GEC BT452 Television.

[Restoration73]

Pristine inside. First light shows a very bright AW47-91, although the
field timebase is running at the wrong speed.
Note this is the early 405 only version, none of this "convertible" or
"dual standard" nonsense here.

[FERNSEH]

This 1962 model was a pure Radio and Allied Industries design (Sobell) unlike the BT448 series which was also made after the takeover of GEC Radio and Television by R & A.
Your BT452 was made in the R & A works in Hirwaun, Wales. The Coventry made BT448 still incorporated a few design elements of the older GEC pre 1961 models.
As well as the "convertible" BT452, dual standard models BT452DS and BT452DS-T also appear in the Radio and Television books.
A McMichael "Black Rose" version was also made. Same cabinet shape, just a few trim differences.

DFWB.

[Restoration73]

It's light enough to be a portable, lighter than the earlier TPS173, which uses a similar
incremental tuner. There are two bungs on the side of the cabinet for the non-existent
standards switch and UHF tuner, with an un-punched hole for uhf aerial on the back.

[Heatercathodeshort]

Nice receivers with a reliable LOPT [hands crossed...] Excellent picture and no nasties. The double sided print is a doddle once you remember to unsolder the components from the component side and not on the 'solder' side as is usual. Use a temperature controlled iron and melt the solder thoroughly before lifting the component lead with a hook ended 'picker'. One of Radio and Allied Holdings best.
Strange how these addresses are burned into your brain. For a while the spares dept was situated at 719 North Circular Road, London NW2. Tel: GLAdstone 6454.
On many occasions I used to make the trek along the old North Circular Road A406 to pick up urgent spares.
That was back in the days when the 1930's road was crammed with factories and was a frenzy of industry and employment, many of which were connected with the electrical industry. Happy Days! John.

[Restoration73]

Now completed - a few resistor values had changed. If anything there is
a tendency to excessive width, although I can find no fault with the line TB.
The picture is better than shown, in fact very good for a basic set.
The line displacement is down to my video source but I hope to have another
converter soon.

[Heatercathodeshort]

Great picture! Not a lot to fail with this series. Many examples were a bit 'odd' with very slight foldover on the left from new. John.

[Restoration73]

Oh I'm glad it's not me then. Normally excess width is poor eht regulation but not here.
I was able to move the picture a bit more to the right by unsoldering the 300pF from the anode of the sync sep to ground, although this means line sync may tear with weak signals that is not a problem, in fact the set gain is high. I am thinking of construction the optional flywheel sync board as it only has a few passive components.
Now to do the other 12 sets.......

[BGmidsUK]

I've just got round to reading some threads I opened a while ago (slow computer, distracted by the cats etc.) and found this again.
Lovely little set and excellent results.

The "excessive width" issue seems to be common; I've seen many sets like this. More recent sets don't even provide a means of adjusting the width without access to service menus, much to my annoyance! I wonder if the HT is a bit high .. or would the increased EHT (over)compensate for this?


Brian

[Heatercathodeshort]

Check the position of the line linearity sleeve but don't push it in too far! J.

[Focus Diode]

Very nice sets indeed. I used to have a tatty McMichael MT763 DS-T fully dual standard model. The IF panel which included the system switch is wired in that version. I'm sure the speaker is on the opposite side to the BT452.

Cheers,
Brian

[The teleman]

Hi
Great set ! If your still getting excessive width it could be due to the PY33 rectifier. I think the original is PY32 the PY33 with give slightly increased HT

All the best
Chris