Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > International Vintage Televisions

We appreciate your help

in keeping this site going.
 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old 09-02-2022, 01:08 PM
phonotone phonotone is offline
VideoKarma Member
 
Join Date: Aug 2022
Posts: 2
21 inch Austrian TV (Hornyphon) working agian

I reported in my introductory message as a new member that I had high voltage problems with my 21 inch, 1957 Austrian Hornyphon (a Philips subsidiary) set. I was finally able to trace the problem and get the set working again. This may very well be the only working set of this kind in the US. It's a 220V, CCIR 625 lines / 50 fields TV.
The fault was in the filament circuit for the high voltage rectifier tube (DY87 = 1S2A). The filament voltage is generated by a single winding of high voltage cable around the core of the flyback transformer, quite a common way to generate the heater voltage superimposed on a 17KV high voltage potential. The circuit diagram showed a 1.4 Ohm resistor in series with this winding. I disassembled the high voltage rectifier tube holder with socket and found the resistor glued into the center hole of the tube socket, and the tube socket pressed into the plastic insulator tube. It was a wire wound resistor, the wire being thinner than hair. The resistor had become open, unfortunately. I was not able to extract and repair the glued in resistor, but I was able to shunt it to get the set working again. I will have to find a more permanent solution, however. In the past, I would have looked for a replacement tube socket / high voltage tube holder. This part is impossible to find these days. I may have to resort to 3D printing it, keeping 17KV of anode voltage in mind, and make a 1.4 Ohm wire wound resistor.
Attached Images
File Type: jpg 21inch hornyphon 1957 smaller.jpg (61.0 KB, 51 views)

Last edited by phonotone; 09-02-2022 at 01:11 PM.
Reply With Quote
 



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:12 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.