Test Equipment Anonymous (TEA) group therapy thread

[med6753]

Seems lately I have to constantly justify my methods of repair/restoration to the point to where maybe I'll stop sharing. Or perhaps I'm just in a bad mood. Hasn't been a very Merry Christmas.

It's your scope and you can do whatever you choose, just don't call me "dumb" because I don't want to shotgun replace* every single old capacitor in my equipment, they do however get measured to check the value & ESR and ripple when powered up.
Capacitors that have obviously failed with perished/cracked seals or electrolyte leakage do get replaced, as do paper bumble bombs/black beauties & wax paper capacitors, I still give them a Megger leakage test after replacing to find out how bad they are.

*Towards the end of the lab at work it got very boring just shotgun replacing all electrolytic capacitors, but that was very necessary due to corrosive leakage, much preferred fault finding.

David

I'm not calling any individual "dumb" but I do find it interesting that my method of proactive capacitor replacement is under constant scrutiny. And in fact it's hypocrisy. How so? What is the first thing 99% of techs/engineers do when confronted with vintage audio equipment? That's right....100% of capacitor replacement without question (except mica's and ceramic's). So why should our vintage test equipment be treated any differently? Don't we value it as much as the audio stuff? Well this boy does.     

[med6753]

I tend to agree up to the point where the alterations are plainly visible from the outside.

Have you ever seen any of my vintage equipment visibly altered?

I rest my case. 

Well.....OK....the 2465 fan bodge....but it isn't visible unless booty is your thing. 

[mnementh]

*Bites tongue out of consideration for years of friendship*

mnem
*Longtime practitioner of Ugly Engineering*

[SilverSolder]

Seems lately I have to constantly justify my methods of repair/restoration to the point to where maybe I'll stop sharing. Or perhaps I'm just in a bad mood. Hasn't been a very Merry Christmas.

It's your scope and you can do whatever you choose, just don't call me "dumb" because I don't want to shotgun replace* every single old capacitor in my equipment, they do however get measured to check the value & ESR and ripple when powered up.
Capacitors that have obviously failed with perished/cracked seals or electrolyte leakage do get replaced, as do paper bumble bombs/black beauties & wax paper capacitors, I still give them a Megger leakage test after replacing to find out how bad they are.

*Towards the end of the lab at work it got very boring just shotgun replacing all electrolytic capacitors, but that was very necessary due to corrosive leakage, much preferred fault finding.

David

I'm not calling any individual "dumb" but I do find it interesting that my method of proactive capacitor replacement is under constant scrutiny. And in fact it's hypocrisy. How so? What is the first thing 99% of techs/engineers do when confronted with vintage audio equipment? That's right....100% of capacitor replacement without question (except mica's and ceramic's). So why should our vintage test equipment be treated any differently? Don't we value it as much as the audio stuff? Well this boy does. 

Both approaches have merit.   As in all cases where there is more than one good solution to a problem, people will be arguing which is best - but it is really marginal!

I have had to change electrolytic capacitors in older test gear - but the high quality replacements (similar specs to the original) are not cheap, so I don't do it unless they are actually broken.  So, my take on it is -  I'd rather save the money and buy even more old test gear! 

[mnementh]

I'm not calling any individual "dumb" but I do find it interesting that my method of proactive capacitor replacement is under constant scrutiny. And in fact it's hypocrisy. How so? What is the first thing 99% of techs/engineers do when confronted with vintage audio equipment? That's right....100% of capacitor replacement without question (except mica's and ceramic's). So why should our vintage test equipment be treated any differently? Don't we value it as much as the audio stuff? Well this boy does.     

Well, that pool of enthusiasts has a much higher voodoo promulgating fuckwit : Actual Tech ratio than our little enclave of TE enthusiasts, so one could easily argue that their application of the scattergun approach is more "change parts and hope you hit the broad side of a barn" technique rather than "diagnose like you know what you're doing and fix what's actually broken".

That said... I've seen too many cases of scattergun approach fixing things you didn't even know were wrong (noisy trace, poor clarity, marginal brightness on screens and displays) to discount it so foolishly. I see it more as a first diagnostic step once gear reaches drinking age. If it's old enough to qualify for a AARP card, it has been running on borrowed time for decades; and again, just because "it works" doesn't mean it's really working correctly.

Electrons are finicky things... they're lazy, but they do love to make trouble.   Freshening up the capacitors puts young constables with feet on the ground back into that mix.

mnem
9. Capacitors are Murphy's footsoldiers.

[Saskia]

@med I can't think of anything wrong with your approach.
Period.

[Ice-Tea]

Accidently, on a slightly more TEA related note: I've been looking for a working 15GHz+ RF generator. Doesn't have to be super accurate, but does have to work. I'm not looking for another project (God, no..).

So if one of you eBay addicts comes accross something: let me know!

A HP 8620C* series sweeper with a 86290B or C module would go to 18.6GHz, CW mode if you want a fixed frequency, but finding a working one with all the correct frequency scales will be expensive. I have one working frame and two lower frequency modules, still looking for a cheap 86290A module as I have the scales for that one and need something to higher frequency check some of the counters here.

