Test Equipment Anonymous (TEA) group therapy thread

[BU508A]

And, no, I am not going to buy a tube tester.   

If not buying a tube tester, but how about building one? 

http://www.roehrentest.de/

[med6753]

And, no, I am not going to buy a tube tester.   

If not buying a tube tester, but how about building one? 

http://www.roehrentest.de/

I've seen those videos on the latest type software controlled tube testers and actually thought about it until I saw the price. Are you nucking futs? 

The only way I could ever justify getting one is if I did extensive audio work and I needed to match tubes (Often!  ) That's where those testers excel. 

[VK5RC]

When I repaired my Tek 545, I built the uTracer tube tester from https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
You need a PC to connect it to but it then graphs the tubes, the source/sink unit is relatively easy to build but getting all the different tube sockets and wiring them, with ferrites was challenging! Overall I am very happy with it - seems more useful than typical testers.
I also agree tubes are generally quite reliable - much more so than electrolytic capacitors. My tek had a shorted electrolytic and a buggered rectifier tube.  I think there was one other dead tube out of multiple tens of tubes!

[Specmaster]

Is there anybody in here, it seems to be pretty dead to me 

[med6753]

When I repaired my Tek 545, I built the uTracer from https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
You need a PC to connect it to but it then graphs the tubes, the source/sink unit is relatively easy to build but getting all the different tube sockets and wiring them, with ferrites was challenging!
I also agree tubes are generally quite reliable - much more so than electrolytic capacitors. My tek had a shorted electrolytic and a buggered rectifier tube.  I think there was one other dead tube out of multiple tens of tubes!

If you look through old Tek manuals they state quite clearly not to routinely pull tubes for testing. They state that the best test for proper operation is simple substitution. 

[med6753]

Is there anybody in here, it seems to be pretty dead to me 

I guess I'm nobody. 

[BU508A]

And, no, I am not going to buy a tube tester.   

If not buying a tube tester, but how about building one? 

http://www.roehrentest.de/

I've seen those videos on the latest type software controlled tube testers and actually thought about it until I saw the price. Are you nucking futs? 

The only way I could ever justify getting one is if I did extensive audio work and I needed to match tubes (Often!  ) That's where those testers excel.

The hardware is one thing, but there is also this (increasing) huge database behind it which contains the data of a lot of tubes, even  exotic ones. I think, this is one of the biggest advantages of this roetest tube tester. A lot of people do still contribute to this database.

But you are right. For a hobbyist this might be an overkill. But hey, we are here in the TEA forum, aren't we?     

[BU508A]

When I repaired my Tek 545, I built the uTracer tube tester from https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
You need a PC to connect it to but it then graphs the tubes, the source/sink unit is relatively easy to build but getting all the different tube sockets and wiring them, with ferrites was challenging! Overall I am very happy with it - seems more useful than typical testers.
I also agree tubes are generally quite reliable - much more so than electrolytic capacitors. My tek had a shorted electrolytic and a buggered rectifier tube.  I think there was one other dead tube out of multiple tens of tubes!

Nice one! 

Any problems with oscillating tubes under test?

[BU508A]

Is there anybody in here, it seems to be pretty dead to me 

I guess I'm nobody. 

https://www.imdb.com/title/tt0070215/   

[VK5RC]

When I repaired my Tek 545, I built the uTracer tube tester from https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
You need a PC to connect it to but it then graphs the tubes, the source/sink unit is relatively easy to build but getting all the different tube sockets and wiring them, with ferrites was challenging! Overall I am very happy with it - seems more useful than typical testers.
I also agree tubes are generally quite reliable - much more so than electrolytic capacitors. My tek had a shorted electrolytic and a buggered rectifier tube.  I think there was one other dead tube out of multiple tens of tubes!

Nice one! 

Any problems with oscillating tubes under test?

No, there were lots of inductors on all the wires. It doesn't do a high frequency test.

Re pulling tubes, the scope looked like it had been used as a chicken coup, every tube socket/tube/HV lines etc etc was filthy. Here is the old post https://www.eevblog.com/forum/repair/restoration-repair-of-tektronix-545/

[med6753]

When I repaired my Tek 545, I built the uTracer tube tester from https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
You need a PC to connect it to but it then graphs the tubes, the source/sink unit is relatively easy to build but getting all the different tube sockets and wiring them, with ferrites was challenging! Overall I am very happy with it - seems more useful than typical testers.
I also agree tubes are generally quite reliable - much more so than electrolytic capacitors. My tek had a shorted electrolytic and a buggered rectifier tube.  I think there was one other dead tube out of multiple tens of tubes!

Nice one! 

Any problems with oscillating tubes under test?

No, there were lots of inductors on all the wires. It doesn't do a high frequency test.

Re pulling tubes, the scope looked like it had been used as a chicken coup, every tube socket/tube/HV lines etc etc was filthy. Here is the old post https://www.eevblog.com/forum/repair/restoration-repair-of-tektronix-545/

Yep, I've seen your thread on the 545 restoration. I agree that the tubes needed to be pulled to clean it. I had to do the same in sections of my 535A. But I made sure the same tubes were installed back into the same location that they removed from. Especially tubes with unique Tek P/N labels indicating specially aged or matched pairs.   

[BU508A]

No, there were lots of inductors on all the wires. It doesn't do a high frequency test.

If working with high impedance circuits, even if not intended for higher frequencies,
just noise can be sufficient starting oscillating. But if you have assembled on all wires
lots of ferrites, you should be save. 

