Test Equipment Anonymous (TEA) group therapy thread

[vk6zgo]

Never heard of Edward Hopper. But then my total knowledge of the art world wouldn't even fit on a thimble. 

Philistine! He was one of the best known American painters of the 20th Century, and from your home state no less. Next you're going to be telling us you've never heard of Norman Rockwell, also from New York.

That makes me a philistine as well because I've never heard of either of them 

The various avenues this thread takes from time can be very enlightening and entertaining, we have a very broad spectrum of intellects on here and that to my mind adds to the huge appeal of this lovely community we have built here, keep it chaps.

Yep, and I guess I can add "philistine" to my list of supposedly undesirable characteristics. If I were on the Titanic I'd barely qualify for 4th class and definitely be sleeping with the fishes. But that's OK. I'd rather be a "Low brow" rather than a "High Brow" with my nose in the air like my shit don't stink. My shit stinks, bad. 

Gee....now I'm gonna have to fight off Saskia with a stick. 

Cow Dung. I have Hubby.

Good, because have you ever met an angry black woman? Not pretty and life threatening. 

I value my life. 

Probably still pretty in your eyes, though!

[vk6zgo]

@med:

fixing those 2 tweeters is 130 € each.

The 2 crossovers, if I send them in: 250€. I guess I'll just source the parts ...

The woofer: have to ask how much my friend wants for reconing and recentering.
but tbh I think the crossover is dead as the tweeter fuse was blown in this speaker and the capacitors are well beyond EOL (about 15 years).

Back in the day, many 15 year old capacitors were just beginning their life!
A lot of stuff lasted 25-30 years before caps started to cause concern.

[vk6zgo]

Helmut Singer was a piss taker to the extreme!

Was that Anchor Supplies in Nottingham? I used to live walking distance from them yet had no idea they existed until after I moved away

Edit: footnote. Never live in Nottingham City area. Total fucking shit hole of a place.

Lot of problems with  Robin Hood & his gang? 

Bummer! med6753 beat me to the punch!
With a much funnier comment, too!

[Robert763]

Where in Mill Road, Cambridge was this H Gee's then, the only shops I can recall of interest in Mill Road was Cambridge Resale and Cash Converters, both were shops where poor students would take anything of value and sell / hock to meet their drinks / coke / rent debts and I managed to pick a few things of interest there years ago myself while I was living in Haverhill.

Just past the railway bridge going into town between the White Swan and St Barnabas church.

[Fungus]

While the capacitors still look ok, I cannot tell if they indeed are.

From the 1980s? It's safe to assume they aren't.

[Specmaster]

Where in Mill Road, Cambridge was this H Gee's then, the only shops I can recall of interest in Mill Road was Cambridge Resale and Cash Converters, both were shops where poor students would take anything of value and sell / hock to meet their drinks / coke / rent debts and I managed to pick a few things of interest there years ago myself while I was living in Haverhill.

Just past the railway bridge going into town between the White Swan and St Barnabas church.
(Attachment Link)

Gee, thanks well I sure missed that one, it’s on the same side of the road as well but on the other side of the railway bridge.

[bd139]

Holy crap now I've seen the picture I have actually been in there. Long time ago!

Did it have lots of clocks in it somewhere or is my memory playing tricks?

[nfmax]

spent about 1 hour on the phone with Quadral, the manufacturer of those vintage speakers (hand built in 1986 ... whoa ...)

Took out the crossover. While the capacitors still look ok, I cannot tell if they indeed are. Furthermore, the values are not at all what Quadral would want them to be.
They quoted: 130 instead of 70, 47 instead of 56, 1 instead of 4.2, 5.2 instead of 4.2 (all uF).

Now would be a great time to take out the LCR meter and just start checking coils, capacitors and resistors and then adapting the crossover to what they expect it to be.

Which is probably what I am going to do.

*sigh*

If the capacitors turn out to have lost their oompf, it would most likely make sense to replace all of them. After 34 years or so I would expect them to  no longer be up to specs.

Ah yes, that sounds like the result of a so-called 'upgrade' by some incompetent & opinionated Audio Expert at some point, especially given the weird values. The capacitors are probably OK, but that doesn't help if they are the wrong values.

I have a pair of QUAD ESL-63 electrostatics (built 1981) in daily use, still with mostly original capacitors - all the ones in the signal path, anyway. One HV PSU failed a decade or two ago. The design has a parallel RC network (1R5//220u) in series with the transformer primaries. The 'experts' used to love to remove this because obviously anything in series must be destroying the transparency of the sound, or some similar crap. IIRC it compensates for a slight shelf in the response beacuse of an acoustic effect, maybe when we switched from single side extrusions to separate inner and outer?

[Robert763]

While the capacitors still look ok, I cannot tell if they indeed are.

