Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

It's getting harder and harder to find any quality solder with clean lead and simple, organic rosin flux anymore. Well, without pay a kidney and a spleen for it, that is. 

mnem
*Current mood: 60/40*

In one of my ohmygawdtheyaretryingtochangemyworld moments I decided that good quality solder and solder wick was transforming into unobtanium and I started looking around for bargains.  At one point I bought twenty six rolls of various width NOS solder wick at a hamfest. At another, I found an electronics dealer going out of business sale and acquired five one pound rolls of multicore lead solder in various diameters and a smaller roll of silver solder. I think I have enough to last a while.

Once I bought a beat-to-hell piece of Tek gear to get the untouched roll of silver solder tacked inside. At that point, I started to think that maybe I had a problem.

Yeah, bd139 and myself did similar, we took advantage of an eBay seller who had a limited supply left and I think we had his last 20 rolls between us, so I doubt that we'll be buying any more solder, ever.

[Wolfgang]

Don’t make me post the ass of your Tek 

Edit: actually the last thing I threw together is a right piece of shit. Bob Pease style. I was experimenting to see if I can use a Widlar current mirror instead of two resistors to control a BJT multivibrator frequency yet keep consistent 3:1 duty. It worked!

I would say this is 60ies to 70ies Bronx style, a bit fluffy but you can feel the determination. 

[bd139]

the moste cute mini scopes ever are british COSSOR

Did my work experience at Cossor

Inside HM 307 not bad. Dirty so will clean out. Not esure if the choc bloc is original cable tied to the transformer. Latest date code is week 25 1980.



Only got one issue I can see:



Will ESR check the electrolytics.

Edit: just found some reference pictures and choc block is coming out 

[Specmaster]

I suspect that the choc block was to replace a dedicated voltage selection connection block mounted on the transformer, similar to the TTi psu's?

Edit: Now I've enlarged the photo, I think that the transformer has been replaced / rewound and those leads are the winding ends that would normally have been terminated at some solder tags mounted to side of the core laminations which are missing, so they improvised their own terminations. Unless the transformer gets really hot, I'd be inclined to leave the block but move it as far forwards as I could to increases clearance at the back end, and tidy up the amount of exposed contact.

[mnementh]

Okaaay... I've scoured the local swapsheets for a cheap air compressor to clean out my Ryzen7 beast once I'm all done replumbing it. Off to the bench, and will likely be quite busy for a while. 

mnem
First world problems...

[AVGresponding]

24V 2.2A (around 50VA). Issue is size and mounting.

(Attachment Link)

Sounds close to a common HVAC/Doorbell transformer. Over here they're typically 120VAC IN / 24V-28V@48-60VA OUT, and come in either "screw to the outlet" wall-wart style or encased/flanged as this one. Available at most Homeowner Hell type stores for $15-20.

I expect you'll have the same for 240VAC over there.

mnem
*wire-nut*

Nothing like that here now. All battery powered.

Heh heh I have my eye on a nice little 24V toroidal tranny in the old door hold system at the building we're refurbing. Looks to be 100-150VA or thereabouts.
It is most definitely coming home with me rather than going in a skip at the end of the job.

The run/charger tranny out of the old emergency lighting system is a different matter; I expect someone will want to weigh that one in as it's somewhere around 1.5-2kVA. Since I don't really need a transformer with around 48V @ 40A output, I'll not argue too strongly   

Speaking of big assed PSUs, this looks a bargain for anyone who can go pick it up https://www.ebay.co.uk/itm/WK-Wayne-Kerr-AUTORANGING-POWER-SUPPLY-POWERS-ON-NOT-TESTED-FURTHER-AP10090/254495700951

[Specmaster]

@bd139, OK seems I was wrong, these winding taps are supposed to go through a grommet on a partition and terminate there. That transformer is actually mounted in a hole in the partition, the likes of which I don't recall seeing before.

Edit:
Looking at the two photos, I'm beginning to think that choc block could be original but poorly terminated, the photo I found would mean that the transformer is exposed at the rear of the scope??? In my photo it looks as if the transformer was bolted to the rear panel  externally and the bottom connections have been extended but interestingly, the tappings at the top would appear that those long leads are original.

[alextwin007]

Welp now I have two more adorable scopes to keep an eye out for to add to my collection 

Since my tek 214, tek 322, nls ms-15, and waterman pocketscope need some more adorable friends

[GreyWoolfe]

Honestly what do you do with all that bandwidth?  I'm quite happy here on 63/16. I can crank that to 270/35 but I don't need it.

