Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

Also did some TEA. Not much though. Went to a Radio rally at Kings Lynn, about an hours drive. Due to wet weather yesterday and poor forecast today it was poorly attended, particuarly by selllers. One thing caught my eye. An Advance OS250 'scope but with a blue filter on the CRT.  So I bought it at huge expense £10  And it basically works and does have a blue trace. But it looks like a normal green CRT with a theatre lighting type "gel" blue filter in front of it. So not an odd phosphor CRT.

I suppose I could do a 'scope clock.

[Vince]

A clock ? I vividly remember a few months ago you already rescued a crusty old scope, saying you would make a clock with... so that will be TWO scope clocks ?!
I guess your lab is very large and you need  a clock in each corner of it 

[Robert763]

Oh workshop is not big, but already has a pair of GPSDO's with time displays. One at each end :-)
Yes I did buy another 'scope for a clock. I've only got one clock PCB though.
 

[EggertEnjoyer123]

I got my 16W08 ICs today (for replacing the NVRAM on my Tek scope).

Can I solder the chip to the adapter first before programming it, or does it have to be programmed before soldering? I don't have the adapter for that package, so I would prefer soldering first.

[Vince]

Tek 2465 PSU recap

Getting there.
Have been on Farnell's website for 2 hours now. All the alu caps are in the cart.

Now I am starting the search for the X/Y caps and... boy this PSU drives me nuts, I am still wasting time trying to understand what to buy. Nothing is simple.... unless you just buy "some" cap and cross fingers.
Unfortunately, for the better or worse, I am not that kind, I like to understand what I am doing if I can...

So I am trying to understand once and for all this X/Y cap thing.

My problem right now is that the RIFA's I am trying to replace, 5 of them, are marked 'Y' or 'X'... but it does not say if it Y1/2/3...... nor if it's X1/2/3/4/5....

So I Googled and found this interesting page. I find it concise but quite clear and with interesting technical details.
So if like me you still need to gt the basics straight on these bloody caps, you might want to have a quick look :

https://www.doeeet.com/content/eee-components/passives/x-and-y-safety-capacitor-applications-explained/

So :

- Y caps are more demanding, they are designed to be safer that X caps.
However they don't say in what way they are safe, nor if that means that a Y cap can be safely be used to replace an X cap for example. So to avoid troubles I will just avoid doing that...

- Both for X or Y caps, the number after the letter indicates the performance / spec of the cap.

- For both X and Y caps, the higher the number/digit, the shitter it is.


So in my case I guess since I don't know what spec these caps are, I can just buy X1 and Y1 and  it should be safe.

ALSO : I am glad I do read the datasheet of every cap I buy... most of these caps come with ultra short leads, like 3mm, just long enough to traverse the PCB. So you need to make 100% sure the pitch of the new cap matches the old cap, otherwise big trouble.
Also, I of course will buy some extra caps, and having short leads reduces their usefulness : you don't know what you might have to do to fit these caps to accommodate whatever board / TE you might want to fit them to ! Having long leads gives you the flexibility to adapt to a different pitch, bigger or smaller, or also mount them flat on the board if so required, or make them lean a bit in order to clear surrounding components or metal work or whatnot.

So... I really wanted long leads, so paid attention to that in the data sheet. turns out KEMET sells their caps with 3 different lead length choices. 3, 4 and 25mm. The 25mm which I will buy of course, are like 40% more expensive !!!     So the few milligrams of copper in the leads is worth as much as the cap itself ?! 


Sorry for the disturbance, I will go back to ordering my X/Y caps now...


EDIT :  I see that Farnell has about, literally, an order of magnitude more X2 caps for sale than X1, and same for Y2 caps versus Y1. So I guess that's a good indication that it's fairly safe to default to X2 and Y2 caps when recapping our TE, when the digit is not specified on the caps like is the case here.

EDIT #2 : Good lord, I see that the RIFA's nwo exist in..... SURFACE MOUNT packages ?:   

They cost 5 times more than the TH versions though.

https://fr.farnell.com/kemet/smp253ma4220mtr24/cond-suppression-2200pf-y2-250v/dp/3350790

EDIT #3 : I guess I should not have made fun of Yaego caps earlier... looking at KEMET's datasheet, I see that Yaego BOUGHT Kemet ?! 
Was Yageo a sleeper all along, or is it a case of FIAT buying Ferrari, or Ford buying Jaguar ?! 

