Test Equipment Anonymous (TEA) group therapy thread

[med6753]

Started assessing/cleaning the Tek Type 105. As near as I can tell this thing is a virgin. It has never had any repair work or any sign of Gorilla activity. So I will be the one to bust it's cherry.  Behind that upper cover resides a half dozen metal 6AG7 tubes.  Been many years since I've seen metal tubes.



The fan motor required complete disassembly and oiling to free it up. Spins nicely now.



I removed the four 5V4G rectifier tubes. As soon as I round up a replacement fuse holder from my parts stash I want to power up the transformer with no B+ to insure it's secondaries are OK. Also test the filaments on all the tubes. This unit will not see full power up until all the electrolytics are replaced. Yes, there are a lot of them. But the vast majority are dual can 20uf/20uf wired in parallel along with other dual can 20uf/20uf in parallel. So I can combine the total capacitance into one capacitor.



As far as the tubular capacitors are concerned. The brown epoxy caps almost never go bad. I have other Tek equipment with loads of them and I've never had a defective one. So they will stay. The black tubulars are made by Aerovox. I've never known Aerovox to make anything other than cheap consumer grade wax crapacitors that turn into resistors in no time. So I'm highly suspicious of these caps but they definitely look like a higher grade than the consumer crap. So for now they stay. But if even one of them proves leaky they will all go into the trash.

 

[Vince]

[..] the electrolytics are replaced. Yes, there are a lot of them. But the vast majority are dual can 20uf/20uf wired in parallel along with other dual can 20uf/20uf in parallel. So I can combine the total capacitance into one capacitor.

Well lucky you, that's quite convenient isn't it...

As far as the tubular capacitors are concerned. The brown epoxy caps almost never go bad. I have other Tek equipment with loads of them and I've never had a defective one. So they will stay. The black tubulars are made by Aerovox. I've never known Aerovox to make anything other than cheap consumer grade wax crapacitors that turn into resistors in no time. So I'm highly suspicious of these caps but they definitely look like a higher grade than the consumer crap. So for now they stay. But if even one of them proves leaky they will all go into the trash.

I have not restored all my 20+ glowing Tek scope of course just yet, but from the few I have looked into, I would concur.

The only ones that really are really problematic, statistically, are the Sprague ones, with the black body and the red markings. Usually go bad in the CRT HV oscillator section, so when I replace those I replace them throughout the scope at the same time. All the others, with more colourful bodies, never had a problem with them.

[Vince]

n // I am working on the bedroom. Just finished fitting the parquet, glued. Now need to oil it. Waiting for the oil to com in, then need to find a company that can rent me the machine to apply it properly.

I've never even heard of someone using a machine to oil a wood floor. Perhaps they do for massive areas, but at domestic scale? For an area that small surely it's quicker and easier to just get out a rag and get onto your hands and knees?

Using the machine is standard here. Unless you are masochistic, there is no reason to inflict doing it by hand. Machine does a much better job, much more consistent, much faster, much less sweat, and saves the little that's left of my knees. We call it "monobrosse" here....
Even for my small 10m2 bedroom I hardly contemplate doing it by hand and knee.  YMMV of course... to each their own !

Cerebus' standard warning about drying oils

This is folk knowledge that tends to get passed from hand to hand but for some reason is never printed as a warning on cans of drying oils used for oiling wood.

(If you already know this please ignore, but I always post this in any discussion of drying oils becuase some people don't know this, and knowing it may save a life.)

Drying oils such as Danish Oil, Tung Oil, Linseed Oil and the like can spontaneously catch fire. Rags that have been used to apply drying oils, and that still have drying oils left on them can catch fire just from being left in the open air.

The mechanism is that the increased surface area of the oil exposed to air by being soaked into a rag causes a lot of the oil to 'dry' at once. This generates heat. The heat causes the oil to 'dry' (oxidise) faster. This makes more heat, which makes the oil dry faster - you know how this one goes, it's the classic chain reaction. The heat, combined with the insulating effect of the rag's cloth can be enough to cause the rag to catch fire.

The same applies to any material such as newspaper or paper towels used to mop up spills of drying oils or used to remove excess oil from workpieces.

When using drying oils on rags and cloths always handle the rags/cloths appropriately when you have finished with them. Either thoroughly wash out rags before disposal or storage, or soak them in water and place them inside an airtight bag or container. Do not leave rags and cloths unattended for long periods (e.g. over lunch) without taking appropriate precautions to prevent them possibly catching fire, or putting them somewhere that a possible fire will not present a hazard and will be contained.

[/quote]

Yes, the manufacturer does warn about it on his web page.
I am buying this top notch stuff (used by many profesionnal fine wood worker/ artisans), " RUbio ", made in Ice-Tea in Belgium :

https://www.acheter-rubio.fr/nettoyage-entretien-finitions-bois-interieur/10-170-metallisant-universel.html#/54-conditionnement-100ml_environ_15m

At the bottom of the product description, they clearly warn people to soak their oily rags immediately with water, once they are done with the job, before throwing them in the trash, to keep them from self-igniting and combusting :

"  Toujours mouiller les consommables (chiffons, éponges, pads, ...) directement après l'application et avant de les jeter pour éviter tout risque d'auto-inflammation. "

[Vince]

What's in the box(es) ??

Just picked them up. The bench is not really useable of course, still sorting through my stuff... will need to push some stuff on the side to make a tiny bit of room to plug it see if it works.

Hints : it's heavy, it's old (though that's subjective I guess... ) and the stuff in the small box is made to go with the stuff in the big box, they go along.

Sorry can't say more. You get what you get (and you don't get upset).

Reveal in an hour or two once I manage to find a space to unpack it, and make a bit of space on the bench somehow to power it up and give it a quick test ride.

[nfmax]

“What has it got in its cardboard boxes?”

[m k]

What scope maker used yellow and blue knobs?
https://www.leboncoin.fr/bricolage/2117578355.htm

Would it be a blasphemy to convert GOS-935 to a power supply?
https://www.leboncoin.fr/equipements_industriels/2077356723.htm

Last is few Tek plugins.
https://www.leboncoin.fr/equipements_industriels/2117534901.htm

[AVGresponding]

@factory, did you grab that TDR? I noticed it went for a fair bit over the opening bid.



Seem to be a lot of low-end scopes on sale today, from the usual suspects.

[Vince]

What scope maker used yellow and blue knobs?
https://www.leboncoin.fr/bricolage/2117578355.htm

Probably a manufacturer that went under 2 weeks after the scope going for sale, as nobody would buy such an horror I guess.... 

Would it be a blasphemy to convert GOS-935 to a power supply?
https://www.leboncoin.fr/equipements_industriels/2077356723.htm

It looks so crap and cheap that I think you are allowed to do anythign with/to it and nobody would blame you ! 

Last is few Tek plugins.
https://www.leboncoin.fr/equipements_industriels/2117534901.htm

Yes I saw these. I know the seller, I bought my Tek 575 curve tracer from him last summer. When I visited him I saw this very collection of plug-ins. Most are not worth the money, never mind the 800kms trip (and back...) to go pick them up.

Same guy also sells his Type 585 Tek scope :

https://www.leboncoin.fr/equipements_industriels/2117533952.htm

I saw that one two when I was at his place. thankfully it does look in better nick than the 575 Frankensein he sold me... but still, at 250 euros he is smoking something funny. Paid 75 or something for mine 3 years ago. OK it does not look as shiny, but I am sure it will it clean up just fine !

[Cerebus]

Machine does a much better job, much more consistent, much faster, much less sweat, and saves the little that's left of my knees

What I love about oil finishes, aside from the fact that they look good, is that they're so unfussy about application. It's impossible to do a bad job of applying them as long as for each coat you apply excess oil, wait for it to soak in, wipe off the excess and leave it to dry. Rather than making it easier to be consistent I'd have thought that a machine introduced more opportunities to get it wrong.

I don't care about the sweat aspect, one of the pleasures for me of these kind of things is that they feel like real work. That's why I don't own an electric planner, but only planes you have to actually shove yourself.

[Cerebus]

What scope maker used yellow and blue knobs?
https://www.leboncoin.fr/bricolage/2117578355.htm

Looks homebrew - note the slightly misaligned Letraset labelling.

[Neper]

Definitely homebrew and whoever made it must have been really proud and rightly so. These Mentor knobs with their collet fixing and coloured caps were used all over Europe and  are still available from the usual suspects.

[BU508A]

Echoes from a distant past

Part six - The Nordmende digital multimeter DIVO 3355 (with Nixie tubes!)

Part one - Siemens Rel. send. 22b
Part two - The Two Transformers
Part three - The Rohde & Schwarz NGU laboratory power supply unit for vacuum tubes
Part four - The Rohde & Schwarz Vacuum Tube Meter URI BN 1050
Part five - The Rohde & Schwarz UVN BN 12001 NF Millivoltmeter
Part six - The Nordmende digital multimeter DIVO 3355 (with Nixie tubes!)