[Specmaster]

Oh goody, there is some activity here to read, I was sitting here bored waiting for the arrival of a battery so that I resume the calibration of the 4503 safe in the knowledge that I would risk losing it when I disconnect the old battery, hang on the doorbell just went. It was the postman and still no battery  It was meant to be here Friday, drats I'll have to go out now and get some food in before I do anything else. I would have gone before but nobody else is dressed yet to answer the door, and I was scared that if I went out that there was a risk to any parcels left on the doorstep disappearing 

[bd139]

Post is fucked at the moment. I'm seeing 2-3 days extra on everything. I just got my Elecraft K160RX kit and some LR44 batteries a few minutes back. Something to do at last 

After much deliberation on stoves I decided to skip the Svea one. This is for casual use rather than expedition, mostly to avoid having to spend hard on a hotel during peak season by dossing on a camp site or somewhere illegal on the sly. Thus it'll get used a couple of times on a trip for some bacon and eggs for breakfast, some oats and coffee and that's about it. Fond memories of my Trangia which I have been informed by my mother "was chucked out years ago because you didn't clean it properly and it started to smell funny" resulted in me ordering a Trangia Mini kit as it's easy to pack and carry on a day hike and an interesting firey distraction 

[Saskia]

rats. I gave away the 50 kg acetylene, 50 kg O2, 10 kg N2O bottle and the associated nozzles and stuff. Should have been sufficient to heat up my pea soup.
On a different note, I need to get hold of a dutch oven and some wooden box.

[bd139]

I think I'd just spend all day blowing shit up if I had an acetylene cylinder lying around 

Actually I think I'd get a rodentator and soup it up a bit. Probably more fun than with propane.

[Brumby]

I can see someone some here is are going to take that as a challenge.

Capacitors be afraid ..... be very afraid.


The rest of us be prepared to dodge flying foil...

[worsthorse]

So I am digging into the S38B. Nope, not TE, so I won't post more than this here, lest I incur some denizen-of-the-thread wrath...   

Here it is, out of the packing box. Manufactured, circa 1953:



That smear at the bottom of the chassis is the shellac used to secure a label. That's also where the isolation transformer will be mounted when I get to that step.  The smear will be gone before I finish cleaning the top side tomorrow. Then I flip it over and start working underneath. That will involve mostly removing dirt while I inspect the wiring and parts I hope not to replace.  Some guys actually pressure wash stuff like this, others use a dishwasher.      Not my cup of tea.

I don't see a power transformer which tells me immediately that's a series string receiver. I'll bet the audio output tube number starts with "50" and the rectifier starts with "35". The metal tubes probably start with "6" or "12" but utilize a split filament. And inline with the tube filaments probably a good sized power resistor. The tube filaments will add up to something less than 110VAC and the power resistor to make up the balance equaling 110VAC. 

 Given that it's a series string receiver one side of the AC line will be tied directly to the chassis. And I'll bet the line cord is still non-polarized. An isolation transformer is MANDATORY in order to safely work on that receiver. Depending on which way you plug in the line cord there will be 120VAC on the chassis unless an isolation transformer is used. 

Edit while I go......pulled up the schematic. Confirmed, series string receiver with one side of the AC line tied to chassis.

Also, you must make absolutely certain upon reassembly that no metal portions of the chassis are exposed on the cabinet which could shock the user. (except the antenna terminals which SHOULD be isolated)

Personally I hate that type of design because of the dangers but it was a cheap way to avoid the use of an expensive power transformer.
   

Yup, the S38 is a death trap. 

Although cabinet is isolated from the case, as are the switches and antenna input, it is still way too easy to kill someone or release the smoke by plugging it in wrong.  I am installing an isolation transformer (will be mounted on that blank spot on the chassis), inline fuse, and polarized plug (overkill? of course) before I power it up.  Even then, first power up will involve an external isolation transformer, you know, just in case I screwed something up.

And yup, all the paper and electrolytic caps will be replaced. I have the paper replacements on hand and a multi-section electrolytic on the way.  It doesn't look like I have to restring the dials but I have the proper cord if I do.  That will probably be the most difficult task on the list.

[Specmaster]

I think I'd just spend all day blowing shit up if I had an acetylene cylinder lying around 

Actually I think I'd get a rodentator and soup it up a bit. Probably more fun than with propane.

By the look of it, its more damaging to the lawn than the mole is 

[Saskia]

https://youtu.be/Zk-kQSz-Qv0
 

[mnementh]

Is there anybody in here, it seems to be pretty dead to me 

I guess I'm nobody. 

med's not dead... he just smells that way.   

mnem

[Specmaster]

Is there anybody in here, it seems to be pretty dead to me 

I guess I'm nobody. 

med's not dead... he just smells that way.   

mnem

Meds warming his CRV up for a long trip North to see the dragon, and sort his scaley arse out 

[mansaxel]

I'm just waiting to see what the NHS staff do to Jeremy Hunt if he ends up in an NHS bed anytime soon. Going to hospital is always a risky thing, doubly so if you've systematically worked at making everybody who works there your enemy.

There’s something utterly comedic about it 

Looking at Svea stoves at the moment. Proper rollercoaster day. It was land rovers earlier. This is what happens when the TE listings are naff!

The Svea is cute. I've got an Optimus 111 with Swedish MoD markings, as part of a canteen kit-in-a-box for 10 people, also military. (Kantin 10B/S) And, of course, two Trangia 25 stoves, one with butane/propane burner add-on.  And some kerosene lights. And matches, and fuel.

[mnementh]

 

mnem
 

[med6753]

Is there anybody in here, it seems to be pretty dead to me 

I guess I'm nobody. 

med's not dead... he just smells that way.   

mnem

Meds warming his CRV up for a long trip North to see the dragon, and sort his scaley arse out 

Meh.....not worth my time or effort. But he should watch out for that cruise missile.