Test Equipment Anonymous (TEA) group therapy thread

[bitseeker]

Well, that grew quickly, didn't it? I suppose you can look at Pat's lab repair queue as one potential future of yours. But first, your HP collection needs to outnumber your teeth.

Fixed it for you.   Come on, let's try to be precise here, we're technical types!!   

Most of it is still in the 'to be wrung out' pile!  (And yet I keep buying more!    )

Thanks, Pat. Always good to have extra eyes on my posts.

[beanflying]

Finally got around to cracking the lid on my Quadtech 1880 milliohm meter. NOT a Quadtech which I suspected but made by Chen Hwa in Taiwan. REF02 voltage reference btw.

Wondet if the clunky bodge was factory

[Brumby]

Of course, Avro's have form. Eric Brown rolled a Lancaster on 16th May 1947.

Please stop talking about aircraft! I loved them years before even knowing the word 'electronics'. Now I envy you for that as well!

You really know how to torture me. 

I prefer the Handley Page Victor over the Vulcan, though. That was was a real beautiful ugly bird (and Handley Page, HP, fits quite well in here.  )

I served my military duty in the air force, but didn't even get close to any aircraft, which was extremely disappointing. 

What, you want mercy.. after you tortured us all with your massive dumpster hauls, its you who knows how to torture us other poor long suffering TEA lovers with your fantastic hauls 

Your right, that Victor was a real ugly bird, but still a highly capable one, but it was the Vulcan that captured everyone's imagination though.

How can you serve in the Airforce but not get close to aircraft?

Like a cousin I have - they worked in accounting for the RAAF.  Interestingly, they still get rank such as "squadron leader".

That would kill me ... being so close to aircraft and not going up.  Doesn't have to be as part of the flight crew (although that would be nice).  I did some (commercial) air travel in the nineties and always asked if I could ride the jump seat in the cockpit.  Scored a few landings into Sydney and Melbourne, but never a take-off.  That all changed in 2001   

[GerryBags]

Another day in which I willingly gave myself a cashectomy, although I'm not sure it's helping to cure my test-kititis - just giving me elephantitis of the workbench. It's a little bit like trying to cure morphine addiction with heroin..... or fake Chinese methodone.

[neo]

Can a 2n2219 be used top temporarily replace a 2n3300?

http://www.ttelectronics.com/themes/ttelectronics/datasheets/semiconductors/transistors/SF_2N3300.pdf
http://www.onsemi.com/pub/Collateral/2N2219-D.PDF

One of my favorite multimeters just let the magic smoke out.

[bitseeker]

elephantitis of the workbench

Hopefully, you have a very sturdy workbench.

[GerryBags]

Hopefully, you have a very sturdy workbench.

Sturdy-ish..... why waste money on a good strong bench when I can spend it on vital, if bulky and occasionally broken, test gear? If you keep stacking it up long enough, I'm thinking it will eventually compress and form some kind of copper rich aggregate which might act as a support for the later strata of gear? Like sea-shells. 

[Ero-Shan]

What, you want mercy.. after you tortured us all with your massive dumpster hauls, its you who knows how to torture us other poor long suffering TEA lovers with your fantastic hauls 

Massive, granted. But most of the stuff not really awe inspiring. Compared to the Nixie wall, e. g., it looks terribly boring. 

At work, the yearly calibration of our TE was due. During the warming up, a HP34401A, a Fluke 8050A, a Fluke 45 and a Knick JS3010 behaved badly. And there already was a planned visit to the electronics graveyard! Guess what happened ... 

How can you serve in the Airforce but not get close to aircraft?

They ran their own microwave communications network back in those days, and I was at one of these stations. The barracks we were had an airfield, but that didn't see much use after WW2. Most of the time there was absolutely nothing to do. During one of the shifts I brought the mainboard of my newly acquired (though second hand) PET 2001 and reverse engineered it. When I finally had the schematics, the modifications started ... 

[bd139]

Well the HP 54602 didn’t die in vain. I’ve managed to nick enough parts out of it this morning and adding a single AD8307 from China, to build a log power sensor. Just doing the board now. SMD board with etch resist pen is “interesting” as my printer is dead. 