From the 1980s? It's safe to assume they aren't.

Why?
There is no real wear-out mechanisim for plastic film capacitors of this era. Apart from manufacturing defects or overloading there is no resaon for these to fail. Even the stacked plate ones that were sawn up and not encapsulaed don't seem to fail.
People seem to think that because Rifa sealf-healing caps and some electrolytics are known to fail that all capacitors will die.
The quality wound plastic film capacitors only real faiure is when they have been subjected to excessive voltage, dV/dt or current. These are unlikely in a crossover.
Don't tar all capacitors with th Rifa brush.

[bd139]

This weekend's task. So I have two counters. I know the racal is good as the guy who sold it actually run it up on a GPSDO for a couple of hours and adjusted it and it's got an OCXO on it. It'll be good to 1-2 Hz at least.

Now the HP has a crappy crystal oscillator in it which is drifting all over the place. So I've fired them both up and will leave them to warm up for a couple of hours and then monitor the reference output of the Racal plugged into the front of the HP.

[tautech]

Don't forget the counter function in the SDG you have coming. 

[bd139]

A question on that actually. Is it a piece of shit like the Rigol ones or is it actually usable?

(I know the connector is on its arse)

Edit: just checked datasheet. Same constraints (+/-2.5v p-p). I think that naff arse counter comes free with the chipset so I'll stick with the external counter

[tautech]

A question on that actually. Is it a piece of shit like the Rigol ones or is it actually usable?

(I know the connector is on its arse)

TBH not used one much but IIRC the Stats it offers can certainly be useful. It's only rated to 200 MHz and 5V max input.
Right outta 1032X ATM and just sold my 6022X  so can't pop any imagery here.
RTFM. 

[bd139]

Yeah I just did that ironically 

I just need a 2MHz dual channel FG at the moment that doesn't have a shitty user interface and can do some reasonable triggered bursts to be honest. I hope it works out 

Edit: everything seems to have settled here which I don't think I'm going to even quibble about



The 5316A xtal oscillator is much much better than the xtal one in the 5334B. That was horrid.

Edit: 1% selling fees on ebay over this weekend. Time to lose some crap 

[tggzzz]

Where in Mill Road, Cambridge was this H Gee's then, the only shops I can recall of interest in Mill Road was Cambridge Resale and Cash Converters, both were shops where poor students would take anything of value and sell / hock to meet their drinks / coke / rent debts and I managed to pick a few things of interest there years ago myself while I was living in Haverhill.

Google gives 94A Mill Rd, Cambridge CB1 2BD

[tggzzz]

Hahahahaha thank you 

One down, 20 million to go 

Those squirrel problems are spreading over here. My s.o. was bombarded by one with acorns just a few days ago.

One once bombarded me with sweet chestnuts, but most were too small to bother with eating.

[med6753]

Now it looks like my next project will arrive Saturday rather than Monday. Coming from Ohio via FedEx. I'll reveal when it shows up.

Not sure if I'll be on Discord tomorrow. Lady Copper arriving today for the weekend. But we have no plans other than to just hang out here. If I do log in I'll have to be on my best behavior.   

[BU508A]

This weekend's task. So I have two counters. I know the racal is good as the guy who sold it actually run it up on a GPSDO for a couple of hours and adjusted it and it's got an OCXO on it. It'll be good to 1-2 Hz at least.

Now the HP has a crappy crystal oscillator in it which is drifting all over the place. So I've fired them both up and will leave them to warm up for a couple of hours and then monitor the reference output of the Racal plugged into the front of the HP.

Tony? Is that you?

 

[syau]

All the RIFA or line filter gave out magic smoke when wife watch me playing the “toys” 

Yes, I know that there is high possibility for those RIFA giving up when plug into 220V supply after sitting most of their life in 115V environment, but the timing can’t be so coincident. 

[mnementh]

I hope you don’t end up with one of my locals on the other end 

Fortunately, the radio horizon from LEO is such that I doubt your locals would be able to be on when I'm on. 

Every time you hobos start talking about LEO, I have to catch myself... growing up in a hippie household, that  means something totally different, and the ol' dwagon hackles start to rise. 

mnem

Self referential? 


OK, OK I had to look this up on my favorite "save myself from embarrassment" website...Urban Dictionary. I am about as opposite as a hippie as you can get. But I can still laugh uproariously at the exploits of Cheech and Chong.

6-up, guys! Five-Oh next street over!

mnem
"All along the watchtower..."

"...Whatchoo gonna do when they come for yoooou...?"

Mmmhmmm... a younger mnem woulda tried to get one more toke in before they slap the cuffs on. 

mnem
 

[bd139]

Well it’s “is that crap from China real weekend”. Have got some laser transfer paper in so I can do some transmission line friendly PCB fixtures for the MAV-11SM MMICs I bought and the ADE-1-24 mixers.

