Baird T163

[EF80TVVALVE]

I recently purchased this Baird T163, something that's been on my list for a long time so I was very happy to have found one. This particular set has obviously lived a full life and looked as though it deserved its retirement once it was upgraded to a 12 inch set. There were quite a few bodges within the set, some resistors bridged across, some resistors missing and a string of RS resistors replacing an O/C one. The smoothing caps have also been bodged with an extra can fitted loosely underneath.

The task began and I've spent a fair few hours putting the set back as per schematic, ridding it of all these bodges it has suffered from throughout its life. I've changed quite a few caps as many were giving up whilst powering the set, getting hot and shedding wax and I didn't want these to also cause damage to other components.

The set now powers up reliably but my current problem is a lack of (or no) EHT. The frame stage sounds like it's running, at least there is an audible low frequency (70Hz or so) coming from the strange transformer arrangement which varies with the hold control but there is currently no sign of life from the line stage. Ive tested both KT36 and they test okay and close to spec.

I'll have to dig my scope out next and have a look what's going on around the EB41 and KT36. I've had trouble with the exact same rimlock sockets that the EB41 is held in where the pin breaks away from the valve pin contact so I'll have to check this one for this fault too. I'm working from the ERT sheet which also gives resistances of all windings, I've also checked these which check out fine and the circuit is also exact to the schematic too.

HT seems a bit low (40v down) and it starts to drop as the set remains running, I'll be restuffing the smoothing cans as I suspect these and they're already bulging with one section removed from circuit and replaced with the later multican.

It's been quite a challenge so far, I don't think I've ever worked on such a bodged up set before so it's quite an experience! I just hope the CRT which is a GEC flat faced type is good.

[slidertogrid]

That is a find as you say it looks as if it had a long life! What we now see as bodges were probably just an 'economic repair' back then! I will follow with interest!
My Grandfather had a Baird Townsman when I was really young. I remember watching Bill and Ben on it. I don't know what happened to it but I looked for one for years.
The one I eventually found beat yours as far as bodges went... When I arrived to collect it at first I was delighted as the cabinet was superb but looking inside I found someone had cobbled a '50s Bush chassis into it! I told the seller I wasn't interested as the set was ruined. God only knows why it had been butchered like that!
I suppose when it was done the set was just an old telly, I do wonder why they stripped what presumably a new Bush! They must have really liked the Baird cabinet. Some time later the Baird cabinet was re-listed empty. I only hope someone had a chassis and tube for it rather than the fish tank brigade with a pot of paint !
Good luck with your restoration! Do you think it will be possible to save the mask?

[EF80TVVALVE]

Thanks for your comments Slidertogrid, this set had been in the same family from new so it was nice to hear some history of the set. I should ask the vendor if any of his relatives were in the trade because some of the repairs are certainly the sort of stuff you'd do to your own set to keep it going, I doubt similar repairs would have been done for a customer. As you say, they were just economical repairs, bits laying around etc but the circuit had been altered somewhat too and I also wonder if they had the same problem as I'm having now! I think the screen mask is too far gone, I've managed to remove it and cut away all of the stretched out rubber that fits around the CRT, leaving just the frame but it has distorted very badly and no longer has any support of itself. I'm hoping I can find something suitable as a replacement or possibly make one up instead.

Interesting to hear of the Bush chassis fitted to that example, in my opinion the Baird cabinets are very nice but the chassis does feel a bit cheap, it's very flimsy and certainly isn't of the same build quality as the cabinet but I'm sure it's a good receiver when working properly. From the styling of the cabinet I could understand why somebody would want to keep hold of it.

Cheers
Bren

[PJL]

I posted this about a Baird chassis some time ago... it had a Mullard tube but may never have worked of course! https://www.vintage-radio.net/forum/...d.php?t=187998.

[EF80TVVALVE]

Interesting stuff PJL, I wonder if it's still there? It would yield some useful spares! I believe these sets also had a CRM92 fitted, I don't think these nor the GEC tube have a very good reputation!

[FERNSEH]

I'll be watching this topic with great interest. I don't believe these were bad sets but did seem to be the victim of bodgers. It's not as if the circuits are especially complex, fairly straight forward design really.

DFWB.

[EF80TVVALVE]

Thanks David, they are a nice thing really and I mean no disrespect to them when I say the chassis is a bit cheap. It just strikes me odd that they'd make such a lavish cabinet but really scrimp back on the actual workings of the set. Hopefully I can find some time tonight to look around the line stage and suss out what's going on, it'll be nice to get something on the screen.

The set also came with two original aerial/mains leads which was a nice addition, I'll have to take a photo of them although they are quite plain with just a bakelite box containing two inductors inside.

[EF80TVVALVE]

I've managed to get a quick look in with the scope this evening. The EB41 is obviously doing its job and is providing the KT36 grid with a waveform which doesn't look too bad although still no EHT. I need to find where the HT rail is losing its volts as it started off around 210v (70v down from data) but dropped to 160v before I decided that I should really turn it off as something isn't going to enjoy dumping that amount of voltage. Part of me is hoping that having the HT return to its normal working voltage will see some life from the LOP stage.

[stevehertz]

I had a Baird Everyman that must have been the cheapest commercial set made. They'd skimped so much, the frame oscillator and drive circuits had been condensed into one, resulting in a non linear drive waveform and a picture whereby the test card circle appeared strikingly egg shaped left to right. So a person walking across the screen would transform from anorexic to tubby in five paces. Nonetheless I loved that little set, so dinky.

[EF80TVVALVE]

Interesting stuff Steve, I'll have to look up that circuit as it's not something I've seen before. It looks as though Baird liked to do things a bit differently to other manufacturers, I wonder how popular these sets were as there doesn't seem to be many survivors of the portables now.

