GEC BT302 from Bideford - UK Vintage Radio Repair and Restoration Discussion Forum

newlite4 · 7th May 2008, 3:09 pm

This is the BT302 television rescued from the Bideford recycling depot last autumn. It had been repaired at various stages of its life, it was now time to put things right.
The U25 EHT rectifier (V11) had corroded, broken wires and was no longer useable, this was replaced along with N308 line oscillator (V12) which was arcing internally (when the horizontal hold was adjusted) and U339 boost diode (V13) for good measure. A section of the mains dropper needed replacement (R80) as did the RF bypass cap (C155), consequentially the mains on/off switch was seized-on until freed-up.
On test, the raster took on a rather hour glass shape which improved over half an hour after which the reservoir and smoothing cap can started to vent, OK replace C154/C153. The raster appeared somewhat non linear and cramped, I decided to recap the timebase board to give the struggling line and frame timebases a fighting chance.
I now had a decent test image from the front-end to the screen, but no sound. The speaker connector plate needed rebuilding (I used mini lucar connectors here on a fresh tufnol plate) also the audio output transformer needed replacement since the primary was O/C this was because of "that" capacitor (C85) which was swiftly replaced to avoid any more costly and time consuming damage.
Well, the set "goes" but may need further refinement in the future. Its future is more secure now that it is a worker.
Neil

Tim · 7th May 2008, 3:57 pm

Although I am not generally interested in the TV side of things, that's a good looking set saved. Well done.

Councils in Devon and Cornwall seem to be much more "civilised" when it comes to "Re-cycling" stuff from their tips than other councils I could mention( but thats for another thread...........).
For example North Cornwall District Council have a "mend and resell/distribute to the needy scheme" How very laudible.

7th May 2008, 3:09 pm	#1
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	GEC BT302 from Bideford This is the BT302 television rescued from the Bideford recycling depot last autumn. It had been repaired at various stages of its life, it was now time to put things right. The U25 EHT rectifier (V11) had corroded, broken wires and was no longer useable, this was replaced along with N308 line oscillator (V12) which was arcing internally (when the horizontal hold was adjusted) and U339 boost diode (V13) for good measure. A section of the mains dropper needed replacement (R80) as did the RF bypass cap (C155), consequentially the mains on/off switch was seized-on until freed-up. On test, the raster took on a rather hour glass shape which improved over half an hour after which the reservoir and smoothing cap can started to vent, OK replace C154/C153. The raster appeared somewhat non linear and cramped, I decided to recap the timebase board to give the struggling line and frame timebases a fighting chance. I now had a decent test image from the front-end to the screen, but no sound. The speaker connector plate needed rebuilding (I used mini lucar connectors here on a fresh tufnol plate) also the audio output transformer needed replacement since the primary was O/C this was because of "that" capacitor (C85) which was swiftly replaced to avoid any more costly and time consuming damage. Well, the set "goes" but may need further refinement in the future. Its future is more secure now that it is a worker. Neil Attached Thumbnails __________________ preserving the recent past, for the distant future.

7th May 2008, 3:57 pm	#2
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: GEC BT302 from Bideford Although I am not generally interested in the TV side of things, that's a good looking set saved. Well done. Councils in Devon and Cornwall seem to be much more "civilised" when it comes to "Re-cycling" stuff from their tips than other councils I could mention( but thats for another thread...........). For example North Cornwall District Council have a "mend and resell/distribute to the needy scheme" How very laudible. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."