Brom onderdrukking in Philips radio's (Algemeen)

door Pandu Rajan , 15.07.2016, 05:54 (3055 dagen geleden)

Dear Members

With reference to the thread Remarkable Modification BX520A dated 1.7.16 I have some queries to ask which are as follows:

1. Is it necessary that in all cases where a +ve voltage is applied to one end of to the filament of EBC41/ECH21 for reduction of HUM, one end of the filament winding of the main transformer is not Grounded?

2. In the set BX765X one end of filament of the valve ECH21 ( B4) is connected to the cathode through a resistance R109. Is this also going to serve the same purpose as in 1 above?

3. In the set BX716X the filament winding of the main transformer for the valve B3 only (EBC41) is given through a choke S51 and the filament itself is shunted by variable resistance R64?

4. In the set BX806X one end of the filament of the valve B6 only i.e. EF40 is grounded. Why?

5. What is the amount of + voltage given to the filament for HUM reduction?

Regards

P.Rajan