Test Equipment Anonymous (TEA) group therapy thread

[URI]

@URI, I don’t know which model of T12 power supply you’ve looked at but on mine solder mask is not being used as the means of isolation. The psi sits in 2 channels on the side walls close to the bottom, there is a gap of around 6mm between the trace side of psi and metal case and in this gap there a piece plastic insulation. Granted there are 2 tracks that actual go into channels, and run the length of the pub. I was concerned about this myself as the case was not earthed so I investigated further and found that those 2 tracks in the channels were in carrying the earth connection from the rear terminals to the front to earth the socket and iron tip. Therefore I concluded that the only modification needed was to bond all the metal case parts to each other and the main incoming earth connection.

I've ordered the KSGER T12 controller.
The KSGER 24V switch mode power supply you can also order it with has a serious design flaw, check this:
https://www.youtube.com/watch?v=QESGY5LzPPw&feature=youtu.be&t=154

I have had mine now for 2 years and have never had any trouble with them at all and I have worked on many sensitive parts with the iron connected to the house ground and have not destroyed anything yet.

EDIT.
I just read your reply above, there is no point in providing a earthed lead to the tip that you can then connect to your ESD mat or to house ground since that require a return path to the leakage voltage source that your trying to eliminate. There will not be a path for this leakage to dissipate to 

With your tip grounded to earth you are just lucky to not having destroyed any ESD-sensitive parts. An earthed tip doesn't limit currents of ESD discharge.

I think I was not clear enough describing the connector to the tip:
I will add a 4mm plug socket that is connected to the tip. The tip is freely floating.
With this I can then connect the tip to whatever is appropriate for the solder job to be done.
- tip left free: freely floating, not ESD compliant
- tip connected to ESD-hub (1MOhm in series through ESD-hub-connection), ESD compliant
- ...

[URI]

Believe me, there has been serious thoughts on my side building the power supply that way.

1. Isolation:
My first approach was to just take an off shelf switch mode power supply. That would have provided an isolation one could be sure of not to be killed by it someday.
BUT:
These switchers do have capacitive voltages to ground, the output isn't floating as freely as one would assume; A CMOS circuit could be offended by that and decide to go dying...   

Second approach: Isolation using a transformer. Choosing a transformer that is certified for SELV/PELV circuits on the secondary side would give me the isolation safely that I need without switch mode residual voltages to ground.
In fact, the older Weller station with two wire input, fully isolated case and a transformer do exactly that.

Conclusion: Building a fully isolated power supply with two wire mains connection built in an fully isolated case.
This is a concept of double isolation (like the Weller stations I mentioned above) and protects the user from touching any mains parts or parts that could carry mains if a failure occurs.
[..]

You don't have to put a SELV transformer in a plastic enclosure. put it in a metal box and connect that to ground but keep the secondary isolated. If you want to keep the iron tip seperate from the mains earth just bring it out via a series resistor to a 4mm socket for connection to the ESD station ground. The is no reason not to connect it to mains earth via a high resistance.

If you really want isolation but a 24V batter and charger in a box with the battery powering the soldering station and connected to the mains charger by a two pole relay. Relay coil connected to a switch on the iron holder so when you lift the iron only the batery is connected.  Also gives you a portable option.

Switch on the holder reminds me of the old trick of putting a diode in series with a non TC iron when in the holder so it does not over heat when sitting idle.

I know that I don't have to put a SELV/PELV Transformer into a plastic case.
On the other hand I don't want earth anywhere near the soldering Iron circuit.
That's why I chose double isolation with a plastic case: I only feed phase and neutral into that. No need to earth anything then.

[factory]

6294a arrived. Looks good so far.

Firstly I got the shit scared out of me. It arrived in a wet cornered box wrapped in plastic. The wet turned out to be diesel or something similarly nasty based on the smell. Has been disposed of outside as has all packaging.

I've cleaned up poo, & I've cleaned up diesel---------I prefer poo!

Fortunately the power supply was perfectly fine inside it  . And it's in reasonable condition


Need to get rid of this horrid thing off it first


Insides. Date coded around 1989 so this is a VERY late example. This product line ran from 1968 to 1990 approximately which is a hell of a long time.

Tidy up and test later.

Edit: oh win, just seen the voltage pot is a 10 turn one.

Pretty!
I want one! I want one! Wahh! gimme!