Ditto. I pay for 60/25 but typically get 80 down and it's more than enough.

100/10 here.  Works great here even on VPNs for work.  Typically, I get 115 or so down regardless of the time of day.  For an additional $25 a month I could go to 400 down but I can't be bothered.

[tggzzz]

Look at the page number. It's med's year of birth!

So he's actually beaten Methuselah!

[tggzzz]

cute little scopes, ok  :

the moste cute mini scopes ever are british COSSOR

Or, from https://www.eevblog.com/forum/testgear/sciaky-model-c-r-o-i-what-is-it/msg2891364/#msg2891364
there is

[Specmaster]

Look at the page number. It's med's year of birth!

So he's actually beaten Methuselah!

so what are you say here 

[Specmaster]

Here's a little idea for you folks with 3D printers should you fancy the idea.

[mnementh]

Heh heh I have my eye on a nice little 24V toroidal tranny in the old door hold system at the building we're refurbing. Looks to be 100-150VA or thereabouts. It is most definitely coming home with me rather than going in a skip at the end of the job. The run/charger tranny out of the old emergency lighting system is a different matter; I expect someone will want to weigh that one in as it's somewhere around 1.5-2kVA. Since I don't really need a transformer with around 48V @ 40A output, I'll not argue too strongly   

EVERYBODY needs JUST such a transformer!!! *coughSPOTWELDERcough*

mnem
 

[bd139]

@bd139, OK seems I was wrong, these winding taps are supposed to go through a grommet on a partition and terminate there. That transformer is actually mounted in a hole in the partition, the likes of which I don't recall seeing before.

Edit:
Looking at the two photos, I'm beginning to think that choc block could be original but poorly terminated, the photo I found would mean that the transformer is exposed at the rear of the scope??? In my photo it looks as if the transformer was bolted to the rear panel  externally and the bottom connections have been extended but interestingly, the tappings at the top would appear that those long leads are original.

That's an HM307-1 in your photo. This is an HM307-3. They made it shorter and changed the chassis for it. It does indeed look original TBH.

Found that there were 3 knackered electrolytics in it, one has leaked, so replacing them and a 1.2K 4W resistor which appears to have cracked at one end. I replaced a few other electrolytics as a "just in case" as they are quite high value. Small ones are usually ok.

[Specmaster]

Are you sure about it being shorter, looking at your photo would suggest that yours is the shorter of the two as the transformer is actually covering the first few inches of the bottom PCB which appears to be same PCB. The bottom terminals on the transformer on yours are almost directly above the connection points on the PCB and in the other photo some distance away to the left?

[bd139]

Yeah 100%. There's no provision for a transformer that sticks out on this unit. It is inside the case.

[Specmaster]

Yeah, looking at again, I can see there is a vertical board that goes across the top of the second smoothing capacitor 

[bd139]

To me it looks like it is a primitive voltage selector.

[Specmaster]

Thats what I first thought as well, rather similar to the early Thurlby psu's, they use a choc block on the transformer for the 120/240 selection.

Just went to install these new binding posts, never gave a moments thought that the mounting holes might be a different size, but the Heathkit has 9mm holes and the new posts are 7mm  , back to the search again.

[bd139]

Whoops. I think these work in them. I'm sure I used them on something heathkit a few years back: https://www.rapidonline.com/truconnect-4mm-binding-posts-83061

[mnementh]

You know you're a hopeless nerd when... You can't make yourself cut the ATX plug off a working power supply because of that little voice in the back of your head saying "Never be caught without a backup for your backup."

mnem
*Raises clawed paw* Ifni save you if you heard that in Chief O'Brien's voice.

[grizewald]

Oh well, the 34401A finally went for £191, which is probably insane for a broken meter.

Yeah that's the one I was looking at when I posted asking about unobtainium levels on display parts.

When it went past £50 I was out lol, I figured there's a fair chance the guy got it back broken because the person he sold it to swapped the good parts for bad ones and returned it DOA...

Yeah, I bailed out when it passed £75.

[WastelandTek]

so Worsthorse...did you get it?

[rcrook]

I just recently got this HP 1640A Serial Data Analyzer to try to restore. First bit of Test equipment I have bought to restore.

First thing I did was to create some replacement feet so I could at least stand it up. (I will put the STL file up on thingiverse tonight) As you can see from the photos, the CRT seems to work and I think the old 8080 CPU may still be ok, not sure about the rest though. But that's the whole point. I think it should be a cool little starting project for my upcoming addiction?


Randall.