with the crutches hence, my boredom with not being able to repair the keyboard and the lack of anything smaller on Ebay etc to whet my appetite apart from the calculator to add to my collection of them 

Gah been there. I was running once and stepped on a Thames Water drain cover and it went through. I symapthise with him! Hurts like f**k. My ankle and knee were like giant blueberries. They paid up a reasonable amount of compensation however when asked by my solicitor 

Know what you mean with the keyboards. I have one in the back of the cupboard. There's nowhere to put the damn thing in here. That's another thing from the era of TDS210 class LCD screens that need some work. I've been trying to grab one off ebay for about 3 years unsuccessfully.

Good deal. Now you have ONE working analog scope. 

  ... that's 50% of my scopes working now. That's a win!

[med6753]

Working on the Tek 2430 from yesterday. The fail I posted yesterday indicated a problem trying to verify the calibration of channel 1. I drilled down on the header fail and that's exactly what it was complaining about. After RTFM decided I might want to try a “Cold Start” first. It's a drastic measure that resets the DAC's and a bunch of other stuff and you risk losing cal data. Decided to go for broke anyway. But first I had to find and remove the jumper that allows you to perform that sequence. The manual offers no pictorial as to where it is and it took me over a half hour to find it.

See it? It's almost under the ribbon cable and that black block just below the “D”.



Once I removed the jumper was able to do a “Cold Start”.  All kinds of relays clicking and clacking and almost a blank screen when done. Not good. Powered off and back up. Now taking a NVRAM checksum error. Oh boy. But not surprised because it basically did a wipe. RTFM stated several power cycles should clear it but the calibration constants might be corrupted. Did that several times and the checksum error cleared but now had a new fail.

Drilling down on this fail stated that the Channel 1 and 2 attenuators needed an external calibration.



Did the external cal. Was very simple. Apply .2VDC, then 2.0VDC, then 20.0VDC to both channels. Did that and it passed. But then the Trigger failed stated it needed an external cal. Both external trigger inputs required 0VDC, .5VDC, and 2.0VDC.

Done and holy shit. My stumbling and fumbling around fixed the damn thing. It's now working great. And waveform amplitude and frequency appear to be dead nuts. I will never be able to repeat that.       

[factory]

*Passes the Stick of Enlightenment on to beanflying*

"Use it wisely, my son. Use it often and without hesitation; wherever it is most needed."

Hmmm. Apparently you don't need to explicitly copyright a media work in order to be able to extract royalties. I'm going to be rich at this rate

*Arrrou?!?* I know where I snurched this pic from... was that YOUR auction all those years ago?

As for it being the "Stick of Wisdom" or "Stick of Enlightenment"... to my knowledge, that was a term coined years decades ago inside HP; I think Rick Jones was one of the originators thereof...?

We referred to them as "pit props".

I don't know (or can't remember) an auction, but here's a picture of it in its current location (just NW of the centre of the picture).

Might have been this auction from a year ago;

https://www.ebay.co.uk/itm/Hewlett-Packard-19511-80014-legendary-034-HP-Attitude-Adjustor-034-or-034-HP-Pit-Prop-034-/222905807792?ul_noapp=true&nma=true&si=75UDVi1n2V%252Fh4qK9aHF7ne0EAwI%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557



David

[factory]

On tants, some of them are pretty reliable in the Tek scopes. Ones to watch out for are:
(SNIP)
3. Tubular wet tantalum. Usually Sprague 150D 109D. Occasionally one will just explode just to make your day shitty.

Corrected that for you, 150D are the hermetically sealed solid-electrolyte type.
https://www.vishay.com/docs/40015/150d.pdf

David

[beanflying]

Need more power for Beans  And yes it will glow under high load, LED high flow fans coming to compete with the Disco Green Fans on my Electronic Load 

   

No Fans, No Heatsink paste, time to break out 60A supply  51C on the body of the 4 in series/parallel so I think it will cope will plenty more than spec with fans under it if needed. On the numbers should be 2.5  measured 2.498  I can live with that 

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 

[beanflying]

Bean, my concern about this is that there would appear to be a total lack of airflow through the heatsink stack, raising the heatsinks of the face of the enclosure would greatly enhance the overall efficiency and capability of as a load..