EDIT #4 : bummer, I need a 2.2nF Y cap and I can't find any with long leads, grrrr... not gonna buy 10 of them then... only the 2 I need for this recap and that's it.

EDIT #5 : I spoke too soon, will have to buy 10 of them anyway, it's the minimum order! 

EDIT #6 : OK I leave you alone now, I will go and hide...

[TERRA Operative]

I got my 16W08 ICs today (for replacing the NVRAM on my Tek scope).

Can I solder the chip to the adapter first before programming it, or does it have to be programmed before soldering? I don't have the adapter for that package, so I would prefer soldering first.

It doesn't make a difference. I programmed mine after the chips were mounted on the adapters as it was easier to stick the chip-on-adapter into the programmer.

Tek 2465 PSU recap

Getting there.
Have been on Farnell's website for 2 hours now. All the alu caps are in the cart.

Now I am starting the search for the X/Y caps and... boy this PSU drives me nuts, I am still wasting time trying to understand what to buy. Nothing is simple.... unless you just buy "some" cap and cross fingers.
Unfortunately, for the better or worse, I am not that kind, I like to understand what I am doing if I can...

X class caps go across line (can fail short, and will blow the line fuse)
Y class caps go from line to earth (designed so they CANNOT fail short)

Y can replace X, but X CANNOT replace Y (You don't want an X class cap shorting out and applying voltage to the chassis!)

The lower the number after the X/Y, the higher the rated voltage and peak impulse rating.

Just buy X/Y, X1/Y1, or X2/Y2 rated caps, then they can be used anywhere as they are dual-rated. Use the highest voltage rating that will fit the original physical dimensions and pitch. (A few fractions of a mm larger in physical size is usually not a problem). I have found lead length is not much of a problem for PCB's, I've only actually needed the longer leads when the caps are wired point-to-point on the terminals on the back of the IEC sockets.

For our purposes, X2/Y2 is fine, just get the highest rated voltage you can and you don't have to worry any further.


Here's another link that might help clarify things:
https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

[Robert763]

It is a common fallacy that Y rated suppression capacitors "cannot" fail short circuit. Of course they can, particuarly if you exceed their ratings. And therin lies the truth.
Whilst a X and a Y capacitor (of similar value and construction) may be rated at the same 250V AC the Y is larger. Why? because it has thicker dielectric with a higher "real" voltage rating. The surge and spike voltage specifications are higher for a Y capacitor (Y1 has a 8kV test voltage X1 is 4kV). They also, depending on the subclass have more stringent test requirements.

So Y capacitors are MORE RELIABLE and LESS LIKELY TO BE EXPOSED TO VOLTAGES ABOVE THEIR PEAK RATING than a X capacitor.
BTW small Y ceramics are a cheap source of high voltage ceramics for low energy HV like GM tubes and PMT.

Robert.

[TERRA Operative]

I should edit to say shouldn't fail short, and are designed to fail open to minimise the chance of short, but meh.... semantics.

[TERRA Operative]

Aaannnnd I just bought a THS720A...
Seller says it works, but no photos of it turned on.
Comes with a bag, probes, dead battery (simple to rebuild) and a few accessories.
I'll update firmware, repack the battery, maybe add LED backlight to the LCD, and hack it up to a THS720P and sell it off with a new foam insert in the bag hopefully at a profit.

[tggzzz]

Aaannnnd I just bought a THS720A...

From Waterlooville, I believe

[med6753]

Tek 2465 PSU recap

Getting there.
Have been on Farnell's website for 2 hours now. All the alu caps are in the cart.

Now I am starting the search for the X/Y caps and... boy this PSU drives me nuts, I am still wasting time trying to understand what to buy. Nothing is simple.... unless you just buy "some" cap and cross fingers.
Unfortunately, for the better or worse, I am not that kind, I like to understand what I am doing if I can...

So I am trying to understand once and for all this X/Y cap thing.

My problem right now is that the RIFA's I am trying to replace, 5 of them, are marked 'Y' or 'X'... but it does not say if it Y1/2/3...... nor if it's X1/2/3/4/5....

So I Googled and found this interesting page. I find it concise but quite clear and with interesting technical details.
So if like me you still need to gt the basics straight on these bloody caps, you might want to have a quick look :

https://www.doeeet.com/content/eee-components/passives/x-and-y-safety-capacitor-applications-explained/

So :

- Y caps are more demanding, they are designed to be safer that X caps.
However they don't say in what way they are safe, nor if that means that a Y cap can be safely be used to replace an X cap for example. So to avoid troubles I will just avoid doing that...