Hello,
today I'd like to introduce the Nordmende DIVO 3355 digital multimeter. I think, DIVO stands for DIgital VOltmeter, but the 3355 is able to measure voltages, currents and resistance.
It is a four-digit meter with a polarity display. The AD converter is a dual-slope type and the voltage reference is a 1N825 diode. The newest date code I was able to find dates from 7508, so my instrument has been built earliest mid of 1975.
The measurement ranges are:

Voltages:
1V, 10V, 100V, 1000V with a resolution of 0.1mV, 1mV, 10mV, 100mV
Input resistance is: AC 3MOhm, DC 50MOhm

Current:
1mA, 20mA, 100mA, 1000mA, 3A with a resolution of 0.1µA, 1µA, 10µA, 100µA, 1mA

Resistance:
10kOhm, 100kOhm, 1MOhm, 10MOhm, 100MOhm with a resolution of 1Ohm, 10Ohm, 100Ohm, 1kOhm, 10kOhm

The Nixie tubes are 4x ZM1000 and one ZM1001 for the + and - sign.

The manual with all schematics and calibration instructions can be found here:
https://elektrotanya.com/nordmende_divo_3355_digitalvoltmeter_sm.pdf/download.html

But now for the pictures:


Front side with the power cord, back side, some input jacks for connecting earth buried under dust, the serial number #2570


Top and bottom view.


Mains transformer, PSU with looking-good electrolytic cap, some other electrolytic caps hiding under the transformer


1MHz crystal oscillator, some TTL logic, Nixie tubes with driver ICs


Input with fuse, some thermocoupled transistors.

And how does it perform?
I did a quick check with my DMMCheck to find out.

input shortened 0V, 5V and 1mA from the DMM check.


Resistance: 1kOhm, 10kOhm, 100kOhm

The meter is a bit off in all ranges. I think, some calibration and checking for drifted parts are on order.
Replacing the electrolytic capacitors as well. The meter contains also lots of ugly carbon resistors which needs to be checked. Ungh... 

But it is a nice bench meter with some sexy-glowing Nixie tubes. In my opinion a showpiece for every bench. 

I hope you've enjoyed this teardown.
Thank you for watching.

[Cubdriver]

Thanks for the teardown pics!  Cool old meter.   

-Pat

[factory]

@factory, did you grab that TDR? I noticed it went for a fair bit over the opening bid.



Seem to be a lot of low-end scopes on sale today, from the usual suspects.

No I didn't, unfortunately several other bidders were willing to gamble more than me. 

David

[factory]

I recently got a bunch of old (like late 70s-mid 80s) computer grade electrolytic caps, and have been re-forming them on the bench over the past week or so.  On a whim, I decided to bring up an old Honeywell DVM purchased a few years back out in CA and use it to monitor the voltage across the cap being re-formed.  It's an interesting old beast, looks to be from about 1967 based on the newest component date code I spotted at a glance, and doesn't seem to be able to store the reading - instead it counts up from zero every time it updates.  It may be supposed to store the reading (HP counters from several years earlier than 1967 could), but since I've yet to locate a manual for it I don't know for certain if that's normal or if something inside is amiss.



It's cool in that it has a VERY large display, but a bit distracting in the way it blanks for each update (blanking is an option controlled by a switch on the back, and is less distracting IMO than having the blur of the rapidly counting display with every new reading).  Following is a quickie video of the meter in operation, and a link to the gallery with further pictures of it.  I'd forgotten when making the video that I had in fact posted the pics of the insides that I took when I first got it - thought they were probably buried somewhere in a memory card, so ignore the comment about needing to take pictures of the innards.



Gallery link: https://pmanning.smugmug.com/Electronics/Honeywell-620B-DVM

-Pat

That is a strange one, the constant flashing of the display in the video is very distracting.
Some details here on the non 'B' model; https://archive.org/details/TNM_Honeywell_Model_620_Digital_Voltmeter_with_Autoject/page/n1/mode/2up
Interesting the display uses glow lamps, not seen those in seven segment form before  , guess they saved using an extra three lamps per digit.

David

[factory]

Today's TE arrival, something I've been searching for many many years to find, the hp 1784A recorder plug-in for the hp 175A scope, found it on ePay in the US, will add more pictures another day as I'm quite tired tonight.




