Featured
Latest
Thorn all solid sta...
 
Share:
Notifications
Clear all

Forum 139

B&W TV Thorn all solid state large screen B&W chassis

44 Posts
7 Users
15 Likes
586 Views
Nuvistor
(@nuvistor)
Posts: 4567
Famed Member Registered
 

@irob2345 I never saw a great change in focus with CRT’s using  electrostatic focus until the CRT was getting tired and then it was minimal.

Another fine restoration.

Steak and kidney pie and home made at that, lovely.

Frank

 
Posted : 11/02/2024 8:24 am
irob2345
(@irob2345)
Posts: 523
Honorable Member Registered
Topic starter
 

Yes on some mono CRTs (notably Philips) the focus pot setting determines if your raster is in focus in the middle, at the edges, or a compromise, for which you would aim. They do give the sharpest pictures of all the tube brands though. AWV CRTs were similar.

To get sharp focus on a Thomas CRT you need at least 19kV of EHT and the focus pot setting is more subtle.

I just ate my 2nd last slice of that pie, one more left for tomorrow night! Delicious! Well worth the trouble, I'll do it again!

 
Posted : 14/02/2024 8:42 am
irob2345
(@irob2345)
Posts: 523
Honorable Member Registered
Topic starter
 

I just had a look at the Philips C1 circuit. Not a lot of detail similarities to the Oz Thorn T series but it's conceptually similar, one might say "inspired by"! The T series is obviously a newer design.

I like the term "brushstrokes" to describe influences in a design. The C1 has a lot of Oz Pye brushstrokes - the minimalist "chassis" design is identical in concept, just smaller. Legend has it that it was actually designed at Pye Marrickville as a successor to the T26 but it was decided to keep the T26 in production up till colour, save the retooling cost and hand the design over to Philips (who owned Pye anyway). The Philips modular hybrid B&W chassis was getting a bit long in the tooth and expensive to make.

 
Posted : 27/02/2024 10:09 am
irob2345
(@irob2345)
Posts: 523
Honorable Member Registered
Topic starter
 

Though you might like to see just how minimalist the C1 chassis was. Just a sheet metal bracket, an aluminium extrusion and a PCB. PCB and heatsink folded up behind the CRT and flipped down for service access.

C1 Layout

Despite its simplicity, it was an excellent performer, reliable and easy to work on, not that we ever had to do too much to them.

 
Posted : 27/02/2024 10:31 am
Page 3 / 3
Share: