Old Tellies - How often should they be used?

[Tazman1966]

Hello All.

After having got my Dynatron (Pye 697) back to life (see separate thread nearby) and having persuaded my wife to agree to having the set indoors instead of the Philips G8 (also see another thread no doubt not very nearby!!!) it occurred to me that with sets of 30 years or more how much use should they get?

The G8 has been in daily use in our kitchen/diner for the last couple of weeks with no ill effect other than if it has been running for more than a couple of hours , it is noticably darker and a little softer and after hearing Lee's (Hunts Smoothing Bomb) horror story with his Dynatron - it had a big burn up on the LTB panel and promptly caught fire - I am worried about running them as regular sets.

What does everyone think?

Regards,

Tas

PS Sorry if this has been discussed before I joined but I couldn't find anything about it although I must admit that I didn't look very hard .

[dazzlevision]

Hello,

I run my collection of sets (housed in one room) for an hour every couple of weeks, to allow them to reach full operating temperature and thus drive off moisture and keep electrolytic capacitors formed.

Set with known unreliable line output transformers (e.g. Rank Bush Murphy pitch covered types) may well deteriorate over the years if not run, to keep them warm and dry. This may be why so many of them are u/s when you power up a set that has not been used for many years.

Of course, old sets are not designed with many failsafe features (such as lots of fuses, fusible resistors, flame retardent plastics, etc.), so I would keep an eye on them whilst they are running and at the first sign of abnormal operation, turn off and investigate!

You will find that whilst running very old sets, one will fail now and then, but it can usually be fixed. The big worry is that the line output transformer will expire, but I reckon that is more likely if it is only powered up very occasionally.

Regards,

Dazzlevision

[Heatercathodeshort]

Hello Taz,
The G8 is a very safe set and I have never known one to cause concern. The Pye 691/7 is another story and to be honest I would not be happy to use that set for long periods, particularly if left unattended. They did pop and bang a bit when in regular service. Don't get me wrong they are an excellent set and I liked them a lot when I sold them new.
Lopt, boost cap failure [S/C] and tripler breakdown caused a lot of overheating. The 691 was by far the best as far as reliability goes. Use it by all means but with caution. We are now more than 30 years on.....Oh I do feel very old........It seems like only last week. Regards John.

[Dr-Watts]

Can't speak for Philips tellies but I run my Decca Bradford every evening for a few hours. It's never been a problem and it keeps the bedroom nice & warm in the winter
The only time it was problematic I was in working in Japan, my Mrs turned it on late one night and one of the tuning caps in the Line Output stage passed away with such a bang that it woke one of the kids up in the next room.

When I got back from Japan, I was greeted with
'Your dinosaur's blown up!'

I say, use it and enjoy it, that's why I only have room for one, so it can be used on a regular basis; when I eventually get the GEC 2028 running nicely, you bet it's gonna end up in the bedroom.

The Dr.

[MALC SCOTT]

I have been using a 20 inch Rediffusion MK1 as an everyday set since 1973. Never been any problems, just the odd valve and a couple of triplers. I used to leave it switched on all night when i was a young lad and had been out boozing , my kids do the same now . Cheers, Malc

[Tazman1966]

Hello Chaps.

Thanks all of you for your replies.

...And so far so good .

John - I do remember as a kid several bangs & pops from our Invicta CT7056, and all of the things you mentioned happened too. The most startling one was LOPT failure - it scared my mum to see smoke coming out the back

I have told my wife not to leave the set unattended for any length of time, though, and if anything strange seems to be happening to switch off.

Regards,

Tas

PS I've put some more photos on the original thread - 'Dynatron help wanted' etc.

[channel405]

I run daily my 1958 Defiant set, sometimes for as much as five hours non stop cos there is nothing quite like a valve driven TV/heater combo! I replaced most of the caps, a few valves and about seven high value resistors and it seems fine so far despite spending the last 30 odd years in storage including a damp barn and the last eight years my attic.

Next project is a 1964 RBM dual standard set to help share the load, bit worried about the LOPT comments here though!

