Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

Often yes, but you don't, instead you gently work it back and forth getting it a little more and more. Gently gently is the secret and when it looks like the threads might bind some lubricating penetrant can save the day.

That is true for corrosion or sealant but not galling. Back and forth movment allows release of corrosion products but just promotes galling. It's actually the aluminium oxide layer that stops galling, working back and forth breaks that layer down and allows galling. Normal lubricants don't help much unfortunatly.
[/quote]
All true however every case is different. Tiny to and fro movements are what's required to help powder the corrosion products and create small clearances for lubricating penetrants to penetrate and help prevent further galling.

Most times I win but still get caught occasionally however the more tricks you have in the arsenal the more lucky you'll be.
Often stuck shafts like Med has are due to too finer manufacturing clearances and engineers don't do that on purpose, they do it in error as they never get to see their work decades later so to understand 'weathering/ageing' processes.
It's an art in itself freeing up frozen fasteners. 
[/quote]

I agree for corrosion products, but this is a case of galling not corrosion. The oxide film on aluminium is what prevents galling.
Obviously I'm making some assumpions here as I haven't inspected the actual item. But based on the photos and experience, both of this exact failure and years in the aircraft industry, I'm confident it's galling. 

[AVGresponding]

If this is as described (ie: used - previously owned but fully operational) and anyone is near to Chippenham (collection only) this is a bargain:  https://www.ebay.co.uk/itm/175177658083

[Robert763]

anything else you might use to solvent weld PMMA (Perspex).

What would one use to solvent weld Perspex? I realise there are suggestions in the text I cut, but I'd like to read your thoughts on that. I've tried CA for glueing it and been less happy. (It probably was application error; when I tried to glue two flat sheets together I got good results. When I tried to glue at an angle, it broke too easily; I'm assuming from less contact area, not straight pieces et c.)

You'd think that gluing Poly Methyl Methacrylate with methyl cyanoacrylate glue would be close to the perfect combination wouldn't you? PMMA and cured cyanoacrylate are almost the same plastic, and certainly have very similar physical properties. My experience has been the same as yours, total pants. I'm guessing it's a surface energy thing, like trying to join cold, set paraffin wax with hot liquid paraffin wax, they never truly fuse. Perhaps there's a primer that would make it work well, but those primers tend to be (a) very material/glue combination specific, (b) bloody expensive, and (c) difficult to find.

I've got some generic primer for low surface energy plastics for cyanoacrylate that's pretty good. It managed to stick PTFE to hard TPE rubber with CA glue - which is pretty impressive. Not a perfect, highly strong bond, but good enough to keep some 'skids' I'd cut out of PTFE sheet stuck to the bottom of the rubber feet of a steel framed chair that gets used every day for a year or two at a time. I have to re-stick them from time to time. I might give it an experimental try if I can find where my PMMA scraps have got to.

Methylene chloride used to be the standard for solvent welding PMMA, but chlorinated solvents have fallen out of favour (REACH and friends, much lower occupational safety limits, higher PPE requirements, and so on). It worked well, and with a bit of practice it was possible to produce invisible, optically clear joins that were as strong as the native material. Acetone will work, but is too fast evaporating to be really satisfactory; also there's more risk of solvent crazing.

Nowadays it is much easier to get proprietary solvent welding mixtures and I have to say that my experiences with them have been disappointing. Some of them must work well because people are still producing new display cases, aquaria and the like that look as good as ever, but the ones that I've tried haven't been up to snuff. Slower to gel the plastic, slower to dry, and don't seem to produce joints as strong, or as reliably. I've had to have a second try on failed joints on more than one occasion.

I've even had one mixture specifically sold for solvent welding PMMA that just didn't seem to work at all, and that was on a joint properly prepared for capillary solvent welding. I even tried joining two flat sheets with a lap joint (an essentially perfect surface for capillary solvent welding) just to see if it would work then, and all I got was a cloudy area on both pieces and a join with so little mechanical strength that it failed just from me picking it up from just one side of the joint. WTF?

Perspex^TM themselves recommend a range of acrylic adhesives and cements from Bostik sold under the Tensol® name for PMMA to PMMA bonding. For bonding PMMA to other substates they recommend a CA adhesive, specifically Bostik 7452 - go figure.

I agree entirely.

Look for EMA Plastic Weld from model supplies (+amazon and ebay)
www.jacksonsmodels.co.uk/ema-plastic-weld-suitable-for-most-plastics-57ml-ideal-for-evergreen-plastruct.ir
it's pure Methylene chloride with no dissolved plastic.

