UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

1100 man · 5th Apr 2020, 10:32 am

Hi Luke,
Looking at the circuit diagram, the tube (CRT) heaters are fed from a winding on the line output transformer (Flyback transformer) as is usual practice. D94 & D96 on the diagram.

So if there is no orange glow from within the tube neck, the first question to ask is 'is the line output stage actually working'? The first thing I would do is measure the DC supplies that are produced by the LOPT. A bit difficult now you have dropped your meter!

If the 163V line is present across C2470, that would be a good indicator that there is life in the line stage.

I see the tube heaters have a fuse (1255 630ma) in parallel with a 1 ohm fusible resistor mounted on the tube base panel.

If the line stage is working and the above fuse is OK, check the tube heaters for continuity. It is possible that there is a difference in the pin connections on the flyback transformer and that the heater winding is not actually connected to where it should be!

Hope that helps

All the best
Nick

5th Apr 2020, 10:32 am	#2
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: Help with a Philips Anubis AAC Set Hi Luke, Looking at the circuit diagram, the tube (CRT) heaters are fed from a winding on the line output transformer (Flyback transformer) as is usual practice. D94 & D96 on the diagram. So if there is no orange glow from within the tube neck, the first question to ask is 'is the line output stage actually working'? The first thing I would do is measure the DC supplies that are produced by the LOPT. A bit difficult now you have dropped your meter! If the 163V line is present across C2470, that would be a good indicator that there is life in the line stage. I see the tube heaters have a fuse (1255 630ma) in parallel with a 1 ohm fusible resistor mounted on the tube base panel. If the line stage is working and the above fuse is OK, check the tube heaters for continuity. It is possible that there is a difference in the pin connections on the flyback transformer and that the heater winding is not actually connected to where it should be! Hope that helps All the best Nick