*There are more in the US and some aren't to expensive, but shipping is way too much, lots of sellers asking way to much for untested modules without the scales too.
https://www.ebay.com/itm/184534651374

David

Interesting. Thanks for the suggestion. Wouldn't mind paying the price or even the shipping fee if I knew it was fully functional and reasonably stable. HAd been looking at 8672's, 8620's are going on my watchlist..

[AVGresponding]

[bd139]

I'm not calling any individual "dumb" but I do find it interesting that my method of proactive capacitor replacement is under constant scrutiny. And in fact it's hypocrisy. How so? What is the first thing 99% of techs/engineers do when confronted with vintage audio equipment? That's right....100% of capacitor replacement without question (except mica's and ceramic's). So why should our vintage test equipment be treated any differently? Don't we value it as much as the audio stuff? Well this boy does.     

Well, that pool of enthusiasts has a much higher voodoo promulgating fuckwit : Actual Tech ratio than our little enclave of TE enthusiasts, so one could easily argue that their application of the scattergun approach is more "change parts and hope you hit the broad side of a barn" technique rather than "diagnose like you know what you're doing and fix what's actually broken".

That said... I've seen too many cases of scattergun approach fixing things you didn't even know were wrong (noisy trace, poor clarity, marginal brightness on screens and displays) to discount it so foolishly. I see it more as a first diagnostic step once gear reaches drinking age. If it's old enough to qualify for a AARP card, it has been running on borrowed time for decades; and again, just because "it works" doesn't mean it's really working correctly.

Electrons are finicky things... they're lazy, but they do love to make trouble.   Freshening up the capacitors puts young constables with feet on the ground back into that mix.

mnem
9. Capacitors are Murphy's footsoldiers.

On the capacitors, I'm sort of on the fence with this once. I work on the following replacement principle, objectively only:

1. Likely to blow up in your face or burn your house down (RIFAs, Schaffner filters)
2. Likely to cause secondary damage when it fails (some electrolytics, tantalums)
3. Likely to cause functional issues (some electrolytics, some paper/wax capacitors, some HV capacitors)
4. Likely to be difficult to replace later while you've got the thing in pieces anyway (anything on inspection)

Shotgunning them is expensive and in some cases extremely difficult to do without causing further damage to the item in question. Secondarily you risk causing more problems through unexpected side effects, different component properties (consider the much lower ESR of most modern electrolytics etc). Ergo make rational, objective steps only. About 50% of the time that does result in shotgunning but should not be confused with a blanket shottgunning policy.

[bd139]

I live down the road from there. Still haven't been to it! Not holding up any hopes for a visit in 2021 

[bd139]

I've caught a lot of flak on Tek Facebook group concerning my removal of cans to accommodate the replacement capacitors. It destroys, according to these critics, the "vintage aesthetics" of the instrument. Well...boo hoo. I will retain the cans if possible but that is not a priority. My priority is an instrument which functions to spec and is reliable. You can't guarantee any long term reliability with those aluminum time bombs. These are the same guys who will run to fail and then only replace what has failed. That's dumb. Better to be proactive and replace them all in one shot and be done with it.     

I only have to reply to this one with "fuck 'em". Bunch of miserable bastards  .

There are two classes of restoration: functional and museum. I am definitely a fan of functional because what is the point in something existing if it's not going to have any function capability. That's one of the things I love about TE - it's functional, not some inert object which does nothing other than looks a certain way. The Science Museum here is full of things which could be part of a functional exhibit but in fact it's like watching taxidermy rather than nature. TNMOC gets it about right - most of their stuff is functional or at least they're trying to get it there!

As for what to replace, see my post above. I think there's a compromise somewhere between shottgunning and whack-a-mole. I think that's what you do TBH. I've seen both extremes and they're not very productive.

[mnementh]

I tend to agree to an extent: Big expensive ones like the blue beercans in a 24xx are worth the time to take out of circuit and measure for value/tan δ/leakage current.

Ones where you can easily damage things getting to them or removing them get similar special consideration; test to the best of ability in circuit. Smaller, cheaper brute force filtering and decoupling caps on power rails you can do in one fell swoop... and cherry bomb tants, RIFAs, waxpaper, etc types known to fail... I say "Kill 'em all, let your god sort 'em out." 

That is what I mean by "scattergun approach" anyways... I rarely include coupling and small-signal caps in that attack.

 I get where factory is coming from too; those big cans are a pretty big PITA to change out, so I can see spending a little time on them... tho my personal opinion is that any 60-year-old electrolytic in a brute-force filtering role is at best a zombie looking for a place to fall down and die. Aluminium loves to exchange ions with its neighbors; after 6 decades, the odds of it not having done a lot of that are damned slim. Just because you can't measure it yet doesn't mean they aren't compromised.

mnem
 

[mnementh]

Kempton Steam Museum - Mercury Arc Rectifiers: https://youtu.be/YhaQqgXrMMU

That is some fucking delicious old-school "Dr. Frankenstein's Laboor-a-toory angry-pixies-in-a-bottle" type shit right there. Thanks for sharing!

mnem
 

[0culus]

Accidently, on a slightly more TEA related note: I've been looking for a working 15GHz+ RF generator. Doesn't have to be super accurate, but does have to work. I'm not looking for another project (God, no..).

