Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Good point about deleting posts. Very sneaky 

   

Now where's 80 year old stripper?

   You rang? Here's your prize. 

That's it. I warned you, mutherfucker.   

*presses [BIG RED BUTTON] *



mnem

You bastard, I almost choked on my coffee when I saw that. 

[URI]

After having powered up, and listened to, the 53132A for the first time in a good few days I'm of the opinion that it needs a fan-ectomy.

Current fan is a Delta DBF0412M: 40 x 40 x 10 mm, 12VDC and 7.17 cfm. Anybody got any suggestions for a quiet(er) replacement, or should I just get another Delta?

N.B. Having a fancy OCXO this is one of the "If it's plugged in it's on standby" HPs, so the fan is always on when the power lead's there, therefore it wants to be as quiet as possible.

Have a look at sunon maglev fans. They tend to have very low mechanical hum sound.

I replaced the OEM fan of my 53123A with a NB Noise Blocker fan -but I can't say what exact type.
It's not really a noise blocker because it still has a noticeable mechanical hum.   

I'll replace that "noise blocker" fan some day but there's no pressure on me -my GPSDO is running 24/7 and doesn't even have a fan -and all my attached counters, intervall counters, synthesizers and frequenzy/function generators are accurate to the accuracy of my GPSDO right from power on. 

So you might consider that..   

[Wolfgang]

After having powered up, and listened to, the 53132A for the first time in a good few days I'm of the opinion that it needs a fan-ectomy.

Current fan is a Delta DBF0412M: 40 x 40 x 10 mm, 12VDC and 7.17 cfm. Anybody got any suggestions for a quiet(er) replacement, or should I just get another Delta?

N.B. Having a fancy OCXO this is one of the "If it's plugged in it's on standby" HPs, so the fan is always on when the power lead's there, therefore it wants to be as quiet as possible.

Watch out for a gotcha: OCXOs are vibration sensitive. Quietness is fine, but perfect bearings are also important. Test: measure phase noise (1Hz-1kHz) with fan on and off.

[Cerebus]

After having powered up, and listened to, the 53132A for the first time in a good few days I'm of the opinion that it needs a fan-ectomy.

Current fan is a Delta DBF0412M: 40 x 40 x 10 mm, 12VDC and 7.17 cfm. Anybody got any suggestions for a quiet(er) replacement, or should I just get another Delta?

N.B. Having a fancy OCXO this is one of the "If it's plugged in it's on standby" HPs, so the fan is always on when the power lead's there, therefore it wants to be as quiet as possible.

Watch out for a gotcha: OCXOs are vibration sensitive. Quietness is fine, but perfect bearings are also important. Test: measure phase noise (1Hz-1kHz) with fan on and off.

The buggers are everything sensitive - vibration, temperature, gravity, whether you're looking at them in a funny way...

For most fan speeds vibration and noise are synonymous. Most fan noise that isn't 'whitish noise' from air moving is conducted mechanical noise that comes out through the enclosure vibrating to the fan motion. So hopefully noise reduction is the same as vibration reduction. Personally the fan noises that I find most distracting are the ones that are likely to be mechanically conducted - the whining and scraping noises.

[bd139]

After having powered up, and listened to, the 53132A for the first time in a good few days I'm of the opinion that it needs a fan-ectomy.

Current fan is a Delta DBF0412M: 40 x 40 x 10 mm, 12VDC and 7.17 cfm. Anybody got any suggestions for a quiet(er) replacement, or should I just get another Delta?

N.B. Having a fancy OCXO this is one of the "If it's plugged in it's on standby" HPs, so the fan is always on when the power lead's there, therefore it wants to be as quiet as possible.