Hmmm... sitting here munching on a couple of well buttered hot cross buns 

Fans going in under the heatsinks drawing air from the back.

I should make some Hot Cross Buns to have with Coffee but CBF for a small batch. 

[worsthorse]

Well that was fun.

Bodged the pot in loose to start with just to check it worked.


Bingo!

nice and crisp as well. Need to modify the pot slightly to get it in the hole. Will do that this evening.

nicely done, that. hope that means the money pit is small and shallow this time out.

[worsthorse]

Done and holy shit. My stumbling and fumbling around fixed the damn thing. It's now working great. And waveform amplitude and frequency appear to be dead nuts. I will never be able to repeat that.       

This is clearly TEA GND (good news day)... nice work.   

And while I was staring at that photo, I got to thinking... the first and last bezel buttons on the 2215 i bought are, ummm, unresponsive. the three middle buttons seem to work as expected. this scope is number three or four on the repair stack but i might as well as, if you have any suggestions on possible causes.

[neo]

Would you lot consider it related if i built a tube pre-amp just so i could actually use some of my equipment?

[Neomys Sapiens]

Ooh hot cross buns. Added to tomorrow’s shopping list now 

I'm gonna put all you guys on ignore if you don't quit talking about bread.  I can't have any and I'm jealous. 

Bacon....YES. Bread.....NO 

Given the country in which you live, that may be a not-so-big loss. Imagine you would live over here.
We do not allow 'byproducts of wood' in our bread.

When I had been in the US for a month, the first shop I went for when back and out of the airport was a bakery.

[bd139]

Would you lot consider it related if i built a tube pre-amp just so i could actually use some of my equipment?

90% of what I create is just justification to buy test gear. Amateur radio looked interesting because I could play with cooler toys than before. 

On the 2225 I’ve done a full functional check out and it’s working perfectly. The timebase calibration is out and the high frequency compensation needs some work but it’s a winner. Super happy with that.

[mnementh]

LOL. That bored?   More 2225 pictures. Pot has been modified. I had to file a flat on either side of the thread so it'd kit in the keyed hole. Now it's a 6mm shaft. Dug in the junk box and found an old 6.35mm coupling. Fits snugly behind the input board. Winner winner chicken dinner:

      Total cost for repair £0!

Celebrating with a curry. I'll beat the dents out of the case tomorrow and reassemble it. No RIFAs either!

Good deal. Now you have ONE working analog scope. 

   *Snicker-snort @ med-the-agitator* @bd: Well and truly Macgyver-fied!!!    

   *Passes the Stick of Enlightenment on to beanflying*

"Use it wisely, my son. Use it often and without hesitation; wherever it is most needed."

Hmmm. Apparently you don't need to explicitly copyright a media work in order to be able to extract royalties. I'm going to be rich at this rate

*Arrrou?!?* I know where I snurched this pic from... was that YOUR auction all those years ago?

As for it being the "Stick of Wisdom" or "Stick of Enlightenment"... to my knowledge, that was a term coined years decades ago inside HP; I think Rick Jones was one of the originators thereof...?

We referred to them as "pit props".      I don't know (or can't remember) an auction, but here's a picture of it in its current location (just NW of the centre of the picture).

Might have been this auction from a year ago;

https://www.ebay.co.uk/itm/Hewlett-Packard-19511-80014-legendary-034-HP-Attitude-Adjustor-034-or-034-HP-Pit-Prop-034-/222905807792?ul_noapp=true&nma=true&si=75UDVi1n2V%252Fh4qK9aHF7ne0EAwI%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557



David

That was the auction, for sure... but definitely several years ago since I saw it; I was still living in San Antonio.