Going to throw the MAV-11SMs at the NanoVNA and check gain over most of the BW of the device. Mixers will wait until the TinySA and SDS arrives.

Back to listening to conference calls while designing Kicad footprints 

[25 CPS]

...
Frig.  Frig.  Frig.   I thought GPs were supposed to be good about not leaking. ...

They are, leastways I've never had a problem with them. I have, however, a sneaking suspicion that they have gained a good enough reputation, and a high enough profile, that someone may have started counterfeiting them. My latest batch of GPs, bought from a different source than I usually get them from, have exhibited suspiciously low capacity.

I bought the meter used so I don't know how long the batteries were in there so they could've been sitting 'long enough', however long that was, to cause two of them to start leaking.  For that matter, with the origin of the batteries unknown, they could very well be knockoffs.  There are so many counterfeit products out there, I wouldn't be surprised if GP's batteries are being knocked off with convincing looking fakes that don't perform or don't stand up as well as the real things do.

Good luck on the 270. If you need anything for it, lemme know; odds are very low my 265 will be resurrected anytime soon, so better it should live on in another meter, at least for now. I had my fun cleaning it up & fixing the leather strap.

mnem
*knocks self unconscious with a shunt mallet*

I'll post some pictures once I get into those meters plus a couple of other pieces of gear that have sat for too long that I've been meaning to get to.  The pandemic + work has burnt me out pretty badly so I'm looking forward to turning the email auto responder on and my work phone off at 16:00 and having some quality time to do stuff that I enjoy.

[Specmaster]

Now it looks like my next project will arrive Saturday rather than Monday. Coming from Ohio via FedEx. I'll reveal when it shows up.

Not sure if I'll be on Discord tomorrow. Lady Copper arriving today for the weekend. But we have no plans other than to just hang out here. If I do log in I'll have to be on my best behavior.   

Of course, you'll have to be on your best behaviour or else the lady cop might just put her own cuffs on you, the not fancy but purely functional ones 

[mnementh]

While the capacitors still look ok, I cannot tell if they indeed are.

From the 1980s? It's safe to assume they aren't.

Why?
There is no real wear-out mechanisim for plastic film capacitors of this era. Apart from manufacturing defects or overloading there is no resaon for these to fail. Even the stacked plate ones that were sawn up and not encapsulaed don't seem to fail.
People seem to think that because Rifa sealf-healing caps and some electrolytics are known to fail that all capacitors will die.
The quality wound plastic film capacitors only real faiure is when they have been subjected to excessive voltage, dV/dt or current. These are unlikely in a crossover.
Don't tar all capacitors with th Rifa brush.

The problem is they are often difficult to identify; metallized paper axials look very similar, and confusion there adds to the body of evidence that all capacitors are suspect above a certain age. Add to that the fact that we don't know the exact chemistry of the plastics involved in those "old" plastic film caps, and there can be some properly placed misgivings about whether those plastics have begun to break down with age over the course of decades.

The problem with caps in general is that there is a fair measure of voodoo in their construction and application to the average electronics nerd; even engineers can be ignorant of things like how electrically fragile tantalum caps can be or how critical is the difference in derating curve for MMLCCs vs other types, how ESR vs ripple rejection ratings apply in a brute force filter, and how different kinds of caps in parallel can interact on a power rail vs signal path.

I'm certain there are easily a dozen other critical considerations as well that I'm just not thinking of;
I'm still right about here on my first cuppa.   

Bottom line is Tesla's ghost lives in each and every one of them; plus he's pissed off and a little bit crazy. You NEVER know when SOMETHING is gonna drive one over the edge. 

mnem
MAXIM # 9. Capacitors are Murphy's Footsoldiers.

[AVGresponding]

The quality wound plastic film capacitors only real faiure is when they have been subjected to excessive voltage, dV/dt or current. These are unlikely in a crossover.

Given the volume levels Saskia likely drives them at, I wouldn't count on it!   



Parcel day in HB, clearly. Picked up one from Hobby King at the Post Office, not TE I know but will be a lot of fun when I get my Tamiya Monster Beetle running with a new brushless motor/esc combo. 12T ftw... Should be good for wheelies off the line, assuming the tyres don't rip clean off the rims.   

TE delivery is the HP 66311B. You can tell it's an HP, because it appears to be made out of pure neutronium!   
It's 1/2 rack width, 2U high, full depth, and weighs 10kg if it weighs a gram. Fortunately the seller is an experienced TE dealer and it was extremely well packed.   
Teardown pics to follow this weekend, if I have time.



EDIT: Rather annoyingly the Hobby King parcel had been opened and not resealed. Because for some reason best known to themselves, HK stuck a Li-ion caution label on the package.
No batteries were present, of any chemistry.