It’s the same as the 33120A fan. The noise is unfortunately not dependent on the fan but the holes in the back of the case. I bought a really quiet one for my old 33120A and it was noisy the moment it went in the case 

This is one reason I own a fanless arb and a fanless counter. In fact the only thing I can stand fan wise is the tek 4xx fans (when they’re not bashing on the back of the grille )

[Robert763]

Update on the HP 3335A synth / level generator. After a long soak  everything is working OK. So I've put all the screws in the mother board screened modules and put it back together. Three more photos, Mother board stood up, in postion and front panel. The bles on the mother board (except for the  output rigid coax) are long enough to lift the whole assembly out with it still connected.
All working well and a keeper as it adds high precision level generation to my TE capability.
 

[factory]

As for the switches... why resist...? I bought them cuz I needed 6 of the metal ones to fix that curb-score Samsuck TV; and we both know there's no way in hell the rest of the kit will go unused in any of our labs. For 10 bux, a total no-brainer.

EDIT: I'm bringing this to a new post as it really just made a dog's breakfast of the "cheap switches" conversation, and is actually something that's ON-TOPIC for a change.

That reminds me... this TV had the weirdest failure mode; I actually meant to post aboot this when it happened, but IRL (and the fact I lost the pics from when I was working on it) got in the way.

After the usual decontamination with shop rags and alcohol, I put the TV in the LR to use as our daily driver, as I've found that usually brings Murphy a-runnin' and is the best way to catch consumer electronics actually fucking up. 

It worked fine for a few days, then started randomly flicking from input to tuner, then randomly changing channels, or input to input, and argued with me aboot which input I chose when I tried to put it back. Turned out there was crazy noise on the IR sensor signal line, but not on the 5V rail that fed it. Further investigation with my 54645A showed the same noise on the signal line from the front keypad (which shared a ribbon cable with the IR sensor to the uPC), only at higher amplitude. Unplugging the keypad made it go away.

The weird bit was that there were no actives on the keypad; just the tactile switches and pulldown resistors of various values to let the uPC know which button was pressed per the voltage on the line. 

I ran out of time at that point due to IRL, so popped the cover on the back and just used the TV for a week with the keypad removed. After confirming the problem gone, I got around to visually inspecting every solder joint and testing every switch/resistor on the board, and they all tested right on. Next diag session I plugged it back in and was getting crazy voltage readings; probing the keys with my scope showed noise which changed just from moving or tapping the board. On a board with zero active components. And shouldn't have any closed circuits.

After staring at the fukkin' thing and scratching my head for aboot 10 minutes, I went to visit the porcelain throne (like many of us, I seem to do my best cogitatin' there ); during my visit it occurred to me there might be a intermittent short/contact in one or more of the tactile switches.

Went back to it and looked at the switches under a magnifier, and whaddayooknow... the top tin part just pops off. So I opened 'em all up and inspected, expecting to find a bit of dirt or rust inside one. What I found was actually much stranger.

On three of them, the silvering on the contacts had migrated ( I assume from electrolysis) such that it formed a very visible spiderweb of metallic tendrils across the surface of the plastic body (these appear to be made of some filled nylon or resin plastic) of the switch between the contacts. This didn't actually appear to have continuity on the one I removed for testing, but it did have measurable resistance and capacitance if I put the silver-plated dome cup back in place.

Having figured this out, I carefully scraped/cleaned all the switches with alcohol to remove the silver deposits and reassembled the TV with the PCB installed; the noise was gone on both data/signal lines, and it worked flawlessly until aboot a month or two ago, when I bought those switches and just replaced them all.

My best surmise is that moisture in the air promoted the electrolysis/silver deposition due to the constant 5VDC applied; once it got to a certain point the physical structure of the switch became a LC and/or RC oscillator. Now have 2 or 3 of them doing that at the same time and... batshit crazy TV.

mnem
 

I had the very same fault in my Samsung, although it originally manifested itself iin a different way.
After working well for years (I bought it new), for some forgotten reason, I wanted to feed it with the VGA & sound outputs of my laptop.

Just my luck, ----the remote croaked!
"No wuckers"*----------I'll just use the switches on the side of the TV!
I set the switch to "computer" & away I went.

