Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Cracked it open. HT fuse blown as expected. Will check rails before I put a new one in. It is entirely unmeddled with inside. Totally pristine.

Keeper or not?

[factory]

I think I have the same variac as that, I paid just £8 for it so again laughing to the bank. Did you mean that the previous owner realigned the knob so that full rotation lined up at 100% on the scale?

No, it's got four taps (*-30-*-210-*-30-*) and the mains input is currently on the outermost two, when to get the marked 270V at maximum it should be on the first and third (with 240V mains input).

I seem to remember a Photonicinduction video where he rewires one to get 400V+ by adding a middle tap for the input. 

Thankfully, there's probably not a whole lot to go wrong in there.  And if it's HP of the vintage it looks like, it's probably fairly bullet resistant.

-Pat

Yeah, since there aren't many out there, it reduces the odds that it was in the hands of someone abusive.

The first variac I got looked perfect on the outside, only when I tried to use it (to bring something up slowly that had been stored for decades) I discovered it was completely open circuit apart from the 15A fuse (it was a 2A rated variac). 

David

[bd139]

Cracked it open. HT fuse blown as expected. Will check rails before I put a new one in. It is entirely unmeddled with inside. Totally pristine.

Keeper or not?

So far yes. See https://www.eevblog.com/forum/testgear/yet-another-465-repair-thread/

[GreyWoolfe]

Well if it passes the inspection, it must be good  What is it with cats and things in plastic bags, my 2 cats are the same, have to inspect anything in a plastic bag and they love to lick them all the time 

The resident stepdaughter has 2 cats that lick everything.  They also like to chew the cables on her wall warts.   One of my dogs likes to lick the tile floors in the house and the concrete floor in my office.  NFI why he does that.  Pets can be funny sometime, other times, not so much.

Personally I hate cats and don't want one. They're other people's problems and shall remain that way.

I agree.  I don't like them either.  I tolerate the 2 in the house.  One of her cats sheds more than both my dogs together.  Add the hairballs and cat puke and the fact that her and her husband haven't yet caught onto the fact that litterboxes need to be cleaned every day, makes things that much more pleasant.  Can't wait for them to get their life together, move out and take the cats with them.

[Specmaster]

Well if it passes the inspection, it must be good  What is it with cats and things in plastic bags, my 2 cats are the same, have to inspect anything in a plastic bag and they love to lick them all the time 

The resident stepdaughter has 2 cats that lick everything.  They also like to chew the cables on her wall warts.   One of my dogs likes to lick the tile floors in the house and the concrete floor in my office.  NFI why he does that.  Pets can be funny sometime, other times, not so much.

Personally I hate cats and don't want one. They're other people's problems and shall remain that way.

I agree.  I don't like them either.  I tolerate the 2 in the house.  One of her cats sheds more than both my dogs together.  Add the hairballs and cat puke and the fact that her and her husband haven't yet caught onto the fact that litterboxes need to be cleaned every day, makes things that much more pleasant.  Can't wait for them to get their life together, move out and take the cats with them.

In that case they can be unpleasant I agree but it's not difficult to train them to be clean or that hard to clean the cat litter tray at least daily. Cats are normally very clean animals and are fussy about there own cleanliness and appearance.

[med6753]

Well.....I'm putting my 465B final entry here because it started here. 


Final calibration and wrap up of this 465B/DM44 project. My approach to checking a scopes calibration is rather simple. Check the major functions that are most important but don't get tied up in minor stuff that for a hobbyist like me doesn't really make much difference. Besides, I'm not a cal lab nor do I have the equipment to do a traceable calibration. So I break it down to the following categories:

CRT/HV: Check the bias (which for some reason was way high), check the HV. Is the trace clean and  sharp? Is the focus OK? Yes and yes. Done.

Horizontal/Sweep: Is the trace linear? Is the sweep time accurate? Yes and the sweep time is dead on. No adjustments required. Done.

Trigger: Do the trigger circuits work? Easy to trigger? Is it stable? Yes, yes, and yes. Done. I also did a quick check of the delayed sweep and all seems good.

Vertical: Is the vertical gain accurate? DC balance adjusted properly? Here's where it needed some minor tweaks. Both channel 1 and 2 needed an equally small increase in gain. And the DC balance for the channel 2 invert circuit needed adjustment. Other than that the vertical circuits looked good.

Attenuator/Compensation: These input circuits are absolutely critical for faithful trace display and frequency response. My fear is that some twiddle happy “tech” got in there and screwed them up. Which is easy to do and a royal pain to fix. I can rest easy. No one has been in there since the scope left the factory. They are perfect. Here's 1MHz square from the Heath IG-4244 Scope Calibrator. It's excellent across all attenuator settings and both channels. No peaking or rounding. Makes me happy.



And here is 10MHz. For a 100MHz response scope this is also excellent.   


And finally, the DM44. The DCV and Ohms were calibrated a few weeks ago when this unit was on the ill fated 465. I did not calibrate nor check the Time functions as it's a don't care. And when I get a chance I'll see if I can fix the temperature probe. But other than that this 465B/DM44 is done.

[bd139]

That's looking pretty much excellent. Nice one 

[Specmaster]

Yep that's pretty much spot, what more could a hobbyist wish for?

[med6753]

I just had to throw this useless shot up here. The 3 amigos celebrating the victory over discarded test equipment. The 4th amigo (Tek 7603N) is off sleeping right now.

Total investment in these 3 scopes, including repair parts and 2 total PSU recaps, is less than $250 USD. A bargain! 

 

[Cerebus]

Is that made by General Radio? I see Zenith on it, but the style is reminiscent of meterless Gen Rad ones. They go for a pretty penny on eBay. You got a good deal on that even if it's not Gen Rad.

I don't know. In the back of my mind I remember something about a relationship between Zenith and Gen Rad, but I'm not sure. I've had it to bits this evening and the casting on the bottom of the actual transformer has "Made in England" cast into it. The winding is in beautiful nick, I'll try to remember to post some photos tomorrow when I've decent daylight to take them by.

Looking forward to see that. I'll do the same when mine gets here.

As promised; which is a rarity for me when it comes to posting teardown photos. I have a tendency to forget about photos until I've finished putting everything back together in finished form. At which point, if I remember, I tend to rationalize that it wasn't a promise, just a casual "yeah, whenever" and slink off feeling mildly guilty. Well, not this time!

I've stripped it to its major component parts as it is very clear that the cabling needs renewing - UK flexes changed from red/black to blue/brown sometime in the 70s. Getting at the turrets etc. would have been awkward in situ so I decided to just take everything apart. It also needs a little modification so that earth bonding for the case meets modern practice - the existing bonding was just screwed to the actual variac and relied on that being screwed to the case to ground the case.

Here, sans commentary, are the photos. I've got higher res if anyone wants them, these are middling size to fit forum restrictions without too much juggling - even at this moderate size I'll still have to split over two messages.

Doh! Forgot to include the original, assembled, picture:

[Cerebus]

Zenith 540A Variac photos continued:

[med6753]

Looks good!  The windings do not appear to have much wear on them. Must not have seen a lot of use.

[Cerebus]

Oh I forgot about cat shit. Nothing worse than cat shit. Apart from baby shit and that stops after a bit.

Only to be replaced by the the terrible tantrums of the two-year-old; wait but a bit longer and you get "all that teenage shit" and while it might be a different kind of shit, it's no more appealing. You're better off with cats; at least with a "long backed, retractile clawed, killing machine" you know where you are and can have a rational conversation.

[Specmaster]

Oh I forgot about cat shit. Nothing worse than cat shit. Apart from baby shit and that stops after a bit.

Only to be replaced by the the terrible tantrums of the two-year-old; wait but a bit longer and you get "all that teenage shit" and while it might be a different kind of shit, it's no more appealing. You're better off with cats; at least with a "long backed, retractile clawed, killing machine" you know where you are and can have a rational conversation.

Amen to that.

[bd139]

Got two teenagers here. Both girls. Both are fine.   

Five year old only problem is the lego caltrops.

[Cerebus]

Looks good!  The windings do not appear to have much wear on them. Must not have seen a lot of use.

Yeah, it looks like I've been very lucky. The actual variac itself seems in pristine condition. Here's a zoom in on that photo to show the track ends - the bit that gets most punishment usually. The mechanical feel when adjusting it is excellent, I've got brand-new multiturn pots with rougher actions.

[Cerebus]

Got two teenagers here. Both girls. Both are fine.   

Can I interest sir in our shotgun cartridges? We have a special line in rock salt loaded ones that are ideal for chasing off spotty teenage paramours.

[Specmaster]

Got two teenagers here. Both girls. Both are fine.   

Five year old only problem is the lego caltrops.

Young teenager girls aren't too bad, as they get older and more into boys is when the whizz banging starts so get your tin hat ready.

[bd139]

Oldest is already madly in love... 

I say that but basically she owns him.

Can I interest sir in our shotgun cartridges? We have a special line in rock salt loaded ones that are ideal for chasing off spotty teenage paramours.

I am interested in those for the Jehovas Witnesses 

[Specmaster]

Oldest is already madly in love... 

I say that but basically she owns him.

Can I interest sir in our shotgun cartridges? We have a special line in rock salt loaded ones that are ideal for chasing off spotty teenage paramours.

I am interested in those for the Jehovas Witnesses 

Never thought of that application but makes sense does that. [emoji48]

[med6753]

Oldest is already madly in love... 

I say that but basically she owns him.

Can I interest sir in our shotgun cartridges? We have a special line in rock salt loaded ones that are ideal for chasing off spotty teenage paramours.

I am interested in those for the Jehovas Witnesses 

Never thought of that application but makes sense does that. [emoji48]

Oh, you get them over there too? They are a strange bunch. 

[bd139]

I live right near Twickenham Stadium where they have their annual convention unfortunately. It's like swarms of the bastards. 55,000 of them usually.

Knock knock. Have you heard the good news? Oh you heard about my haemorrhoid surgery then?  Total silence. 

[mnementh]

Reminds me of this which I saw the other day:



Edit: my father's cat was hilarious. I chewed through a mains cable and hit live. There was a thud as it hit the underneath of the table, shot off and ran straight into the glass door on the back of the house. Never chewed anything ever again after that.

*SNERK!!!* Static Klingon Kitteh!!!

In Other News...

My fuses & precision resistors from n2cbu have arrived; Fuses test to spec for resistance as advertised and now the ones I snurched from my Ragu 17B are back where they belong.

It took some jiggery-pokery to get good contact through the baggies, but 100ohm 0.1% resistors read 100.09/100.11ohm, and the 5.315K 0.1% I could get contact with read 5316ohms with the 189. I think that's pretty good. Still awaiting the rest of my parts to make the cheap resistance array, and I'm loathe to take them out of the baggies until I'm ready to build.

mnem
ZZZzzzZZZzzzombie...

I got some things from him too, most for no real good reason other than the prices were good and I'll keep them in my spares stock.  The adapters and attenuators will go in my RF goodies box, and I want to try the DC-DC converters for driving nixies.

    Incoming QA inspected things and approved, too, so it's decent stuff...   
-Pat
<edit - I got some things, not somethings.  Damned space bar!>

Yeah, he has oodles of stuff that I'd normally buy on speculation for the "stuff-n-such" drawers... but right now, those drawers are at the top of the list of stuff being decimated for the move. Fortunately, (Unfortunately?) now I've got him in my watch list, so I'll be able to find him as soon as such stuff becomes "a thing" for me again. 

The moment I start carrying a new shipment inside our cat is looking for which box to claim as her own.   
Get a new unit out to do my pre-dispatch checks and I'm swatting her off the empty box.

One day she'll get shipped to some unsuspecting customer. 

Well if it passes the inspection, it must be good  What is it with cats and things in plastic bags, my 2 cats are the same, have to inspect anything in a plastic bag and they love to lick them all the time 

  Lick.   

I wish all the little buggers did was lick!
        Piglet and Gilmore seem most inclined to this.

And of course they ingest some of it, then barf it up later - normally while I'm asleep, and typically somewhere on the path between the bed and the bathroom - that increases the likelihood that I'll step on it with my bare feet while half asleep in the dark.  I think this amuses them greatly. 

-Pat

If there's one thing I don't miss about having cats since I married an allergic opera singer and DON'T... it's being woke up from a sound sleep by a cat stepping on your tongue as they chase each other around the room. If you live with cats long enough, it WILL happen. *kakkk*

Personally I hate cats and don't want one. They're other people's problems and shall remain that way.

Dirty, needy, murder all the wildlife, toxoplasma gondii, get hair over everything, expensive vet fees, horrible smelling food, twisted violent, unpredictable and generally useless as a service animal as well. We had a cat years ago we got to catch mice and it was useless. It'd just lick them a bit. This resulted in me having to regularly chase a damp mouse around the living room taking pot shots at it with a metal ruler. Had to get rid of it in the end as it went for my daughter. Just few across the room at her and dug claws in. She was only 8 months old then. 

No pets rule in this house. Can go to the local urban farm if they want to do that stuff. And wash their hands afterwards!

Edit: plus my father's one used to come and sit on my face when I was asleep. Total wanker that cat.

I've always preferred cats for one reason; if you treat them poorly they'll leave, so their affection (when given) is genuine, rather than a byproduct of the typical Stockholm Syndrome relationship most dogs have with their person.

While everything you say about them is technically true, I have to wonder    if your father's cat wasn't EXACTLY the cat you deserved.     

I just had to throw this useless shot up here. The 3 amigos celebrating the victory over discarded test equipment. The 4th amigo (Tek 7603N) is off sleeping right now.

Total investment in these 3 scopes, including repair parts and 2 total PSU recaps, is less than $250 USD. A bargain! 

And my 465 army continues to grow!!! Muahahaha!!! 

Seriously though... good score; I really am envious of the DMS. Great to see that much Tek pulchritude all in one place; makes me want to crack open the NASA 2465. Again.   

Got two teenagers here. Both girls. Both are fine.   

Five year old only problem is the lego caltrops.

Young teenager girls aren't too bad, as they get older and more into boys is when the whizz banging starts so get your tin hat ready.

mnem

[med6753]

I live right near Twickenham Stadium where they have their annual convention unfortunately. It's like swarms of the bastards. 55,000 of them usually.

Knock knock. Have you heard the good news? Oh you heard about my haemorrhoid surgery then?  Total silence. 

And they have no respect for private property either. Access to our apartments is via a locked front door. One of the upstairs tenants had a habit of putting a shim in the door so it would remain cracked open because they didn't "feel like" carrying their key. I woke up one afternoon to find their flyer under my door and the front door open. I was pissed. If I had caught them at the very least thrown them out and perhaps called the cops. And I also took care of the lazy ass upstairs who didn't want to carry their key. That door is locked at all times now.   

[mnementh]

As promised; which is a rarity for me when it comes to posting teardown photos. I have a tendency to forget about photos until I've finished putting everything back together in finished form. At which point, if I remember, I tend to rationalize that it wasn't a promise, just a casual "yeah, whenever" and slink off feeling mildly guilty. Well, not this time!

I've stripped it to its major component parts as it is very clear that the cabling needs renewing - UK flexes changed from red/black to blue/brown sometime in the 70s. Getting at the turrets etc. would have been awkward in situ so I decided to just take everything apart. It also needs a little modification so that earth bonding for the case meets modern practice - the existing bonding was just screwed to the actual variac and relied on that being screwed to the case to ground the case.

Here, sans commentary, are the photos. I've got higher res if anyone wants them, these are middling size to fit forum restrictions without too much juggling - even at this moderate size I'll still have to split over two messages.

Doh! Forgot to include the original, assembled, picture:   

Fine, fine... you twisted my arm. 

   

Here's my own Step-Up/Step down gear. These were just unearthed a few days ago... I was actually about to stuff both of them in one of my keeper bins. On the left is a medical power control module as was commonly used to control the brightness of operating room swingarm spotlighting. This is actually the second one of these that I acquired at a medical surplus auction along with ~100kg of oxygen regulators and a fabulous freestanding LUXMAN magnifying light which used to be by my workbench. The other module was set up full-time as part of my workbench. My guess is '70s vintage for the modules and the TRAMAG 2:1 step-down. I eventually will mount them together with the step-down as an add-on in cases where I need finer granularity or so I can reverse it and use as a 300va isolation transformer.

Inside the power module is a General Radio W5 series Variac with a double-pole circuit breaker rated at 7A; my guess is the large enclosure was to keep the full 6A rating of this family of Variac. The shaft is double-insulated so they can use that delicious machined aluminum knob; when I renovate this one I'll make a replacement for the missing phenolic disc that should be there on top of the shaft.

Once we've moved, this and a number of other similar projects will be back on deck. 

Here's a link to a .pdf of a tech newsletter from when GenRad first released the W5 series; interesting stuff.  IET Labs still hosts a huge archive of GenRad literature of both historical and technical interest.


mnem
I have tha powaahh!