Philips main transformer for BX696A (Algemeen)

door Pandu Rajan , 24.05.2021, 06:46 (1279 dagen geleden) @ Maurice

Dear Mr. Maurice
1. The main transformer of BX696A has a code A3.141.71. Somebody has replaced with one which gives higher secondary voltage for the same primary voltage. The replaced transformer is also Philips but of some other set.

2. The code no of the transformer for BX695A is A3.141.53. I think the voltages of both the transformers are same but A3.141.71 has a higher current rating as the resistance of the winding is less.

3.The service manual of BX696A brings out only the changes that have been made in the set BX695A and clearly mentions that for other works the service manual of BX695A has to be referred.

4. 4V and 6.3V windings are O.K. and only the higher voltage in the secondary. Otherwise the transformer in general is O.K.

5. The anode voltage on the anodes of EL41 valve is 280V.

6. Why I came to the conclusion that the transformer has been replaced is when I started the restoration I noticed that the transformer had been mounted 180 degree shifted i.e. the front was at the back and the back was in the front so all the connections redone. All the wires of the voltage selector tap was cut.

7. The same transformer A3.141.71) has been used in BX704A and the voltage at C1 has been given as 265V and at C2 it is 230V

8. I made a simple experiment. With a voltage stabiliser I applied such a voltage so that
at C1 I was able to get 265V. At C2 I was getting 240V and the incoming voltage for this
setting was 200V. The anode voltages at AZ1 came to 244-0-244V.

Best Regards
P.Rajan