[FERNSEH]

Steve Hertz wrote: "I had a Baird Everyman that must have been the cheapest commercial set made. They'd skimped so much."

The signal circuits of the Baird T29. Despite having only having three RF amplifier stages they found it must have sufficient gain to warrant an attentuator in the aerial input.
Does the T163 have a similar RF circuit?

DFWB.

[mark pirate]

I wonder how popular these sets were as there doesn't seem to be many survivors of the portables now.

They are certainly not common, probably scrapped once the CRM92 failed!

I have the later T164, it actually restored quite well, but the Mazda airbag is as flat as can be

Cheers
Mark

[EF80TVVALVE]

Hi David, the T163 has a pretty standard Z77 RF strip, no attenuation either. It must have been quite a sensitive set relying on the mains aerial though. Mark, a shame about the CRM92, hopefully you find a replacement for it. It's a shame scrappy sets aren't as common as they were 10-15 years ago, I'd feel quite bad taking a tube from one good set for another despite how common the donor set could be!

[Panrock]

Originally Posted by EF80TVVALVE

Interesting to hear of the Bush chassis fitted to that example, in my opinion the Baird cabinets are very nice but the chassis does feel a bit cheap, it's very flimsy and certainly isn't of the same build quality as the cabinet but I'm sure it's a good receiver when working properly. From the styling of the cabinet I could understand why somebody would want to keep hold of it.

Exactly my thinking when I decided to make this 'cut 'n shut job'. http://www.radiocraft.co.uk/402.htm

In this way I was able to put together everything I wanted in my 'main' vintage television set. Namely:

• A console cabinet with a commanding presence in the room.

• A separate internal valve amplifier and a large speaker, to do justice to the high quality AM sound.

• A DC-coupled vision output, for true black level.

• An earthed chassis and mains transformer.

Steve

[EF80TVVALVE]

Hi Steve,

It was nice to revisit that build you completed, I read it originally several years ago now and I'm still amazed by the final quality of the set. Do you still use the set much? It's a shame in a way it has the Baird sets weren't quite as luxurious as their cabinets suggest but I'm sure they had their reasons and I can imagine a nice looking cabinet would have been high on the list for many purchasers at the time. The sets would probably have been prohibitively expensive should they have also gone to such lengths internally but I'm sure the sets still gave good pictures when new.

I haven't done much to the 163 over the past few days but I did test the valves just to be sure none of them have a short and pulling the HT down, all are okay bar the DH63 which has a slight H/K short although it did briefly show quite a bad short when first testing. Some caps are on the way to rebuild the original smoothing cans and I can then do away with that loose one hiding under the chassis.

[Panrock]

Thanks for the nice comments Bren. It's worth mentioning the he 12-inch tube shown in that project has since been replaced by a 'harder' one, out of another TV24. The original is now available free to a good home (must collect though).

Steve

[mark pirate]

Mark, a shame about the CRM92, hopefully you find a replacement for it. It's a shame scrappy sets aren't as common as they were 10-15 years ago, I'd feel quite bad taking a tube from one good set for another despite how common the donor set could be!

Sadly, I have been searching for about 10 years, I did manage to find a scrap Ekco that was way beyond restoring, but the CRM92 was just as bad as the one in the Baird.

I might try to fit a Mullard, I do have a 6.3 volt filament transformer somewhere.....

Cheers
Mark

[EF80TVVALVE]

Hi all,
Just a quick update with the Baird, I've restuffed the smoothing caps today which has taken a fair bit of time, it's much more neat in that area under the chassis now with no loose and dangling parts. I've given it a quick test and found it to still have low HT on the line feeding the focus coil and time bases. Removing the anode cap of the KT36 on the LOPT raises the voltage back to a more normal level so it seems the fault is in this area, either a problem with the KT36 circuitry or it isn't being driven correctly from the EB41 are my initial thoughts. I'll give it more of a look over tomorrow as it's quite late now but it's a step forward pin pointing where the HT is being dragged down.

Cheers
Bren

[EF80TVVALVE]

So this set is beginning to turn into a real head scratcher, it's obvious from the first few posts that the set has been bodged quite a bit and I'm beginning to now doubt whether the set was even working before being stored away or if someone had been attempting repairs and decided to call it quits.

I've been looking at it for most of today, I wasn't happy with the groan coming from the frame blocking TX/frame scan poles, it just didn't sound right at all and I don't think anything should even be audible from this component, it also gave more doubt when turning down the frame hold control and I could hear some possible arcing/ticking coming from either that or the KT36. It's evident that wires to this have been cut and re-attached in the past so after hours of going through the circuit and checking almost all components I decided to switch around the secondary windings to see if that changed anything.

After powering the set up again the groan had disappeared and I could now see the heater of the EY51 glowing which is the first time I've seen this since working on the set, there was some very quiet line whistle but the remaining fault of HT loss through the KT36 on the LOPT soon caused it all to dissappear.

I have to say I'm slowly running out of ideas on how to proceed next although a few hours rest and a look with some fresh eyes will probably help. I need to work out why the HT is dropping through the KT36 which now must be being driven quite well for the EY51 heater to glow. I don't doubt the valve itself as I've tested it on an AVO and there were no shorts but it seems to be drawing current and dragging down the HT.

If anyone has anything to chip in I'm all ears, I'll continue on it after a nice tea and maybe a, search for another KT36 just in case something internal begins to short out once the valve has warmed up.

[Rich Woods]

Originally Posted by mark pirate

Sadly, I have been searching for about 10 years, I did manage to find a scrap Ekco that was way beyond restoring, but the CRM92 was just as bad as the one in the Baird.

I might try to fit a Mullard, I do have a 6.3 volt filament transformer somewhere.....

Cheers
Mark

On the face of it that sounds a sensible idea, all things considered.