[Steve_P]

If it's a 1964 Rank Set, it's probably a Bush TV125 or it's Murphy V873 Version. They weren't quite as bad. Not that any Rank Dual Standard Sets were brilliant in this respect! There's things that can be done though....

Let me know what happens.

Cheers,

Steve P

[Hybrid tellies]

I try and run my Decca Bradford at least once a month for a few hours, and try not to leave it un attended. I also run my other two older mono sets (ITT/KB VC205 and RBM A640) for the same amount of time.
But as I have been off work for the last few weeks the Decca has been used more frequently and seems to enjoy the extra hours service.

I would heed everyone else's advice about the 697 chassis, run it by all means but never unattended. These things use to go up in smoke and flames even when they were fairly new, especially if they were fitted in Dynatron cabinets.

The Pye 697 chassis was not nicknamed, by many in the trade, as the fireraiser or firemaster without good reason.

The G8 is one of the better designs of the day and runs a lot cooler. But as all these sets are now over 30 years old it pays to be a bit cautious when using them.

[DoctorWho]

Interesting thread this, it's something I have wondered about myself. I mainly collect sets made before 1950, so some have mains EHT, some have RF EHT and some have Flyback EHT.

Funnily enough my wife informed me yesterday that we have 18 TV sets in the front room: well, hasn't everyone? ....

I tend to occasionally power the whole lot up at once, and let them run for about 20 minutes, I then turn off the mains EHT sets, especially as some have their original mains EHT transformers (the Pye D16T, Cossor 912 etc) and I don't want to over-do the strain on those. The others I will let run up to an hour or so, and then turn them off one by one. On these occasions you do not need central heating!
Other times I will just power up one set to actually sit and watch, I don't usually run them for more than an hour, and I take extra care with the earlier sets, usually not running them for more than 20 minutes a week maximum, whereas a later set, such as a TV22, I will use to watch a programme I want to see (such as Dr Who for example) and then just switch off when it's finished.

[Studio263]

I find this very difficult, there must be a balance between "too much" and "not enough" use though.
I try to run all mine (mostly B&O) at least once a year (but usually fail with the big and difficult to reach ones). I find the monochrome and 20AX-based sets take a while to "come up" but are then OK if used normally. The 30AX ones work as if they'd been on an hour ago, top marks there.
The older colour stuff can go either way, the really early ones (2600, 3400) seem to be OK but the last time I started up the 3500 (22" 110 delta, like a rich man's G9 in a lot of ways) it was absolutely fault riddled, frame collapse, no sound, instability in the IF's... Oddly the frame collapse / sound problem was caused by a defective EW modulator diode; you don't get faults like that on a BRC 1500!

In general I think it is better to use than not to, though we do use a "modern" set (1990 model year) for everyday viewing.

[Welsh Anorak]

Hi
I think if you are to use an old hybrid colour as a main set, then it makes sense to add a few modern safety devices if only to prevent it hurting itself!

A clever idea used by Tandberg (I think CTV1) was to have a heat fuse (effectively a bit of low melting point solder stretched between two points) by the line output stage so if your PL or PY got a bit hot and bothered it would melt and isolate the stage.

Putting the odd extra fuse in line with each HT line, and possibly the heaters, would be a good start, especially on the 697 which has virtually none! Compare that with the CVC5 series....
Also putting modern flameproof components in place of the boost and mains filter caps makes good sense - you can always keep the originals.
A fuse carefully mounted between LOPT and tripler (didn't Grundig use one?) will help protect the former from burning out, and a silicone EHT cap makes sense (easily salvaged from a duff modern LOPT).
One thing with the 697 is to ALWAYS remove the mains plug when not in use - carbonised tracks did used to happily keep on burning leading to much upset....if that's a problem consider moving the 'hot' fuse and connections away from that pesky PCB!
We do need to remember these sets were designed to work in a domestic environment - and did do, quite effectively. Although I do look at the G6 and wonder how it could ever have worked at all, let alone how surprisingly reliable it was!