Test Equipment Anonymous (TEA) group therapy thread

[tautech]

OK, more specific Old Tek Junk Junkie. 

You do good work Med and I enjoy reading your battles and fixes. 

[Specmaster]

OK, more specific Old Tek Junk Junkie. 

You do good work Med and I enjoy reading your battles and fixes. 

I think you speak for us all on that topic. I enjoy the repairs, always something to be learnt but personally I'd rather be repairing something new to me, or something that will earn a buck or two help fund my TEA, than keep repairing the test gear that I should be using [emoji4]

Perhaps one day I too might be able to get all new kit but for now I'm happy with kit that is 30 years or less old with low hours of use on them. My oldest bits of kit are older but seldom used, their RF signal generators but judging by their condition have had very low usage in their life, [emoji106]

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[med6753]

OK, more specific Old Tek Junk Junkie. 

You do good work Med and I enjoy reading your battles and fixes. 

I think you speak for us all on that topic. I enjoy the repairs, always something to be learnt but personally I'd rather be repairing something new to me, or something that will earn a buck or two help fund my TEA, than keep repairing the test gear that I should be using [emoji4]

Perhaps one day I too might be able to get all new kit but for now I'm happy with kit that is 30 years or less old with low hours of use on them. My oldest bits of kit are older but seldom used, their RF signal generators but judging by their condition have had very low usage in their life, [emoji106]

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If your intention is to turn an item around and sell it to fund other purchases then that makes total sense. But I purchase and keep because that's what I want in my collection. So I don't mind if I gotta fix it. And if something does break while I'm troubleshooting other equipment I have backups.

Edit....the 475A is back in the case and it's been running for hours and channel 1 is working fine. 

[GregDunn]

UFO wasn't too bad. There was an internal logic, and that and physics weren't ignored form the sake of the current episode's plot. In that sense it was a live action follow on to Thunderbirds.

Basically I found UFO to be entertaining for one or two episodes. But Space 1999 made me want the throw something at the TV after 15 minutes.

Same here - 1999 reached its nadir with the "green tongue monster" episode.  I only ran across it by accident, because there's no way I'd intentionally tune in to that piece of poop.

UFO actually had some very good moments - when people have todo their job, make hard choices and it destroys a family or a relationship, that's not formulaic TV.  It also eschewed the "monster of the week" or "melodrama of the week" plots, which kept even the lesser episodes from being disasters.

[mnementh]

   You mean this guy? Yeah... some truly LAZY setbuilding coupled with with "spew & a half" acting... and this from a guy with fond memories of the "K-9 years" on Doctor Who... 

mnem
*currently just starting on the David Tennant years with my kids*

[0culus]

Received a goodie box of 7k series plugins. Pair of 7A26 amplifiers, a 7A13 differential comparator, and a 7A22 differential amplifier. Also a P6046 differential probe. Pics to come this weekend.

...now I need P6055 probes for the differential plugins. 

[bsfeechannel]

We call vacuum tubes valves because they control the flow of electrons I guess [emoji16]

You call them valves because Fleming called them valves.

[Specmaster]

We call vacuum tubes valves because they control the flow of electrons I guess [emoji16]

You call them valves because Flemming called them valves.

That maybe, but why did Flemming call them valves is the question then and being purely logical, might it be that he called them valves because of their ability to control the flow of electrons in a similar fashion to valves controlling the flow of a liquid or gas?

[bd139]

We call vacuum tubes valves because they control the flow of electrons I guess [emoji16]

You call them valves because Flemming called them valves.

That maybe, but why did Flemming call them valves is the question then and being purely logical, might it be that he called them valves because of their ability to control the flow of electrons in a similar fashion to valves controlling the flow of a liquid or gas?

Well the first flemming valve was only a rectifier so I suppose that makes sense. I’m not sure it does for a triode etc. That’s a little more complicated due to the characteristics of the device. Transconductor probably made more sense (along with the FETs) but I don’t think they had a grip on network analysis then or had come up with that word. Ugh got a Laplace flashback then ... shudder.

Incidentally, one of Flemming's prototypes was featured in the science museum. I got a snap of it the other day:



According to the label it was actually donated by him personally.

Weird that everything we're doing started with that.

[bsfeechannel]

That maybe, but why did Flemming call them valves is the question then and being purely logical, might it be that he called them valves because of their ability to control the flow of electrons in a similar fashion to valves controlling the flow of a liquid or gas?

Fleming's 1905 US Patent application:

https://patentimages.storage.googleapis.com/23/09/50/6d4980acdfed12/US803684.pdf



Straight from the horse's mouth.