- Both for X or Y caps, the number after the letter indicates the performance / spec of the cap.

- For both X and Y caps, the higher the number/digit, the shitter it is.


So in my case I guess since I don't know what spec these caps are, I can just buy X1 and Y1 and  it should be safe.

ALSO : I am glad I do read the datasheet of every cap I buy... most of these caps come with ultra short leads, like 3mm, just long enough to traverse the PCB. So you need to make 100% sure the pitch of the new cap matches the old cap, otherwise big trouble.
Also, I of course will buy some extra caps, and having short leads reduces their usefulness : you don't know what you might have to do to fit these caps to accommodate whatever board / TE you might want to fit them to ! Having long leads gives you the flexibility to adapt to a different pitch, bigger or smaller, or also mount them flat on the board if so required, or make them lean a bit in order to clear surrounding components or metal work or whatnot.

So... I really wanted long leads, so paid attention to that in the data sheet. turns out KEMET sells their caps with 3 different lead length choices. 3, 4 and 25mm. The 25mm which I will buy of course, are like 40% more expensive !!!     So the few milligrams of copper in the leads is worth as much as the cap itself ?! 


Sorry for the disturbance, I will go back to ordering my X/Y caps now...


EDIT :  I see that Farnell has about, literally, an order of magnitude more X2 caps for sale than X1, and same for Y2 caps versus Y1. So I guess that's a good indication that it's fairly safe to default to X2 and Y2 caps when recapping our TE, when the digit is not specified on the caps like is the case here.

EDIT #2 : Good lord, I see that the RIFA's nwo exist in..... SURFACE MOUNT packages ?:   

They cost 5 times more than the TH versions though.

https://fr.farnell.com/kemet/smp253ma4220mtr24/cond-suppression-2200pf-y2-250v/dp/3350790

EDIT #3 : I guess I should not have made fun of Yaego caps earlier... looking at KEMET's datasheet, I see that Yaego BOUGHT Kemet ?! 
Was Yageo a sleeper all along, or is it a case of FIAT buying Ferrari, or Ford buying Jaguar ?! 

EDIT #4 : bummer, I need a 2.2nF Y cap and I can't find any with long leads, grrrr... not gonna buy 10 of them then... only the 2 I need for this recap and that's it.

EDIT #5 : I spoke too soon, will have to buy 10 of them anyway, it's the minimum order! 

EDIT #6 : OK I leave you alone now, I will go and hide...

Vince, follow this guide and I guarantee success with your 2465 PSU re-cap.

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102

Take special note: Do ONE capacitor at a time and verify value/voltage/polarity. There is a documented mistake in the manual which will lead you down a heartbreak path if you don't observe this advice.

[TERRA Operative]

Aaannnnd I just bought a THS720A...

From Waterlooville, I believe

Nah, Yahoo Auctions, again... 



Also, I got a TDS540 working tonight! It had the usual leaky capacitors, which were all swapped out with new after removing the old and running the boards through the dishwasher. Luckily there was very little actual leakage, except for the two caps on the Voltage Controlled Oscillator daughterboard on the Acquisition PCB which puked their guts out good and proper... 
That board wasn't worth repairing, so I whipped a new one up in Diptrace and ordered some parts from Mouserkey.
Unfortunately, there is one part that is obsolete (wouldn't be a decent repair if at least one part wasn't unobtanium!) but luckily it was on the opposite end of the PCB to the leaky caps so it was perfectly reuseable.
The part in question is a MMBV105G, a 'silicon tuning diode' or 'voltage variable capacitance diode' or some such thing. If anyone has a suggestion for a drop-in substitute, let me know!

Anyway, with that done, Rifa caps replaced, options unlocked (I threw a spare serial/centronics option card in) and everything buttoned up, it works as perfectly as the day it was born. Nice! 



I swear, I'm gonna make a TDS-henge in the garden for a laugh and a photo with all these scopes one day. I almost have enough of the damn things! 

[factory]

Tek 2465 PSU recap

Getting there.
Have been on Farnell's website for 2 hours now. All the alu caps are in the cart.

....snip....

Sorry for the disturbance, I will go back to ordering my X/Y caps now...


EDIT :  I see that Farnell has about, literally, an order of magnitude more X2 caps for sale than X1, and same for Y2 caps versus Y1. So I guess that's a good indication that it's fairly safe to default to X2 and Y2 caps when recapping our TE, when the digit is not specified on the caps like is the case here.

