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Chindit · 16th Feb 2018, 10:40 am

Regarding LT voltage, the DK96 frequency changer will start to drop out and stop oscillating at progressively higher Lt voltages as it ages. A good one should still function down to around 1.1 volts, but a tired one may well stop functioning when the LT drops to 1.3 volts or so.
Again, be very careful to avoid over volt-ing these battery valves - A pair of new alkaline C or D-cells will put out close to 1.6 volts, even on load, when first installed in a set. Consequently, I've taken to incorporating a 1.2 ohm resistor in the LT+ feed from battery to socket in all my battery portables.
The main problem I've found with the LT circuits on these sets is poor contacts within the McMurdo B7G valve holders leading to seriously reduced voltage across pins 1 and 7 of the valve itself. A clean up of the lid-operated LT switch (where fitted) and individual valve pins along with changing any broken contact elements in the valve holders will help.
Colin.

16th Feb 2018, 10:40 am	#24
Chindit Tetrode Join Date: Feb 2011 Location: Bishop Auckland, County Durham, UK. Posts: 97	Re: AD35/B126 Batteries Regarding LT voltage, the DK96 frequency changer will start to drop out and stop oscillating at progressively higher Lt voltages as it ages. A good one should still function down to around 1.1 volts, but a tired one may well stop functioning when the LT drops to 1.3 volts or so. Again, be very careful to avoid over volt-ing these battery valves - A pair of new alkaline C or D-cells will put out close to 1.6 volts, even on load, when first installed in a set. Consequently, I've taken to incorporating a 1.2 ohm resistor in the LT+ feed from battery to socket in all my battery portables. The main problem I've found with the LT circuits on these sets is poor contacts within the McMurdo B7G valve holders leading to seriously reduced voltage across pins 1 and 7 of the valve itself. A clean up of the lid-operated LT switch (where fitted) and individual valve pins along with changing any broken contact elements in the valve holders will help. Colin.