I use it all the time. With two flat polished PMMA blocks helh together a couple of drops on the edge makes a invisible joint.
It is also good for re-gluing welding the plastic cases of "soap on a rope" power supplies after you crcked them open to repair them.

[Vince]

While sorting through lots of really ancient stuff my old friend gave me... I excavated this thing. A 1MHz crystal oscillator...

That is a very nice oscilator, Oven controlled. Almost certainly designed to run of 24V so you can ramp it up a little. Let it warm up and watch the frequency when you gently set it on its side. One side should make the frequency go up, tilting over onto  the opposite side make it down.
This is the effect of a +_ 1G force of gravity change on the crystal.

Oh yeah, I remember Dave doing a video showing this effect, a few years ago. Was interesting 

Tried this morning, but sadly I can't reproduce it with this oscillator 

I guess my counter is not good enough. I used the longest gate time I have, 10 seconds, so I get 0.1Hz resolution, 7 significant digits.... but not good enough apparently.

With both the oscillator and counter starting from cold, initial measurement is 1,000,030+ Hz , dropping at a steady rate.
After only 10 minutes or so, it eventually reached equilibrium and was oscillating between 999,998 and 999,999 Hz.
From that point, I let it run for one hour, and still no drift, still  oscillating between 999,998 and 999,999 Hz.

So since it looked really stable, I thought OK I can make finer measurements now.
So I increased gate time to 10 seconds to get an extra digit. Was  oscillating between 999,998.2 and 999,999.3 Hz.

So then I laid the oscillator on it's right side, zero change, not one single count, nada... then put it on it's left side... same.
Then put it upside down, with it's feet/mounting base up in the air... still zero change.
I must say I was disappointed ! 
I guess I need a more fancy counter to detect this gravity effect, oh well 

If throwing it out thro it my way 

[Robot voice] " I am sorry Dave Robert, I can't do that ! "

You seeming interested in this thing means it must be a good piece... which brings extra mitivation to keep it !
Plus, you garage is full, and the only spot you could put it in the house, would be atop the fridge in the kitchen.
You trying to convince your wife it's a cool trendy ornament, would not be a convincing argument and she would ask for divorce.
I don't want to be responsible for that ! 

[Specmaster]

Someone give Spec a poke to remind him Discord today ! 

Hah, I spent last night trying to re-instate my NAS drives that the latest Window 10 fecked for me, still attempting recover them 

[Vince]

Vectron used to make boat anchor sized but nice rack mountable frequency measurement apparatus. You should poke around for a manual for your (ovened? 1 MHz frequency standard?) Or maybe ask on time-nuts@lists.febo.com if anybody there knows anything about it.

Vectron was a quality maker of test equipment in the 1950s and 1960s.

The pre-HP days.

Thanks for the info.

Yes it's a 1MHz oscillator as I mentioned earlier.

I did ask my old friend about this oscillator, and turns out he remembers it vividly !
It's not just some random junk he pulled from God knows where, no... he said it's regulated it's an OCXO, and was back in its day a top notch oscillator.
He actually was using this particular one as a Freq ref in his personal lab, and calibrated it at work using the fancy equipment he had there. He let it warm up for a week then trimmed it.

Luckily I did not mess with the trimmer ! 

He said he does have the datasheet for it somewhere, but his lab looks like Robert's garage so I don't think he will ever bother searching for it, and if he did, not sure he would manage to find it anyway... 

However from the top of his head he did remember that yes it was indeed a 24V nominal supply voltage, and that accuracy was 10-9.
... which is splendid for my personal use... means it is one order of magnitude more accurate than my 8 digit Nixie counters ! So I could use this oscillator to feed all my Nixie counters... I have two of them with 5 digits, and two of them with 8 digits. And since it is the same Vintage as these counters, it's 1MHz, which is what these old counters take. They don't take 10MHz. So it's plug and play ! 

So there you go, my first step in time nuttery, I have my first Freq ref !!! 

My friend said he can't remember what the output impedance is, and that I should measure it.

Hmmm.... could be one last fun experiment to do before I put it away and resume sorting components ! Stay tuned !!

[tggzzz]

If this is as described (ie: used - previously owned but fully operational) and anyone is near to Chippenham (collection only) this is a bargain:  https://www.ebay.co.uk/itm/175177658083

Blasted enablers; I hate you all.