David

[Cubdriver]

I recently got a bunch of old (like late 70s-mid 80s) computer grade electrolytic caps, and have been re-forming them on the bench over the past week or so.  On a whim, I decided to bring up an old Honeywell DVM purchased a few years back out in CA and use it to monitor the voltage across the cap being re-formed.  It's an interesting old beast, looks to be from about 1967 based on the newest component date code I spotted at a glance, and doesn't seem to be able to store the reading - instead it counts up from zero every time it updates.  It may be supposed to store the reading (HP counters from several years earlier than 1967 could), but since I've yet to locate a manual for it I don't know for certain if that's normal or if something inside is amiss.



It's cool in that it has a VERY large display, but a bit distracting in the way it blanks for each update (blanking is an option controlled by a switch on the back, and is less distracting IMO than having the blur of the rapidly counting display with every new reading).  Following is a quickie video of the meter in operation, and a link to the gallery with further pictures of it.  I'd forgotten when making the video that I had in fact posted the pics of the insides that I took when I first got it - thought they were probably buried somewhere in a memory card, so ignore the comment about needing to take pictures of the innards.



Gallery link: https://pmanning.smugmug.com/Electronics/Honeywell-620B-DVM

-Pat

That is a strange one, the constant flashing of the display in the video is very distracting.
Some details here on the non 'B' model; https://archive.org/details/TNM_Honeywell_Model_620_Digital_Voltmeter_with_Autoject/page/n1/mode/2up
Interesting the display uses glow lamps, not seen those in seven segment from before  , guess they saved using an extra three lamps per digit.

David

Interesting!  I never thought to search for a non-B model - thank you for finding that, David!  This makes me want to open it up again and dig more deeply into its construction.  More photos to follow.

-Pat

[Neomys Sapiens]

Would it be a blasphemy to convert GOS-935 to a power supply?
https://www.leboncoin.fr/equipements_industriels/2077356723.htm

I can see how you arrived at the idea, but you would be required to do the readout (numeric and/or pointer) on the CRT! 

[GreyWoolfe]

yup. Would not bid more, got too much stuff already.
- Continued with my small arcade
- had a huge bummer wrt potential buyer of the appartment called and declined
- will need to contact realtor tomorrow
- set up ultrasonic and started disassembling the Dracula pb. Which btw was called back into life by a heart transplant. (I mounted a spare CPU board)

Not feeling that great, winter blues.

That was rather funny near the end to hear the puppies trying to howl too!

Luckily, I was wearing the headphones for this. 
My dog has the genetics to be able to howl, but nobody taught her yet.  I don't plan on it either... especially not teaching a dog using youtube videos   

There is nothing so eerie hearing them live and nothing so awesome standing with 100-150 pound Grey and Artic Wolves and howling with them.  Daughter-in-law gifted Mrs. GreyWoolfe and I a VIP one on one tour at the Seacrest Wolf Preserve in Chipley Florida last month for my 65th birthday.  Temperatures were in the mid 30s F with a brisk wind and the wolves were very playful.  Truly a once in a lifetime experience scratching ears, chins and butts and having your face licked off by animals that can easily kill you.  I have many pictures but I included a few.  For reference on one of the pictures, I am 6 ft tall, his name is Dreamer and is a little over 150 pounds.
Link:  https://www.seacrestwolfpreserve.org/

[Vince]

So what's in the box then ?!

Midnight, I am just done unboxing it, taking it apart, taking pics, playing iwth it, taking note of what's good what's bad etc... and am now completely exhausted.

No way I am going to stay awake for another hour to type a report... so report tomorrow after a good night of sleep.

Wait will be worth it though, I dare to believe... some good stuff ahead...

 

[mnementh]

"Where is everybody?"   (EF)

Dwagon family has been busy making to-do & shopping lists since SWMBO decided last night that we're going to leverage the 3-day weekend to get our last load and other car from the storage unit in Ohio...

Dwagon family touched down at the homestead approx 20 min ago; road-weary but none the worse for wear. We've disconnected the trailer and emptied the cars, now raiding the fridge.

Tomorrow's agenda: away mission to the DMV/MOT/WTF-ever I have to visit to get the Saturn road-legal in Connecticut.

mnem
*goes and does some pre-queueing stretches in anticipation*

Braving the bureaucracy has been postponed; Saturn title was not in the glovebox as I thought. That means it is on one of the dozens of bins in the back of the trailer...

*insert favorite comedy unloading montage here*

Okies... trailer's unloaded, and the big bin of all my Canada workbench is downstairs in the dwagon cave. Of course, it rained all the while we unloaded, so I'm soaked to my underbelly scales and back is effing killing me.

I think I'm gonna toddle off and lie down afore I fall down...

mnem

[cyclin_al]

...just want to share the fact that people expect our corner of the world to bog down in snow completely tonight. And I'm going out for beers and lies with colleagues tonight...