[neo]

Can a 2n2219 be used top temporarily replace a 2n3000?

http://www.ttelectronics.com/themes/ttelectronics/datasheets/semiconductors/transistors/SF_2N3300.pdf
http://www.onsemi.com/pub/Collateral/2N2219-D.PDF

One of my favorite multimeters just let the magic smoke out.

Unfortunately it is a bit more involved than that, i'm going to need someone who can make sense of this power supply schematic to help me.

http://bama.edebris.com/manuals/systrondonner/7050


I'm strongly tempted to just put a 317 in here for the 3.8V....

[bd139]

2n3000 is PNP. 2n2219 is NPN. 

I'd have a look but I can't open either of the PDFs in that BAMA page with Adobe reader.  317 would probably do the job though. It's a more modern solution for sure.

Edit: complementary PNP of the 2n2219 is 2n2905. That would work but fT is very high so it might break into oscillation. If it does that, stick a 47pF ceramic cap across base-emitter on the transistor. This will increase miller capacitance which will slow the transistor down considerably.

[ChrisLX200]

I checked Amazon again and these DPS5015 units are still being listed at £3.99 - 9 in stock (well, there were until I bought 5 of them, now there's only 4 )

https://www.amazon.co.uk/gp/product/B07433NF8F/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1.

[neo]

2n3000 is PNP. 2n2219 is NPN. 

I'd have a look but I can't open either of the PDFs in that BAMA page with Adobe reader.  317 would probably do the job though. It's a more modern solution for sure.

Edit: complementary PNP of the 2n2219 is 2n2905. That would work but fT is very high so it might break into oscillation. If it does that, stick a 47pF ceramic cap across base-emitter on the transistor. This will increase miller capacitance which will slow the transistor down considerably.

Apologies i meant to type 2N3300, i put the right datasheet though. Growing tired of chasing my ass i put the 2n2219 in there and it sprang to life,thus answering my question...

Proper transistor on order, mysteries as to what is wrong with the first one still unanswered, and meter is fixed... for now. This thing has a tendency to break in new and interesting ways. 


Edit to add:

Sometimes when repairing stuff it does seem to be OK to just follow your gut and roll with it.

[plazma]

I checked Amazon again and these DPS5015 units are still being listed at £3.99 - 9 in stock (well, there were until I bought 5 of them, now there's only 4 )

https://www.amazon.co.uk/gp/product/B07433NF8F/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1.

I ordered the last.

[bd139]

2n3000 is PNP. 2n2219 is NPN. 

I'd have a look but I can't open either of the PDFs in that BAMA page with Adobe reader.  317 would probably do the job though. It's a more modern solution for sure.

Edit: complementary PNP of the 2n2219 is 2n2905. That would work but fT is very high so it might break into oscillation. If it does that, stick a 47pF ceramic cap across base-emitter on the transistor. This will increase miller capacitance which will slow the transistor down considerably.

Apologies i meant to type 2N3300, i put the right datasheet though. Growing tired of chasing my ass i put the 2n2219 in there and it sprang to life,thus answering my question...

Proper transistor on order, mysteries as to what is wrong with the first one still unanswered, and meter is fixed... for now. This thing has a tendency to break in new and interesting ways. 


Edit to add:

Sometimes when repairing stuff it does seem to be OK to just follow your gut and roll with it.

Following gut feeling works most of the time.

Some of the older transistors tend to lose beta pretty heavily. This causes them to increase voltage drop across Vce and dissipate more power. Eventually they snuff it via release of smoke. Fluke in particular - had same with my 8000a.

2n3300 makes more sense

[Specmaster]

Good evening. Was at parents all day and they have shitty reception.

Bought a new function generator to replace the DG1022Z. TTi TG215. Basic 2Mhz analogue unit with digital frequency readout. I had a TG210 a while ago which I sold when I bought the DG1022Z. That was a silly idea as I found the DG1022Z was a noisy buggy fucker so this will free up some cash to grab a Marconi 2022/2019 if one turns up. This removes the last whining Chinese fan piece of crap from the bench.

You got me thinking now, is it possible to have a fully functioning lab/workshop kitted out with nothing other then British designed and built test gear, at reasonable cost?