I'm picking it up tomorrow, after testing.

Anybody want a Tek 2467? https://www.ebay.co.uk/itm/165357463536

[Vince]

Welcome to the 2467 club ! 

For 99 pounds you can't go wrong... if it's a turd you can flog it for parts again, for more than you paid for it... and if it can be fixed then well keep it and be happy you got such great deal ! 

Of course the cynic in me can't help but think the seller very well knows it's cooked and is playing dumb but... who knows, maybe he is actually clueless and you got a winner for a song, crossing fingers  !

Looking forward to you testing it and troubleshooting it....

EDIT : Oh, you said you would be able to test at sellers before making a decision... good.
However the two major, show stopper problems on these scopes only manifest itself at the very fastest sweep speeds... you would need to bring with you a 500MHz pocket oscillator with you.

But anyway again, for 99 quid you just can't go wrong regardless of the scope's condition...

[tggzzz]

Welcome to the 2467 club ! 

For 99 pounds you can't go wrong... if it's a turd you can flog it for parts again, for more than you paid for it... and if it can be fixed then well keep it and be happy you got such great deal ! 

Of course the cynic in me can't help but think the seller very well knows it's cooked and is playing dumb but... who knows, maybe he is actually clueless and you got a winner for a song, crossing fingers  !

Looking forward to you testing it and troubleshooting it....

EDIT : Oh, you said you would be able to test at sellers before making a decision... good.
However the two major, show stopper problems on these scopes only manifest itself at the very fastest sweep speeds... you would need to bring with you a 500MHz pocket oscillator with you.

But anyway again, for 99 quid you just can't go wrong regardless of the scope's condition...

I'm buying the Keithley 2015, not the scope.

I'm going to exhibit restraint w.r.t. the 2467, and make do with my herd of 485, 2*2465, 1740, ..... If I don't exhibit restraint, I would feel compelled to go and pick it up so as to avoid packaging and couriers "opportunities".

[Vince]

Oh I see, crap ! 

You fooled me..... saying "I am picking it up tomorrow " then just below, the pic of a 2467 ! 

[factory]

Vectron used to make boat anchor sized but nice rack mountable frequency measurement apparatus. You should poke around for a manual for your (ovened? 1 MHz frequency standard?) Or maybe ask on time-nuts@lists.febo.com if anybody there knows anything about it.

Vectron was a quality maker of test equipment in the 1950s and 1960s.

The pre-HP days.

Confused by that last comment, did HP not make any TE in the 1950s or earlier?   

Thought I had seen a Vectron oscillator from something HP, it's part of a 8640 (option 323 military version) board, bought from a well known test equipment scrapper on ePay.de a few years ago.


David

[factory]

Thought about bidding on this lot, but have worked out the K05-5340A is a replica*, so someone might have a pile of blank PCBs, which would be cheaper to send.
https://www.ebay.co.uk/itm/284662057463





*See if you can spot the assembly/design? error. 

David

[Vince]

Vectron OCXO : just measured the output impedance... first loaded it with a 20K pot, had to turn it all the way down to half the output voltage.
So picked a 470R pot, much better, could get fine control around the half-voltage mark.  So, it appears the impedance is... 220R.

I notice that the current draw is much less now... was 210mA from cold, but now that's it's been running for 5 hours or so, it's evenly warm to the touch, and it's now taking only 125mA or so.


OK now putting it away and reclaiming bench space for component sorting duties.

[Vince]

Thought about bidding on this lot, but have worked out the K05-5340A is a replica*, so someone might have a pile of blank PCBs, which would be cheaper to send.
https://www.ebay.co.uk/itm/284662057463





*See if you can spot the assembly/design? error. 

David

Other than the solder job that leaves me baffled with most joints not having any solder at all, or only half what they need, you mean ?! 

Other than that then, it looks like he used a 110R resistor instead of 240R ? Or if the colours are a bit off and what I see as brown is rather, some shade of dark red... then that would make it 220R instead... but that's still not 240R...

[TERRA Operative]

Thanks for the info.

Yes it's a 1MHz oscillator as I mentioned earlier.

I did ask my old friend about this oscillator, and turns out he remembers it vividly !
It's not just some random junk he pulled from God knows where, no... he said it's regulated it's an OCXO, and was back in its day a top notch oscillator.
He actually was using this particular one as a Freq ref in his personal lab, and calibrated it at work using the fancy equipment he had there. He let it warm up for a week then trimmed it.

