01-19-2008, 02:21 PM
Hi Chris,
On some sets there is a common B- line. or as some say, a 'floating ground" one that is not in contact with the chassis.
You can see that some caps have the ground symbol, that would be the chassis. If you follow pin 7 I believe from your 50A5, there will be a 220 Ohm resistor (R204) paralleled with a 25uf cap. The negative end on that cap (and the resistor) is your B-.
There are other points you can trace this line going to, such as the other end of the 120 Ohm resistor onpin 2 of your 6BJ6, (R307) .
Some manufacturers use a chassis symbol that looks like a rake, and their B- is the common ground symbol.
Someone can correct me if I am wrong on this particular set , but I just had to deal with a isolated B- on an RCA I recapped last week.
Take care,
Gary.
On some sets there is a common B- line. or as some say, a 'floating ground" one that is not in contact with the chassis.
You can see that some caps have the ground symbol, that would be the chassis. If you follow pin 7 I believe from your 50A5, there will be a 220 Ohm resistor (R204) paralleled with a 25uf cap. The negative end on that cap (and the resistor) is your B-.
There are other points you can trace this line going to, such as the other end of the 120 Ohm resistor onpin 2 of your 6BJ6, (R307) .
Some manufacturers use a chassis symbol that looks like a rake, and their B- is the common ground symbol.
Someone can correct me if I am wrong on this particular set , but I just had to deal with a isolated B- on an RCA I recapped last week.
Take care,
Gary.
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