After much happy watching on the big screen (although it showed up how cruddy the VGA resolution was!), I returned the TV to normal service, & initially, all was well, but a problem arose, in that, after a while the bloody thing would return to "computer" input.

Over time, it got worse, & would randomly switch to other modes.
Digging around in the back with the 'scope was inconclusive, but eventually we obtained another remote, so I just unplugged the connection to the side switch, & used that.

*The derivation of this term is probably self explanatory, but if not, I'm not going to explain it on a family friendly forum.

That explains why a co-workers no-name-Sam* TV kept changing volume all by itself, it was barely used as it was in a static caravan, where he would go at the weekend/holidays when the weather was good, said TV eventually got dumped in the trash.
Ironically he passed a Vestel CRT set my way, this still works fine. Well apart from the degauss thermistor that cracked & arced, not really an issue as I had some spares, from lots of scrapped computer monitors.

*old insult for Samsung found in the comments of youtube.
 
David

[Cerebus]

After having powered up, and listened to, the 53132A for the first time in a good few days I'm of the opinion that it needs a fan-ectomy.

Current fan is a Delta DBF0412M: 40 x 40 x 10 mm, 12VDC and 7.17 cfm. Anybody got any suggestions for a quiet(er) replacement, or should I just get another Delta?

N.B. Having a fancy OCXO this is one of the "If it's plugged in it's on standby" HPs, so the fan is always on when the power lead's there, therefore it wants to be as quiet as possible.

It’s the same as the 33120A fan. The noise is unfortunately not dependent on the fan but the holes in the back of the case. I bought a really quiet one for my old 33120A and it was noisy the moment it went in the case 

This is one reason I own a fanless arb and a fanless counter. In fact the only thing I can stand fan wise is the tek 4xx fans (when they’re not bashing on the back of the grille )

Following on from by earlier remarks, I think that most of the fan noise in the mid-late era HP kit is mechanically coupled into the case. The 53132A gets quieter if you dump something on the case to damp it, ditto my power supplies of that era with fans. The slightly later 34461A has the same cutout where the fan is, but the case is much more rigid than the earlier cases and the fan noise is almost unnoticeable. I might experiment with some compliant mounts to see if that improves things.

[bd139]

Ok actually checked the Tek 475 out properly. Found my AWG and unpacked it again and hooked it up.

Absolutely bang on calibration. All attenuator settings work on both channels, triggering is perfect, timebase is spot on.

Leaving it to burn in for 6 hours today so far and it has been absolutely fine. Get the feeling this one hasn’t been used that much. Plus it’s a very late model one which means it has less cursed bits in it 

[mnementh]

Wow... you really like to taunt Murphy, doncha bd...? 

mnem
must be bored...

[RolandK]

The 100k history manipulation resembles me to the matrix where they just manipulated the building. Even the cat came twice. It just was a 80 year old two feet variant
This is the original scene:
https://youtu.be/XfEuxRDYiyc

[factory]

I must say I am kinda surprised and disappointed at how few " 4000 " TEA pictures we got, was expecting much more than that !

However...  I am not worried the slightest bit about the 100.000th post, it will trigger a tsunami of pics !!! Can't wait to see what people will come up with ! 


EDIT : OH no fuck me, it's me again and I did NOT even do it on purpose !! It's all your fault, posting while I was composing this very message !!!

Now I am under an obligation to come up with a 100.000 TEA pic and I just don't have the technical means to do it ! 

Not that it's relevant now it's long past 100k (passed by while I was at work), but doesn't your Metrix counter have a manual count function? i.e. you could display any number, up to the limit from the number of digits available.

David

[tautech]

So we're now in the 4000's and no one has posted pics of appropriately numbered CMOS IC's. 

[Cerebus]

Lowest numbered I've got is a 4053, and even that's a cheat, it's a 74HC4053.

[bd139]

Wow... you really like to taunt Murphy, doncha bd...? 

mnem
must be bored...

Baiting Murphy is my entire point in existing. Then kicking him in the balls

[tautech]

Lowest numbered I've got is a 4053, and even that's a cheat, it's a 74HC4053.

