Is this a myth?

[Skywave]

Originally Posted by hannahs radios

Screen volts will change also maybe bias voltage also probably anode volts will increase slightly due to a decrease in the anode current

Ah! Now I understand your thinking: thanks for the clarification.

However, in 99% of cases, I do believe that your concerns in that direction are groundless.
Moreover, the process of switching at the mains outlet with the set on/off switch set to 'on' could be a valid method of testing and verifying the design and reliability of the set. The manufacturer could not guarantee that the user would always use only the set's on/off switch for the purposes of connecting / disconnecting supply power.

Al.

[boxdoctor]

From the mid-70s onwards, I would generally advise my customers to switch any domestic A/V equipment off at the wall socket (if a switch was fitted), if this was easily accessible and technically permissible, on the basis that a wall socket was easier and cheaper to replace than a specialised or obscure/hard to get switch integral with the equipment. It was also inherently safer, as there was certainty that the live feed was disconnected.
BTW, I believe the "InstanTv" sets referred to earlier were a modified Thorn 900 series chassis. The idea was abandoned due to cathode poisoning of the CRT by leaving the heater on continuously. Tony

[bikerhifinut]

Originally Posted by hannahs radios

Screen volts will change also maybe bias voltage also probably anode volts will increase slightly due to a decrease in the anode current

So how do you explain sets with separate on off switches, or on off switches on the tone control?
Or power amplifiers? All of mine have the power swich at the rear next to the mains power connector, needless to say once installed in the rack they stay switched on and everything is switched off at the mains socket............. I then remove the plug also.

[G6Tanuki]

Originally Posted by boxdoctor

From the mid-70s onwards, I would generally advise my customers to switch any domestic A/V equipment off at the wall socket (if a switch was fitted), if this was easily accessible and technically permissible

I bet they were really happy to be continually having to reset the clock on their VCR.

I, OTOH, spent plenty of time in the 1980s and through to 2015 installing A/V kit in higher/further-education and research environments - always removing the fitted plugs and hardwiring the kit to unswitched fused-spur outlets! Part of it was security [students would otherwise 'borrow' VCRs and TVs], the other part was service-reliability: I liked my kit to be continuously-powered if only to avoid the hassle of sending a tech out on an hour's job only to find someone had unplugged/switched-off-at-the-wall the supposedly 'faulty' equipment.

[boxdoctor]

Originally Posted by G6Tanuki

I bet they were really happy to be continually having to reset the clock on their VCR.

I would have thought it obvious that any VCR would not be on the same (swithched) socket as the rest of the kit for that very reason. Most later VCRs retained the time-keeping function by back-up cells/capacitor, or quickly acquired the correct time from the Teletext signal,

[hannahs radios]

Tob bikerhifinut alright you got me I don't know about that as I said what I said was just a few thoughts I had on the subject I'm no expert I just tried to think it thru

[Zelandeth]

Pretty sure this as others have said was simply due to CRT TVs with beam killer circuitry requiring the correct shutdown procedure to work correctly and protect the CRT.

Double-pole switches and inductive loads on RCD protected circuits can indeed by a pain - I've got an extension cord here which has a built in double pole switch, and at least one in twenty times when switching off a twin 125W 8' fluorescent light fixture using the switch on the extension would pop the RCD. Switching on, no problem, running, no problem, turning off however, *thunk* into darkness we go...

That fitting only gets used for testing lamps generally, so has just been fitted with a longer mains lead so I can actually reach a socket directly.

I've checked and re-checked everything and there is no fault condition there, even when subjected to a Megger still showed >20G ohms, so it's purely an inductive issue.

Historically we always tended to switch things off at the appliance in question, then whoever was the last person to go to bed was responsible for doing a walk round and making sure that everything that didn't absolutely need to be plugged in had the plug removed from the socket. TV was a pain as you had to virtually stand on your head to get to it, and I *did* in fact over-balance and fall down the gap between the wall and the big heavy arm chair in that corner one Saturday morning...

[hannahs radios]

One thing the public in general never got was that more modern transistorised radios need to be switched off at the set AND at the socket ( or unplugged if in Europe) because very often the switch on the set only disconnected the DC but left the transformer always on. Although my current boombox has station memory's wich rely on it being g plugged in all the time it has 30 memory's but there's only 2 stations I like!

[avocollector]

Originally Posted by GMB

]I had heard a rumour that there existed sets that had a warm-start system for valve heaters, so the set was endlessly on standby rather than being completely off.

Yep it's true. I recall late 60's ads for a Murphy/Richards set that switched on INSTANTLY rather than taking the 3 or so mins B/W TV's took in the 60's. The explanation was it kept the valve heaters on in standby (like modern valve guitar amps do) and so only needed to bring the HT up when the 'on off' switch was used.

[avocollector]

I must admit the legends/old wives tales of the old TV scene were great. Heard the one about how you had to leave the TV to cool down before moving it as otherwise the solder joints 'crystalised out' and fell apart. Or how about if you changed channels while it was switched on, it would wear out 'a lot faster' - one elderly relative of mine believed this to the extent that he turned it off AND let it cool down before changing channels!! Poor soul missed a lot of his favourite programs that way so in the end we bought him a modern (transistor) set and told him not to worry as it had no valves (fortunately he did NOT realise what the CRT was!!). Anyway this worked very well until visiting one week we noticed he was wearing a hat made of - yep you guessed it tin foil!! A neighbour who 'knew a lot about TV's' had advised him to do this. After talking to the guy it appears he had misunderstood a recent program about subliminal advertising and thought it meant that modern sets put 'voices in your head' by radio waves so the way to stop it was a tinfoil helmet, he too wore one as well and somewhere I have a picture of them sitting side by side in their 'TV gear'. Much as I'd love to show it to you all . . LOL

Interestingly the legends have not stopped with modern technology - there was some con man selling a 'special juice' you painted on the ic's in your guitar amplifier to give it 'that valve sound' on our local internet auction site not so long ago - LOL.

[Welsh Anorak]

We still get a lot of (older) customers worried about their new TV not having an on/off switch, and I can understand their concern about a glowing light in the corner of the room. However some fairly recent sets did have mains rocker switches which fail frequently, often burning up in the process. This was really more trouble than it was worth, though fun could be had with the irate customer furious that his newly repaired set now didn't work at all! "Have you switched it on, sir?"
Isn't it strange how many modern items take so much longer to boot up than an old valved TV ever did? Most old timers would put a Sky HD+ box to shame.
Glyn

[Biggles]

Yes, I agree, I find it ironic that most of my valve kit is up and running, bright eyed and bushy tailed, ready for action long before my Freeview recorder box has even got through half of it's boot up sequence. To be fair the Freeview box probably has a lot more to do in the same time.
Alan.