[bd139]

There you go. Let’s all call them valves now 

[Specmaster]

We call vacuum tubes valves because they control the flow of electrons I guess [emoji16]

You call them valves because Flemming called them valves.

That maybe, but why did Flemming call them valves is the question then and being purely logical, might it be that he called them valves because of their ability to control the flow of electrons in a similar fashion to valves controlling the flow of a liquid or gas?

Well the first flemming valve was only a rectifier so I suppose that makes sense. I’m not sure it does for a triode etc. That’s a little more complicated due to the characteristics of the device. Transconductor probably made more sense (along with the FETs) but I don’t think they had a grip on network analysis then or had come up with that word. Ugh got a Laplace flashback then ... shudder.

Incidentally, one of Flemming's prototypes was featured in the science museum. I got a snap of it the other day:



According to the label it was actually donated by him personally.

Weird that everything we're doing started with that.

Well, I was only making a guess at its origin[emoji4] but surely with all valves / tubes if you don't connect the grids you are effectively left with a rectifier? It is weird when you look at the humble origins of what we do now I agree, look at the first transistor for example. Often the first anything is totally unrecognisable to today's version of it. [emoji848]

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[Specmaster]

So it's official then, Fleming did call tubes valves after all, not a bad bit of deduction on my side there, get in! [emoji1787]

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[bsfeechannel]

There you go. Let’s all call them valves now 

The Russian call them radio lamps. Dispute settled.

[bd139]

Nyet! 

[PA0PBZ]

In Dutch they are called "buizen", that's tubes and I'm sure they are called just tubes in English too somewhere.

[med6753]

Vacuum tubes! 

[Brumby]

In Australia - they're valves.

But we still had VTVM's here - and we knew what they were.

[med6753]

Speaking of VACUUM TUBES and VTVM's   ...decided to start work on the Heath V-7A.

Looking pretty sad. Duff meter. Filthy cabinet and front panel. Going to completely break it down and spray paint the cabinet and clean the front panel along with replacing the meter.



First look inside. Very clean and appears well built. A filter cap and one wax tubular cap will have to go along with the selenium rectifier. No battery corrosion. Will check all the carbon comp resistors and the 9.1 ohm resistor in the ohms circuit that Gorillas always burn out when they try to do resistance checks with power on. Going to assume for now that the rest of the precision resistors are OK. They typically maintain their value.

[bd139]

Looks pretty good that one. Whoever assembled mine did it with a fecking clothes iron or something 

[med6753]

Well whoever owned this V-7A was no Gorilla.  Other than the parts mentioned before which are automatic replace just one carbon comp is reading a little high. 3.9M vs 3.3M. So that will be added to change out list. The 9.1 ohm resistor that always seems to get burnt is reading 9.04 ohms.  No Gorilla here! 

Front panel has been cleaned along with the knobs. Case painted, currently drying. Going to reassemble it for now because the parts will need to be ordered.

Edit, I'll post a pix once I get it reassembled.

[bd139]

Sounds great. If that’s the 3.3 meg on the input side of the 12au7 then that’s normally high. Not sure why but all of the ones I’ve had were high. Probably shitty carbon comps.

Just managed to bodge my Norcal 40A to get 5W out instead of two. Melted the collector choke to the board  . I am today’s gorilla 

[med6753]

The cosmetic portion of the V-7A restoration is done. The electrical portion pending receipt of replacement parts. A combination of an American VTVM and an English "Valve Voltmeter" meter. I hope it's a good relationship.  My last relationship with an English redhead wasn't so good. 

Anyway.....that's the proper DC probe with the 1MEG resistor in the probe tip. And I took the top handle off my older V-5 VTVM. That guy is going into retirement and long term storage.

[bd139]

Looks good 

[bitseeker]

Speaking of VACUUM TUBES and VTVM's   ...decided to start work on the Heath V-7A.

Looking pretty sad. Duff meter. Filthy cabinet and front panel. Going to completely break it down and spray paint the cabinet and clean the front panel along with replacing the meter.

The cosmetic portion of the V-7A restoration is done. The electrical portion pending receipt of replacement parts. A combination of an American VTVM and an English "Valve Voltmeter" meter. I hope it's a good relationship.  My last relationship with an English redhead wasn't so good. 

Anyway.....that's the proper DC probe with the 1MEG resistor in the probe tip. And I took the top handle off my older V-5 VTVM. That guy is going into retirement and long term storage.

Added to POI.