Luckily I did not mess with the trimmer ! 

He said he does have the datasheet for it somewhere, but his lab looks like Robert's garage so I don't think he will ever bother searching for it, and if he did, not sure he would manage to find it anyway... 

However from the top of his head he did remember that yes it was indeed a 24V nominal supply voltage, and that accuracy was 10-9.
... which is splendid for my personal use... means it is one order of magnitude more accurate than my 8 digit Nixie counters ! So I could use this oscillator to feed all my Nixie counters... I have two of them with 5 digits, and two of them with 8 digits. And since it is the same Vintage as these counters, it's 1MHz, which is what these old counters take. They don't take 10MHz. So it's plug and play ! 

So there you go, my first step in time nuttery, I have my first Freq ref !!! 

My friend said he can't remember what the output impedance is, and that I should measure it.

Hmmm.... could be one last fun experiment to do before I put it away and resume sorting components ! Stay tuned !!

Nice score.
I always pull the OCXO's from scrap equipment. I used one to upgrade my Tek DC503A with a homebrew optional upgrade. (I made a youtube video on it a while back).
The other I'm making into a USB powered 'pocket' reference for fun and youtube.

I splurged on the Leo Bodnar GPSDO, so everything in my lab is referenced to that.

[Cerebus]

The last time this happened, it was a defrosting element gone leaky - which cost half an arm to fix

That, and defrosting elements going open circuit, seems to be the primary failure modes for modern "frost free" domestic refrigerators. They have a laughably short lifetime compared to old fashioned "defrost it yourself you lazy bastard" fridges. My mother was using the same fridge when she moved out of the old family home as we had when I was a child, easily a 40-50 year life and still going when she moved to sheltered accommodation necessitating the abandonment of the still working fridge.

We had the defrosting element go open circuit on our fridge freezer perhaps 10 years back when the fridge freezer was only a few years old. Fortunately it had failed at one end only so I could fix it. It failed again, this time somewhere far enough into the tube that contains the defrost element that I couldn't get at it, so for years since it has been used as a "defrost it yourself you lazy bastard" fridge freezer. It has lasted longer in that mode than it did up until its first defroster failure.

The defrost heater on ours (a Samsung) was made with some kind of tinsel wire. Now call me a cynic, but that's not what I'd pick for a resistance heating element if I wanted it to have a long life. On the other hand, if I wanted it to fail after a few years service that's exactly what I'd choose.

[TERRA Operative]

Thought about bidding on this lot, but have worked out the K05-5340A is a replica*, so someone might have a pile of blank PCBs, which would be cheaper to send.
https://www.ebay.co.uk/itm/284662057463





*See if you can spot the assembly/design? error. 

David

I made a version of this along with the riser card, I might have one spare set left, maaaaybeeeee.

Do you need it if I can find it?

[EDIT] Found them. I also have a replica unpopulated PSU board for the OCXO option too if you want me to throw that in too.

[Cubdriver]

Thought about bidding on this lot, but have worked out the K05-5340A is a replica*, so someone might have a pile of blank PCBs, which would be cheaper to send.
https://www.ebay.co.uk/itm/284662057463





*See if you can spot the assembly/design? error. 

David

Electrolytics are in series + to - rather than in opposition + to + as they are in the schematic?

-Pat

[mnementh]

If throwing it out throw it my way 

[Robot voice] " I am sorry Dave Robert, I can't do that ! "

You seeming interested in this thing means it must be a good piece... which brings extra mitivation to keep it !
Plus, you garage is full, and the only spot you could put it in the house, would be atop the fridge in the kitchen.
You trying to convince your wife it's a cool trendy ornament, would not be a convincing argument and she would ask for divorce.
I don't want to be responsible for that ! 

   BWAHAHAHAHA!!!

Now you're starting to sound like a certain crusty ol' tinkerdwagon. Do I need to worry you're going to start wearing scales and develop a unnatural relationship with fire...? 

mnem

[mnementh]

If this is as described (ie: used - previously owned but fully operational) and anyone is near to Chippenham (collection only) this is a bargain:  https://www.ebay.co.uk/itm/175177658083

Blasted enablers; I hate you all. I'm picking it up tomorrow, after testing.

Anybody want a Tek 2467? https://www.ebay.co.uk/itm/165357463536   

*wibble*   

Does not ship to US.   

mnem
*sigh*

[Vince]

Next advice please.

