16-08-2020, 02:02 PM
Peto-Scott continued to employ the stabilised line timebase circuit until the introduction of 110* CRTs in 1959. The later production models with stabilised LTBs employ a valve instead of the crystal diode. In the circuit shown in the attachment one of the diodes in a PABC80 is used, some sets used a diode in the EBF89 sound IF amplifier.
So more reserve power is needed if you wish to use a LTB stabilising loop and the jelly pot can supply plenty of of that. Many, many years ago a BRC 950 Mk2 came in for repair, evidently the last repairer had given up trying to fix the set. Someone had wrote inside the cabinet "died in 1968 of too much EHT". Of course the fault was in the stabilising circuit and it was a simple matter of replacing all the components in the LTB, the VDR width control and the feedback capacitor.
Geordie McBoyne.
So more reserve power is needed if you wish to use a LTB stabilising loop and the jelly pot can supply plenty of of that. Many, many years ago a BRC 950 Mk2 came in for repair, evidently the last repairer had given up trying to fix the set. Someone had wrote inside the cabinet "died in 1968 of too much EHT". Of course the fault was in the stabilising circuit and it was a simple matter of replacing all the components in the LTB, the VDR width control and the feedback capacitor.
Geordie McBoyne.