Look at the date... I think this fellow runs it every year as an April Fool's gag.    We should watch for it, and pool our money to buy it and blow his mind! 

mnem
 

[neo]

Would you lot consider it related if i built a tube pre-amp just so i could actually use some of my equipment?

90% of what I create is just justification to buy test gear. Amateur radio looked interesting because I could play with cooler toys than before. 

On the 2225 I’ve done a full functional check out and it’s working perfectly. The timebase calibration is out and the high frequency compensation needs some work but it’s a winner. Super happy with that.

This was just an excuse to screw around with what i already have.







I shan't show the undercarriage, 'tis a crime against humanity. But this is the first project of mine that works as intended. All thanks to tautech, that magic eye is stage two.

[tggzzz]

Ooh hot cross buns. Added to tomorrow’s shopping list now 

I'm gonna put all you guys on ignore if you don't quit talking about bread.  I can't have any and I'm jealous. 

Bacon....YES. Bread.....NO 

Given the country in which you live, that may be a not-so-big loss. Imagine you would live over here.
We do not allow 'byproducts of wood' in our bread.

When I had been in the US for a month, the first shop I went for when back and out of the airport was a bakery.

Many people, myself included, have gone up nto a US supemarket, picked up a loaf  - and found our hand flying upwards. Why? Because the loaf is so light and full of air.

But there are places in the US where you can buy bread, and usually you can buy beer as well. Just not many places.

[nixiefreqq]

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!

[med6753]

This is clearly TEA GND (good news day)... nice work.   

And while I was staring at that photo, I got to thinking... the first and last bezel buttons on the 2215 i bought are, ummm, unresponsive. the three middle buttons seem to work as expected. this scope is number three or four on the repair stack but i might as well as, if you have any suggestions on possible causes.

The buttons might have slipped out of place or the bezel isn't fully seated. I had to pull the bezel on this 2430 to clean the screen because it was so dusty that it appeared the trace was out of focus. You have to be careful that those buttons don't shift. And once you pull the bezel you can check the film contacts to see if they work. Dunno about the 2215 but getting the bezel off this 2430 was rather easy. I only had to pull the intensity knob. The entire panel on the right side remains in place. That's a separate piece.

[tautech]

I shan't show the undercarriage, 'tis a crime against humanity. But this is the first project of mine that works as intended. All thanks to tautech, that magic eye is stage two.

Ya got it yet ?

[Specmaster]

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 

[0culus]

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 

[worsthorse]

This is clearly TEA GND (good news day)... nice work.   

And while I was staring at that photo, I got to thinking... the first and last bezel buttons on the 2215 i bought are, ummm, unresponsive. the three middle buttons seem to work as expected. this scope is number three or four on the repair stack but i might as well as, if you have any suggestions on possible causes.

The buttons might have slipped out of place or the bezel isn't fully seated. I had to pull the bezel on this 2430 to clean the screen because it was so dusty that it appeared the trace was out of focus. You have to be careful that those buttons don't shift. And once you pull the bezel you can check the film contacts to see if they work. Dunno about the 2215 but getting the bezel off this 2430 was rather easy. I only had to pull the intensity knob. The entire panel on the right side remains in place. That's a separate piece.

All noted. Thanks. I haven't dug into the service manual yet, though if I freak out when I open the 475A, I may end up working on this one first. 

[nixiefreqq]

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)

[0culus]

Never let the facts get in the way of a good story! 

In other news, I reached a deal to keep the 8664a and get the refund I wanted. I've satisfied myself that it's working fine and is worth repairing the cosmetic damage, with a new pair of rack handles. I'll probably look into replacing the RF output if need be.

[Cubdriver]

Never let the facts get in the way of a good story! 

In other news, I reached a deal to keep the 8664a and get the refund I wanted. I've satisfied myself that it's working fine and is worth repairing the cosmetic damage, with a new pair of rack handles. I'll probably look into replacing the RF output if need be.

Excellent news!

-Pat