That's what I get for thinking.
I like to let my Bling hang out that and I brought a heap of those Rose cases for very few $. As it is only 10
![Ohms \$\Omega\$](https://www.eevblog.com/forum/Smileys/default/omega.gif)
maximum it will never have more than 17V across it so I wasn't worried about exposed joints etc either, was more about keeping it cool if I wanted to load up right up.
Well Tek 2225 arrived. Well packaged. Excellent condition. I am surprised. Focus is as expected, knackered but I can get a line with some careful tweaking and the rest of the scope seems fine. Woohoo.
Time to crack it open!
Edit: cracking it open appears to be more difficult than expected as there’s a dink in the side which means the cover won’t slide off.
That's what I get for thinking.
I like to let my Bling hang out that and I brought a heap of those Rose cases for very few $. As it is only 10
maximum it will never have more than 17V across it so I wasn't worried about exposed joints etc either, was more about keeping it cool if I wanted to load up right up.
Yeah Rose-Bopla makes some nice boxes; I love their epoxy painted cast junction boxes with brushed AL face. The look is SO enigmatic.
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
They also make some delicious SS boxes and IP67/69 cabinets. Delicious pricetags too.
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
mnem
*Industrial Supply Junkie*
Ok so help request. How the hell do I get a stuck scope case off. It appears that the outer shell is deformed on one side and won't slide more than about 4 inches back from the front. I'd usually just lump it with a hammer until it's off but that's a stupid idea when the thing has a CRT in it.
No, if it's like the 2230, it's hanging up on the serial port on the side. Look inside, you may have to pry out on the edge of the opening a LITTLE to get it past the flange. If it's really deformed, I think you can take the entire expansion card off from the outside.
[EDIT] Big "Gotcha" on these: If you aren't extra careful taking it apart, you can VERY easily damage the 0.100" cable for the encoder pot at the top-center of the panel. The case likes to hang up on it. BIG TIME.
[/EDIT]
mnem
Got it off. Total bastard that was. Side of case wouldn’t slide off. Carefully tapped a metal ruler down the side and worked it off slowly
Edit: it's had a knock to the side on the handle which has pushed it inwards. Also looks like focus resistors are fine. Fuuuu. Another money sink here I come!
Got it off. Total bastard that was. Side of case wouldn’t slide off. Carefully tapped a metal ruler down the side and worked it off slowly
Edit: it's had a knock to the side on the handle which has pushed it inwards. Also looks like focus resistors are fine. Fuuuu. Another money sink here I come!
And so it starts. Murphy got you again.
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Edit, the resistors can look just fine but still be open. Check them anyway.
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 ![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
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 ![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
Hmmm?
o--1Ω--o--2Ω--o = 3Ω R
1| |
o--3Ω--o--4Ω--o = 7Ω R
2| |
o o
+ Measure -
R
1 x R
2 21
--------- = ----- = 2.10Ω
R
1 + R
2 10
Should yield 2.10Ω
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif)
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.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
mnem
Still crazy math-defective after all these years...
Got it off. Total bastard that was. Side of case wouldn’t slide off. Carefully tapped a metal ruler down the side and worked it off slowly
Edit: it's had a knock to the side on the handle which has pushed it inwards. Also looks like focus resistors are fine. Fuuuu. Another money sink here I come!
And so it starts. Murphy got you again. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Edit, the resistors can look just fine but still be open. Check them anyway. ![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
*Says a prayer for bd's sanity over the next few days*
mnem
Coming from me... will that help or hinder...?
Got it off. Total bastard that was. Side of case wouldn’t slide off. Carefully tapped a metal ruler down the side and worked it off slowly
Edit: it's had a knock to the side on the handle which has pushed it inwards. Also looks like focus resistors are fine. Fuuuu. Another money sink here I come!
And so it starts. Murphy got you again. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Edit, the resistors can look just fine but still be open. Check them anyway. ![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
Have checked them all. R182 is reading 1M but it's got the focus pot across it of 2.2M so should read about 700k. Focus pot be open!
Ergo at least I know what the problem is!
Going to check the voltage across R182 when it's powered up and find a suitable replacement pot for it. Bourns do some cermet ones that are good to 500V or so. Hopefully it's less than that!
Got it off. Total bastard that was. Side of case wouldn’t slide off. Carefully tapped a metal ruler down the side and worked it off slowly
Edit: it's had a knock to the side on the handle which has pushed it inwards. Also looks like focus resistors are fine. Fuuuu. Another money sink here I come!
And so it starts. Murphy got you again. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Edit, the resistors can look just fine but still be open. Check them anyway. ![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
Have checked them all. R182 is reading 1M but it's got the focus pot across it of 2.2M so should read about 700k. Focus pot be open!
Ergo at least I know what the problem is!
Going to check the voltage across R182 when it's powered up and find a suitable replacement pot for it. Bourns do some cermet ones that are good to 500V or so. Hopefully it's less than that!
Good deal. You may be able to fix it. Is it open across the resistive element or the wiper? if wiper there's a chance it could be fixed.
Diagnostics complete. Pot is nuked from end to end.
![ThumbsDown :--](https://www.eevblog.com/forum/Smileys/default/icon_thumbsdown.gif)
Turns out 2.2M pots are virtually impossible to find in the UK ... usual places dont have anything suitable. May have to bodge something.
Diagnostics complete. Pot is nuked from end to end. ![ThumbsDown :--](https://www.eevblog.com/forum/Smileys/default/icon_thumbsdown.gif)
Turns out 2.2M pots are virtually impossible to find in the UK ... usual places dont have anything suitable. May have to bodge something.
If you can't find something let me know and I'll order it from here and send it to you.
Thanks everyone for offers and suggestions.
No luck finding anything yet. Piher do a close one but it will require some shaft adaptation and the hole is slightly too small. Original was a Citec unit.
So after much wiggling and swearing, a Citec 2.2M linear carbon 20%, 0.25W, 250V max rating. 8/10mm hole, 4mm shaft pot popped out.
There's a close-ish Piher one available on rapid but shaft is 6mm which will require some mechanical adaptation but should do the job. Will try TME and some other shops first and the junk box as I've got hundreds of the damn things in already.
![](http://i1183.photobucket.com/albums/x462/mnemennth/HP%20P-N%2019511-80014.jpg)
*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 ![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
*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).
Just found a 2.5M pot in the junk box that's reading 2.3M across it ... will try that
Well that was fun.
Bodged the pot in loose to start with just to check it worked.
![](https://i.imgur.com/LiR6kEZ.jpg)
Bingo!
![](https://i.imgur.com/RNQ5UDm.jpg)
nice and crisp as well. Need to modify the pot slightly to get it in the hole. Will do that this evening.
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.
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:
![](https://i.imgur.com/tKiGXWF.jpg)
![](https://i.imgur.com/YzKJkTA.jpg)
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!