So if one of you eBay addicts comes accross something: let me know!

If you don't need a sweeper, look for an 8672A. It has the advantage of having essentially the same synthesis architecture as the 8566B SA, so there's lots of info on working on it (and even modifying it). There's also a frequency extension box for it you might be lucky enough to find that extends the low frequency to 0.1 MHz instead of 2 GHz.

[Neomys Sapiens]

Accidently, on a slightly more TEA related note: I've been looking for a working 15GHz+ RF generator. Doesn't have to be super accurate, but does have to work. I'm not looking for another project (God, no..).

So if one of you eBay addicts comes accross something: let me know!

Maybe this one is for you.

https://www.ebay.de/itm/Agilent-hp-8350A-Synthesized-Sweep-Signal-Generator-10MHz-Sich-20-GHZ/124496531649
 

[AVGresponding]

FINALLY bagged myself a half decent awg, TTi TG2511A, price: don't ask.   

Also missed a NI GPIB-USB because stupid   

[bd139]

FINALLY bagged myself a half decent awg, TTi TG2511A, price: don't ask.   

Also missed a NI GPIB-USB because stupid   

I’d have bought a DG811 and cracked it for that price 

Let us know how it goes. Not sure anyone has had one on here.

[Specmaster]

https://www.cp24.com/world/downtown-nashville-explosion-knocks-communications-offline-1.5245060

A recreational vehicle parked in the deserted streets of downtown Nashville exploded early Christmas morning, causing widespread communications outages that took down police emergency systems and grounded holiday travel at the city's airport...

Jeebus. Bet you a dollar it was another home-grown terrorist Anti-5G wingnut. 

mnem
*crawls back into his cave*

Yep, thats what I  thought also as soon as I discovered it was outside AT&T. Perhaps the worlds authorities might now wake and do something about these nutters before more loss of life ensues as a result.

[bd139]

Perhaps he was just a normal AT&T customer who had enough 

[McBryce]

holy crap ....... what a unique bunch of wingnuts hang out on this thread!

christmas day and you decide to argue over which feckin' potato peeler design is best!

merry christmas you wacky bastards!

The best Vegetable Peeler I have had was a 25 year old Bouncy Blonde Chick who worked for me 

Pictures or I call wishful thinking. 

On the left  Her Sister also worked for me for 6 or 7 years but was slightly less aPeeling due to being married 

Blonde....check
Bouncy....check
You delivered.....check

 

Lacking a mate who peels veggies for me (I don't know why he expects me to do that kind of work, honestly, no idea), I am looking for a suitable lathe.

Any self respecting machinist will tell you, peeling veggies requires a milling machine too, not just a lathe:



McBryce.

[Saskia]

I stand corrected and will try better next time.

Currently looking for an Okuma B series ...

[Ice-Tea]

Maybe this one is for you.
https://www.ebay.de/itm/Agilent-hp-8350A-Synthesized-Sweep-Signal-Generator-10MHz-Sich-20-GHZ/124496531649
 

Mhh.. Not bad. Any affiliation with the seller? I think I'll ask him if/how he knows the unit is OK (if he does) the plan is to eliminate some variables, not to add them.

If you don't need a sweeper, look for an 8672A. It has the advantage of having essentially the same synthesis architecture as the 8566B SA, so there's lots of info on working on it (and even modifying it). There's also a frequency extension box for it you might be lucky enough to find that extends the low frequency to 0.1 MHz instead of 2 GHz.

Great Brilliant minds think alike:

Interesting. Thanks for the suggestion. Wouldn't mind paying the price or even the shipping fee if I knew it was fully functional and reasonably stable. HAd been looking at 8672's, 8620's are going on my watchlist..

[Specmaster]

I live down the road from there. Still haven't been to it! Not holding up any hopes for a visit in 2021 

Likewise, I both walked and driven past the doors to that building literally 1000's of times in the last 20 years as the HQ and factory of my old company I was working for at the time was just a mile further on along the A315 there at Commerce Road, close to the Holiday Inn (Brentford Lock), small world, isn't it? I always said to myself that One day I'd visit the museum but never did  On another occasion we had our Christmas lunch at the London Apprentice (where they loaded Concord onto the Barge for her sea trip to Edinburgh) and another year we had a Christmas party at the function rooms of Twickenham Rugby Stadium so have been circling your gaff for years 

[Specmaster]

Gah, just lost an attempt to snaffle a nice TTi TG2511A function generator on eBay today, had my finger hovering over the mouse ready to submit my bid for £150 but suddenly leapt at the dieing seconds from £140 to £195, so was that anyone from this thread? If so you grabbed what looked like a great bargain there but was way over my budget 

[Specmaster]

FINALLY bagged myself a half decent awg, TTi TG2511A, price: don't ask.   

Also missed a NI GPIB-USB because stupid   

So it was you who won it at the end then, well done, it is still current piece of kit as well, I hope it also comes with all the leads etc, keep us all posted on it when it arrives and how it goes etc.