EDIT #2 : Good lord, I see that the RIFA's nwo exist in..... SURFACE MOUNT packages ?:   

They cost 5 times more than the TH versions though.

https://fr.farnell.com/kemet/smp253ma4220mtr24/cond-suppression-2200pf-y2-250v/dp/3350790

EDIT #3 : I guess I should not have made fun of Yaego caps earlier... looking at KEMET's datasheet, I see that Yaego BOUGHT Kemet ?! 
Was Yageo a sleeper all along, or is it a case of FIAT buying Ferrari, or Ford buying Jaguar ?! 

EDIT #4 : bummer, I need a 2.2nF Y cap and I can't find any with long leads, grrrr... not gonna buy 10 of them then... only the 2 I need for this recap and that's it.

EDIT #5 : I spoke too soon, will have to buy 10 of them anyway, it's the minimum order! 

EDIT #6 : OK I leave you alone now, I will go and hide...

Thanks for that link to the surface mount RIFA Papier Métallisé madness, had a good laugh at those. 

Yageo are from Taiwan, quick web search suggest Teapo & Jamicon are part of the same company, definitely FIAT/Ford of caps IMO.

If it helps, these are the caps I used to replace the RIFA paper crap in my Tek 24xx scopes;

2x 2.2nF Y2 Epcos B32021A3222K000
1x 10nF Y2 Epcos B32032A4103M000
1x 68nF X2 Vishay F1772SX236831KFIB0
1x 56nF X2 Wurth 890324023017CS

Anything that wasn't a paper RIFA was left in place.

No idea if I have any left over, lead length probably wasn't very long, should be in the box with the rest of the bits if I do. This is an unfinished project, still got one out of the four scopes to finish, hence the old caps were still here.

David

[Vince]

Tek 2465 PSU recap
Getting there.

Vince, follow this guide and I guarantee success with your 2465 PSU re-cap.

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102

Take special note: Do ONE capacitor at a time and verify value/voltage/polarity. There is a documented mistake in the manual which will lead you down a heartbreak path if you don't observe this advice.

Hello Papa Smurf,

Yes, one cap at a time indeed.
I already recapped my 2467B some time ago, so this is my second time now. First time I was scared and struggled, but I guess it was good experience because now, having to do it a second time, feels so much easier and quicker. No stress.

I don't know what this error in the manual is exactly, though I keep hearing there is some kind of error.
That being said, I never use manuals to recap a TE. I take it for granted that manuals (can) have errors, and/or there might revisions, slight variations depending on serial number or change in suppliers, that may not be covered by the manual one has.

So I just completely ignore the manual and simply look at what's on the board and put the same thing back in, simple.
The only time I may consult the manual, and well, have done here in this case, is to identify a burned component, resistor here, because it has become unidentifiable.
Or, for example if a component looks suspicious, like it's not original and I have therefore a doubt about the specs of that component.

My problem with this scope really isn't the recap but... the freaking brushless fan motor that's kaput and is not sold new anymore.
Without cooling, I can't use this scope of course. Hybrids and all that...

That.... is a big problem..... a show stopper no less.
I can just replace it with a brushed motor because I guess it would make lots of sparks that would disturb this delicate instrument...
Maybe I can find modern brushless motor that might fit, even if that means I have to design and build a new control PCB for it.

[Vince]

Also, I got a TDS540 working tonight! It had the usual leaky capacitors, which were all swapped out with new after removing the old and running the boards through the dishwasher. Luckily there was very little actual leakage, except for the two caps on the Voltage Controlled Oscillator daughterboard on the Acquisition PCB which puked their guts out good and proper... 
That board wasn't worth repairing, so I whipped a new one up in Diptrace and ordered some parts from Mouserkey.

Unfortunately, there is one part that is obsolete (wouldn't be a decent repair if at least one part wasn't unobtanium!) but luckily it was on the opposite end of the PCB to the leaky caps so it was perfectly reuseable.
The part in question is a MMBV105G, a 'silicon tuning diode' or 'voltage variable capacitance diode' or some such thing. If anyone has a suggestion for a drop-in substitute, let me know!

I swear, I'm gonna make a TDS-henge in the garden for a laugh and a photo with all these scopes one day. I almost have enough of the damn things! 

Wow.... you buy them faster than you can fix and sell them. I am sure they are all over the house, hiding in the cup board, under the dining table, atop the fridge, and that the missus will soon start to complain. I guess you should start building an extension to your lab to store all those TE...