4001-4538 here. 

[Andrew_Debbie]

So we're now in the 4000's and no one has posted pics of appropriately numbered CMOS IC's. 

Ready to shotgun the Dana 5100, which is still flashing 200000     

[tggzzz]

Wow... you really like to taunt Murphy, doncha bd...? 

mnem
must be bored...

Baiting Murphy is my entire point in existing. Then kicking him in the balls

I believe that is mutual.

[bd139]

Get him before he gets you

As for 4000 series, CD4007UBE is the interesting one of the series

https://www.electronicdesign.com/technologies/analog/article/21754492/whats-all-this-cd4007-stuff-anyhow

[factory]

So we're now in the 4000's and no one has posted pics of appropriately numbered CMOS IC's. 

I could do, but can't be bothered trying to get to this rack full of 4000 series IC's (or the other one with Motorola 14000 series), don't think I've used a single one of them* since this crappy picture was taken in a hurry (during unloading), it took me three evenings to move all the stuff I bought from work component room in Jan 2019, about six months after they EOL'd the lab. 


*the 74 series on the other hand has proved very useful, used one of the 7490 IC's last weekend to fix the Bradley scope calibrator, I haven't moved the pictures from my phone and I don't won't to repeat being late for work tomorrow, so this old picture will have to do. 


David

[bd139]

Holy crap - whyyyy 

https://www.ebay.co.uk/itm/174913006204

[Saskia]

Rats. Low ball offer for a toothpick knife was not accepted ...

Won't be bidding more than 2300 quid.

@mnem: one for you.

https://www.messerkoenig.at/produkt/bathleth/

this is actually made from D2 steel, dew-picked and flown from Iraq, cleansed in the finest quality spring water, ...

[Vince]

I must say I am kinda surprised and disappointed at how few " 4000 " TEA pictures we got, was expecting much more than that !

However...  I am not worried the slightest bit about the 100.000th post, it will trigger a tsunami of pics !!! Can't wait to see what people will come up with ! 


EDIT : OH no fuck me, it's me again and I did NOT even do it on purpose !! It's all your fault, posting while I was composing this very message !!!

Now I am under an obligation to come up with a 100.000 TEA pic and I just don't have the technical means to do it ! 

Not that it's relevant now it's long past 100k (passed by while I was at work), but doesn't your Metrix counter have a manual count function? i.e. you could display any number, up to the limit from the number of digits available.

David

Hey yes that's an idea ! 

The meter is a bit convoluted / awkward to use... had to dig out the user manual to understand how to set all teh switches to get it to count, and what to do with the 2 dedicated gates/inputs and their associated switches..... Manual of course was burried at the very bottom of big plastic box full of stuff, had to empty it all all over the place just to get to the manual, thank you very much ! 

Well, so it turns out I can just press a button to count pulses... I need to feed one of the gates / inputs with a clean digital pulse start/stop signal, into a 50ohm BNC. So not exactly the most convenient of things for manual operation ! 

So I need to DIY something to that effect... bread board, a switch, power supply, and some debouncing circuitry. Doubt a simple RC circuit would be reliable enough, so would have to add a Schmitt trigger but how I don't know... will have to search through my collection of TTL chips, maybe there is a Schmitt trigger gate somewhere...   or roll my own with an op-amp, if no other choice.

Anyway need to sort it all out but definitely want to do it, so stay tuned ! Hopefully the pulse counting functionality of that counter works at all ! I have no idea since I never used it before ! Let's say it does work, crossing fingers....

[mnementh]

Holy crap - whyyyy 

https://www.ebay.co.uk/itm/174913006204

My guess would be:

Labeled Daystrom Institute

Original Manual in decent shape

lens not cracked or crazed from age

face anodizing crisp and clean

bakelite bits don't look like hammered shit

In other words... a good example of the breed in good nick.

mnem
 

[BU508A]

Page 4004, eh?

Not mine (from the German Wikipedia page):