Still from the same old friend... got these 4 EMI line filters. 5 amps, 40 years old according to date codes (ranging from 1981 to 1983).
50x50mm by 28mm thick/high.

Can old filters be trusted, I mean the caps in them, or should I play it safe and throw them away ?

Sticker gives no internal schematic but assuming the usual layout, I tested them blind, and it seems for now at least, that they have not failed... but might explode I guess first time I power them up... so is it worth it...

Inductance between input/output is about 100uH.

Y caps measure about 7nF, and X cap about 3nF.

According to the markings, they are made by ' SAE '.

Looked them up, still in business today. They claim to be making top notch filters for industrial use, medical blah blah blah, since the early '70s.

https://www.saepower.com/emirfi-filter-products/

Might just be marketing BS, it's free to talk.
I am sure if I go to RIFA's website they will claim the same thing as SAE...


So are they worth keeping, or just ticking time bombs and my life is worth more than a few old EMI filters ??

[Vince]

If throwing it out throw it my way 

[Robot voice] " I am sorry Dave Robert, I can't do that ! "

You seeming interested in this thing means it must be a good piece... which brings extra mitivation to keep it !
Plus, you garage is full, and the only spot you could put it in the house, would be atop the fridge in the kitchen.
You trying to convince your wife it's a cool trendy ornament, would not be a convincing argument and she would ask for divorce.
I don't want to be responsible for that ! 

   BWAHAHAHAHA!!!

Now you're starting to sound like a certain crusty ol' tinkerdwagon. Do I need to worry you're going to start wearing scales and develop a unnatural relationship with fire...? 

mnem

No don't worry no way I am going to turn into a dragon anytime soon !

It's just not who I am deep down...

No competition to be scared of from me anytime soon, you are the one and only dragon on here, rest assured ! 

[mnementh]

...However from the top of his head he did remember that yes it was indeed a 24V nominal supply voltage, and that accuracy was 10-9.
... which is splendid for my personal use... means it is one order of magnitude more accurate than my 8 digit Nixie counters ! So I could use this oscillator to feed all my Nixie counters... I have two of them with 5 digits, and two of them with 8 digits. And since it is the same Vintage as these counters, it's 1MHz, which is what these old counters take. They don't take 10MHz. So it's plug and play ! 

So there you go, my first step in time nuttery, I have my first Freq ref !!! 

My friend said he can't remember what the output impedance is, and that I should measure it.

Hmmm.... could be one last fun experiment to do before I put it away and resume sorting components ! Stay tuned !!

Of course, you cannot put it away until you've built it into a enclosure with a distribution amplifier and a nice low-noise linear power supply...

...Built using one of those transformers you couldn't decide  to do with.   

mnem

[tggzzz]

If this is as described (ie: used - previously owned but fully operational) and anyone is near to Chippenham (collection only) this is a bargain:  https://www.ebay.co.uk/itm/175177658083

Blasted enablers; I hate you all. I'm picking it up tomorrow, after testing.

Anybody want a Tek 2467? https://www.ebay.co.uk/itm/165357463536   

*wibble*   

Does not ship to US.   

Send him a message mentioning GSP? Check he knows how to pack a scope

[Cerebus]

Next advice please.

Still from the same old friend... got these 4 EMI line filters. 5 amps, 40 years old according to date codes (ranging from 1981 to 1983).
50x50mm by 28mm thick/high.

Can old filters be trusted, I mean the caps in them, or should I play it safe and throw them away ?

Sticker gives no internal schematic but assuming the usual layout, I tested them blind, and it seems for now at least, that they have not failed... but might explode I guess first time I power them up... so is it worth it...

Inductance betweden input/output is about 100uH.

Y caps measure about 7nF, and X cap about 3nF.

According to the markings, they are made by ' SAE '.

Looked them up, still in business today. They claim to be making top notch filters for industrial use, medical blah blah blah, since the early '70s.

https://www.saepower.com/emirfi-filter-products/

Might just be marketing BS, it's free to talk.
I am sure if I go to RIFA's website they will claim the same thing as SAE...


So are they worth keeping, or just ticking time bombs and my life is worth more than a few old EMI filters ??

You could power them up on the mains using a suicide cord. Experience says that if they are going to go it is within the first 15 minutes of having power applied. Needless to say, do this outside, unless you like the gentle scent of Eau de Rifa attached to all your clothing and soft furnishings for months to come.