I don't have TE syndrome,-------------how could you think that I do?

It'll probably be available in a few months when BD has bought something else, problem might be the cost to send it other.

David

[factory]

The HP 6255A delivered by TNT arrived intact. 


As I had bought a cheap step-down transformer when Maplin closed in Crewe, I decided to do a brute force test & reformation of the capacitors.
One half is of the supply is dead and the other side is working fine, voltage controls are 10-turn as well.

A quick check of the fuses revealed they were fine, looking closely the power switch isn't switching both live & neutral but the two lives to the transformers, doing a "Shango066" & shoving an insulated screwdriver across the contacts confirmed the switch is half knackered and the other side of the supply was working fine too. 



Job for Friday afternoon, spend 10 minutes fitting a new switch and 3 hours locating the switch. 

David

Nice. Glad yours turned out a winner 

Quick update on the HP 6255A dual PSU, I've located a choice of two different replacement toggle switches from the stuff I bought & cleared from work.

Now the expensive parts with mine will probably be getting some knobs to replace those locknuts. The voltage & current controls are both 10-turn, so apparently the knobs would have been the type with no pointer (as shown below), I may have to use whatever I can find/buy.


I can't help thinking BD had a single version of this HP power supply last year, it's the type with the large power resistors at the back.

David

[bd139]

Mine was the Harrison 6284A. Close but not quite. Anything that kicks out more than 30W has a “bar fire” on its butt. This is used to divert a chunk of the current past the pass transistor so you don’t need to sink it.

I noticed on my new baby that the thing is 3x 75W wire wounds! These days it’d be a shit MOSFET, a fan and some praying.

[GreyWoolfe]

I will not make it to discord this evening. Today, some friends and me have cleared the house of our friend Obri which died in May this year because of a cerebral haemorrhage. He was clearly suffering from TEA and it took ages to go through all this stuff. *uff*

When I went home, I got for my collection

- a Keithley 2100
- a Fluke 8845A
- and some scope tubes of various sizes. Must check them tomorrow.

Pictures will follow.
Now I'm dead for the rest of the day and a huge part of the Sunday.
Sometimes, I wish I would be 20yo again...

Yes, I also and I suspect most of us older generation folks on here also would like to be 20 again, I know for certain that I'd love to be that age again right now. Sad to hear about your friend, but at the very least you have something to enjoy that was his and to always remind you of him, enjoy your weekend.

Good God, YES!!  I spent 5 hours on Friday crawling under desks unboxing equipment and routing power cords and cables helping a fellow tech move a customer's site.  Back was properly cranked up after a 2.5 hour drive back home in my sh!tty Nissan NV200 company van. 1 Flexeril and 3 Tylenol that night from Mrs GreyWoolfe wasn't near as much help as I had hoped.  Thankfully all the time spent on site yesterday was moving from station to station configuring the new toys to work so that was easier on my back.  Still a 13 hour day with almost 5 of that traveling in above said van including rain the entire drive home.  Ended up with 21 hours of OT for the week, Mrs GreyWoolfe very happy, my old carcass, not so much.

Sorry for your loss.  I was in almost the same position a couple of years ago.  A fellow co worker became a dear friend over the years and had passed away from a heart attack while in the van on his way to a service call.  His widow and son blessed me by giving me his tools including a Jensen field service tool kit that I cherish and use regularly. 

[bd139]

So, anyone bidding on this?

https://www.ebay.co.uk/itm/254738813715

[med6753]

So, anyone bidding on this?

https://www.ebay.co.uk/itm/254738813715

Are you nuts? 

[bd139]

Hey don’t knock it. They are nicely aged parts if you look closely. People would pay serious money for an LM399 aged that well.

[jonovid]

The HP 6255A delivered by TNT arrived intact. 


As I had bought a cheap step-down transformer when Maplin closed in Crewe, I decided to do a brute force test & reformation of the capacitors.
One half is of the supply is dead and the other side is working fine, voltage controls are 10-turn as well.

A quick check of the fuses revealed they were fine, looking closely the power switch isn't switching both live & neutral but the two lives to the transformers, doing a "Shango066" & shoving an insulated screwdriver across the contacts confirmed the switch is half knackered and the other side of the supply was working fine too. 



Job for Friday afternoon, spend 10 minutes fitting a new switch and 3 hours locating the switch. 

