07-27-2008, 09:02 PM
Brian,
On the 1204 chassis, the grid of the eye tube is actually tied directly to the avc line. That is a very high resistance circuit and any metering at that point would upset the avc. On the 5905 chassis, the eye tube grid is only isolated from the main avc line by R3, a 100K resistor. That is not enough. I'm afraid metering at that point would upset the avc also. I am not an expert and I'm sure there are some sets where metering at the grid of the eye tube would not upset the avc and therefore be a valid technique. As exray suggested earlier, you might try metering through a 5 or 10 meg resistor to the grid of the eye tube. That may help. Or, you could just use the scope and be done with it.
Ed
On the 1204 chassis, the grid of the eye tube is actually tied directly to the avc line. That is a very high resistance circuit and any metering at that point would upset the avc. On the 5905 chassis, the eye tube grid is only isolated from the main avc line by R3, a 100K resistor. That is not enough. I'm afraid metering at that point would upset the avc also. I am not an expert and I'm sure there are some sets where metering at the grid of the eye tube would not upset the avc and therefore be a valid technique. As exray suggested earlier, you might try metering through a 5 or 10 meg resistor to the grid of the eye tube. That may help. Or, you could just use the scope and be done with it.
Ed
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