Drive carefully, unless you can melt your way (flatulently)...

Thanks for the good wishes... we are still traveling through the Adirondacks, where the weather summary is: "Don't like the weather? Wait 5 minutes."

The snow, all the 10cm of it, tonight made public transport a losing proposition.  I had to walk the last 5 km home over open ground. Not very cold, not much snow, but quite windy, and the roads were mostly ice. Three buses had wedged themselves across the road, apparently, and the bus company refused to put a fourth in the mix.

I'd dressed accordingly (anorak, full set of longjohns, extra outer gloves, et c.)  and did not freeze, but the wind was quite annoying. A lesser dress would have been misery.

I long for my bench and a soldering problem.

Unlike this guy, who was not properly dressed  :
https://www.theguardian.com/sport/2022/feb/20/finland-remi-lindholm-frozen-penis-cross-country-50km-skiing-winter-olympics

The surprising part is that it is not even the first time ... 

you think a heat pack might have sped him up ?

I don't think so.  The heat generated by that much physical activity at that intensity is rather enormous.
Given that, it becomes a localized heat transfer problem.
It is not difficult to find a solution once that is understood.

The solution:
- slightly thicker synthetic (no cotton!  It holds moisture and water is great for heat transfer) underwear
- plastic bags strategically placed as close to the skin without actually touching the skin (feels icky) to make a vapour barrier to keep the clothing dry against sweat (super cold & no wind conditions)
OR
- plastic bags strategically placed as close to the outer layer of clothing as possible to block the wind chill (very windy conditions regardless of how cold)

The solutions work just as well for the ladies, except the strategic placement is different

[mansaxel]

The solution:
- slightly thicker synthetic (no cotton!  It holds moisture and water is great for heat transfer) underwear
- plastic bags strategically placed as close to the skin without actually touching the skin (feels icky) to make a vapour barrier to keep the clothing dry against sweat (super cold & no wind conditions)
OR
- plastic bags strategically placed as close to the outer layer of clothing as possible to block the wind chill (very windy conditions regardless of how cold)

The solutions work just as well for the ladies, except the strategic placement is different

I'd be inclined to test wool. A humidity-wicking synthetic close to the skin, and woolen thermal layer. Works for me, but I of course never engage in such activity levels. Being able to lift the wind-blocking layer off the skin with a bit of wool is a lot of difference.

[cyclin_al]

How can I lust after those, when I already have the wall of Lambda & Tripplite...?

the PD2005 is analog porno.

It certainly is.  That is the one that caught my attention, but I just cannot justify the PITA to import it to the GWN.
No cross-border excursions anywhere on the horizon, especially not driving that far.

[cyclin_al]

n // I am working on the bedroom. Just finished fitting the parquet, glued. Now need to oil it. Waiting for the oil to com in, then need to find a company that can rent me the machine to apply it properly.

I've never even heard of someone using a machine to oil a wood floor. Perhaps they do for massive areas, but at domestic scale? For an area that small surely it's quicker and easier to just get out a rag and get onto your hands and knees?

Cerebus' standard warning about drying oils

This is folk knowledge that tends to get passed from hand to hand but for some reason is never printed as a warning on cans of drying oils used for oiling wood.

(If you already know this please ignore, but I always post this in any discussion of drying oils becuase some people don't know this, and knowing it may save a life.)

Drying oils such as Danish Oil, Tung Oil, Linseed Oil and the like can spontaneously catch fire. Rags that have been used to apply drying oils, and that still have drying oils left on them can catch fire just from being left in the open air.

The mechanism is that the increased surface area of the oil exposed to air by being soaked into a rag causes a lot of the oil to 'dry' at once. This generates heat. The heat causes the oil to 'dry' (oxidise) faster. This makes more heat, which makes the oil dry faster - you know how this one goes, it's the classic chain reaction. The heat, combined with the insulating effect of the rag's cloth can be enough to cause the rag to catch fire.

The same applies to any material such as newspaper or paper towels used to mop up spills of drying oils or used to remove excess oil from workpieces.

When using drying oils on rags and cloths always handle the rags/cloths appropriately when you have finished with them. Either thoroughly wash out rags before disposal or storage, or soak them in water and place them inside an airtight bag or container. Do not leave rags and cloths unattended for long periods (e.g. over lunch) without taking appropriate precautions to prevent them possibly catching fire, or putting them somewhere that a possible fire will not present a hazard and will be contained.

I would also place the airtight bag or container far from the house, garage or vehicle to further reduce the risk...