The diode we call " Varicap" over here... well I thought that was the English name for it actually, looks like maybe not then. Used in radios and TVs for tuning, as I understand it. Glad you didn't have to replace it then in the end.

[Vince]

Tek 2465 PSU recap

Yageo are from Taiwan, quick web search suggest Teapo & Jamicon are part of the same company, definitely FIAT/Ford of caps IMO.

Jamicon as well ?! Oh dear, it's not even Ford territory then, we just switched to lada and tata ! 

If it helps, these are the caps I used to replace the RIFA paper crap in my Tek 24xx scopes;

Too late, I placed my order last night, UPS just sent me an e-mail saying they should deliver them to me tomorrow afternoon, can't wait...

[m k]

My problem with this scope really isn't the recap but... the freaking brushless fan motor that's kaput and is not sold new anymore.
Without cooling, I can't use this scope of course. Hybrids and all that...
...
Maybe I can find modern brushless motor that might fit, even if that means I have to design and build a new control PCB for it.

Maybe somewhere is already an adapter board for HP model.

Can't you use any mechanics from HP one?

[Vince]

Oh no, just realised I passed the 4,000 posts mark... I will now spend the next 12 months going through the entire CMOS chip family !

[Vince]

My problem with this scope really isn't the recap but... the freaking brushless fan motor that's kaput and is not sold new anymore.
Without cooling, I can't use this scope of course. Hybrids and all that...
...
Maybe I can find modern brushless motor that might fit, even if that means I have to design and build a new control PCB for it.

Maybe somewhere is already an adapter board for HP model.

Can't you use any mechanics from HP one?

The HP motor won't help me as they don't grow on trees, nor are they affordable.
IT would be a viable idea if I had lots HP waiting to be scrapped for parts, but I don't.
If I want an HP motor I will have to buy it and again, they are both rare and expensive so.....

[Vince]

TEK fan motor : I just solved the problem... thanks to MK who convinced me to look closer at that Ebay add for an overpriced old HP fan.

I realised th seller Qservice, well known HP / Tek parts specialist, like Sphere used to be. Except Qservice has operations in the Euro zone, in Greece, so affordable shipping and no customs BS to deal with and pay for.

I saw they have a motor for me. Well they had two but only one left... I just bought meself one.

55+ euros shipped.

https://www.ebay.com/itm/234873314014?hash=item36af8a5ade

Quite expensive but cheaper than the HP ones, and tehy say they actually tested it, and foolish me I choose to believe them.

Hopefully this will let me button up this scope soon then I can move on to another TE.

It's expensive but it fixes my problem in the 'easiest and most OEM way, and I don't have a ton of other options do I.

I paid only 25 EUros for the scope, so add 55 for the motor + may 15 Euros worth of caps for the PSU... that 95/100 euros for a sorted 2465.
Still a hell of a deal around here.

I would still have to figure out the broken fan collet and its missing screw which I am sure is a freaking imperial thread 

[TERRA Operative]

Thos might be of interest:
https://groups.io/g/TekScopes/topic/2465_fan_collet/100511845

I have also been half thinking of getting some collets machined in China, It's on the loooong to-do list.

[wkb]

Now that  is a plan...  I cobbled something together for my 2465 but it is, cough, slightly excentric etc 

So curious here..

[Vince]

Oh thanks Terra ! 

I just posted a message over there, been years since I posted there !

[Vince]

OK the caps got delivered a couple hours ago. I just finished fitting them.

Recap is now 99.9% done.  Am just missing one single cap, that 3.3uF 350V one.

Then of course fix that fan motor and fan itself.

My soldering iron is really under powered. There are a few caps that sit flush on the PCB so you can't inspect the joint on the component side to make sure the solder flowed properly to the other side of the board.
Since my iron is under powered and some grounds had too high a thermal mass for my iron to handle comfortably... it makes me nervous. Some invisible joints are maybe not 100% good and might cause problems who knows.

So, I really, really really do need to buy a more powerful iron... there is just no way around it.

[DC1MC]

For Germans that want a good scope at an acceptable price (IMHO, not affiliated in any way with the seller):

https://www.kleinanzeigen.de/s-anzeige/tektronix-tds5054b/2515212504-168-4440



(If you can't do pick-up, use the EBAY-like buyer protection method provided by the site, it saved me a couple of times for a reasonable fee).

Cheers,
DC1MC