[bd139]

That is entirely possible. I can’t say I haven’t thought of it before. Mainly because the designs are usually top notch and made of bog standard parts with pro electron numbering which are really easy to get here. Also when you get a “bad tek or HP day” ie having to pull the interface board out of a 475 or nearly kill your self trimming a power supply, you just want that engineering to go away

TTi function generator, counter, power supplies, DMMs. Gould/Telequipment scope. Marconi RF gen and spectrum analyser. Antex iron (one of their higher end ones not fire stick).

If you want to jump into Europe a bit, it’s possible to kit a bench out with just Philips kit. That’s really nice. If you pit a PM3055 against a Tek 2225, which has the same price tier around the 1990 mark, the tek is shit

I prefer a BC549 to a 2N3904 as well

Edit: hmm I’m liking that idea.

[ChrisLX200]

I checked Amazon again and these DPS5015 units are still being listed at £3.99 - 9 in stock (well, there were until I bought 5 of them, now there's only 4 )

https://www.amazon.co.uk/gp/product/B07433NF8F/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1.

I ordered the last.

 


I don't pretend to know what's going on here, but if you search the entire Amazon site using the keywords  DROK  or DEOK  you get listed dozens of items priced mostly at £3.99. This can't be right, while some might be genuine sale items others (it seems to me) are vastly under-priced compared to similar products on there. Anyway, I stocked up on a few bargains   I suspect a general screw-up with the pricing structure - unless Amazon really, really, want to clear their shelves of anything sold under those names...

[Specmaster]

Its one that I've been nursing for a while now since I started with the TTi counters and added the pulse generator, your further into this then I am now because you have the counter, function generator and the power supplies from TTi already. Their 1604 meter looks tasty.

Problem is of course as you rightly said, the designs are normally top notch and they also carry the price tag to match, I'm thinking I should have embarked on thiis quest a few years agoi while I was working to pay for it all

Never know, might get lucky and come across the gear at reasonable affordable prices like we did with the counters 

[bd139]

Some of it goes for not much money. I have not paid more than £30 for my power supplies so far for example. Think I paid £30 for my TG210 before.

Another manufacturer to look out for is Farnell. Their power supplies are nice.

[Specmaster]

I looked at Farnell power supplies earlier and came to the conclusion that many were badged and sourced from overseas. Others I've seen have expensive, you do well to get them for under £30 pop.

[bd139]

They were all made in the UK. The E30/2 I was using here was a fine example of one of their supplies (and the TG210, and a British Black Star counter ):



Inside they're pretty good. Fully discrete transistor design, high quality Sprague electrolytic filter caps, Motorola branded transistors.

Note: they missed a couple of things that people sussed in later power supply designs. Particularly reverse voltage protection diodes. You can add a 1N5403 across the output and the pass transistors. Then they don't blow up when you use them in a load that can supply current (big capacitors/battery charger etc).

That picture shows how variable my kit collection is. The only thing I still own there is the Fluke handheld and the breadboard and leads.

Edit: also worth looking at the old Thandar line:

http://azurelectronics.com/Thandar%20Stack.htm

[Specmaster]

Should've kept that 1740A I reckon.

I had one of these counters as well, but the 100 model, worked really well as but much rather have the TF930 though. I bet if you stick that Fluke on a voltage reference it would still be spot on as well.

I have got 14 Flukes, many had cal stickers on them that expired way back in 2010 and they are all well within the spec, very imprressive.

[bd139]

The 1740 wasn't going to be a keeper. I don't like the flood gun illumination on them. Tek got that a bit better.

Found a picture of the guts of the Farnell E30. The whole thing breaks in two if you pull it. So you've got the high voltage and filter sections on the rear as well as the pass transistor and the front is the regulator and low voltage stuff. Quite neat for working on it.



That Fluke was knackered when I got it. Took me a few days to get it working properly again. It was used in a kitchen as a thermometer so was chock full of shit, most of which had migrated to the high impedance parts and knocked it all off. Also the display had gone.

[Specmaster]

I checked Amazon again and these DPS5015 units are still being listed at £3.99 - 9 in stock (well, there were until I bought 5 of them, now there's only 4 )

https://www.amazon.co.uk/gp/product/B07433NF8F/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1.

Thanks for the heads up, just made a purchase, nothing overboard though,

https://www.amazon.co.uk/gp/product/B072MCXR7W/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B01N5MPKH1/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

and these at the same time.

https://www.amazon.co.uk/gp/product/B01MRAEY6M/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B071D7LJ31/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1