David

Nice. Glad yours turned out a winner 

Quick update on the HP 6255A dual PSU, I've located a choice of two different replacement toggle switches from the stuff I bought & cleared from work.

Now the expensive parts with mine will probably be getting some knobs to replace those locknuts. The voltage & current controls are both 10-turn, so apparently the knobs would have been the type with no pointer (as shown below), I may have to use whatever I can find/buy.


I can't help thinking BD had a single version of this HP power supply last year, it's the type with the large power resistors at the back.

David

there is something really satisfying about the look & feel of rack-mounted electronic equipment. 
similar could be said of aviation /military grade knobs and switches.

[factory]

So, anyone bidding on this?

https://www.ebay.co.uk/itm/254738813715

Are you nuts? 

Description states they were bought for an art project, maybe they need to change that & the category as it's not too far from Bonfire night. 

David

[factory]

Mine was the Harrison 6284A. Close but not quite. Anything that kicks out more than 30W has a “bar fire” on its butt. This is used to divert a chunk of the current past the pass transistor so you don’t need to sink it.

I noticed on my new baby that the thing is 3x 75W wire wounds! These days it’d be a shit MOSFET, a fan and some praying.

That is from the same series of PSU's, just different output voltage/current (same power rating).
Manual has some shared diagrams hence the original question.

We had it's bigger & heavier brother at work, a HP 6274B 60V 15A (only 48lbs), but that uses an triac based pre-regulator.
You would hate it as it has a cooling fan.

David

[Cerebus]

Hey don’t knock it. They are nicely aged parts if you look closely. People would pay serious money for an LM399 aged that well.

Agreed, but considering the particular parts involved I don't think "aged", in the sense of nicely matured, is exactly apposite. I think I'd be opting for another short word beginning in 'a': armed.

[0culus]

Hey don’t knock it. They are nicely aged parts if you look closely. People would pay serious money for an LM399 aged that well.

 

[capt bullshot]

So, anyone bidding on this?

https://www.ebay.co.uk/itm/254738813715

Oh nice, firecrackers!

[mansaxel]

I did succumb, and hand-sniped a tolerable bid with 2 seconds to go, so am now awaiting a MetraHit 25S.



Picture from ad. Report when I've got it here.

[Specmaster]

So, anyone bidding on this?

https://www.ebay.co.uk/itm/254738813715

Been sniffing glue again? They look bloody dodgy to me, so no. Are you then

[capt bullshot]

The K238 from Ice-Tea now finally found its destination:

[Saskia]

@mansaxel congrats.

working on tax declaration. for those of you who know German tax declarations, you know what I am going through.
For those who don't:  it's a thick A4 binder full of stuff that I have to submit.
Probably 100 - 200 pages all in all ...

[Specmaster]

Ok, all parts for the TTi PL310 power supply are now ordered, report and photos to follow once they arrive, photos will be stage-managed as I have already stripped it down but my bench was not really suitable for photos, so I take some when I rebuild it. A reverse tear down, there's a novelty for you. 

[URI]

The K238 from Ice-Tea now finally found its destination:

I enjoy exploring photographs of your bench/TE stack!   

[URI]

working on tax declaration. for those of you who know German tax declarations, you know what I am going through.
For those who don't:  it's a thick A4 binder full of stuff that I have to submit.
Probably 100 - 200 pages all in all ...

I'm sorry for you,  tax declaration is something I always hated. Have given that to someone who earns money with it. It's still a plus for me because I win the sour time otherwise wasted with filling out forms, get invoices, documents, receipts, etc together.

But 100 to 200 pages!   

Your revenue officer must hate working through your tax declaration.    

[0culus]

My project for the "Tag der Deutschen Einheit":

Add some reasonable power distribution to the lab cart:

I really like that cart. Looks sturdy. Where'd you get it?

[capt bullshot]

Just for the giggles.

A multicolor (green has been borked by some philistine) LED:



Running at 0.1mA



and 1A



Of course, the current was precisely set by that K238.

[capt bullshot]

My project for the "Tag der Deutschen Einheit":

Add some reasonable power distribution to the lab cart:

I really like that cart. Looks sturdy. Where'd you get it?

The metal frame with the attached wheels came from scrap @work (AFAIR, these carts were build in-house back then), I replaced the rotten boards with new beech wood boards.