Mullard radio MAS231 (Algemeen)

door Pandu Rajan , 09.04.2018, 09:32 (2421 dagen geleden)

Dear friends
I have completed the restoration of the radio set Mullard MAS231. The photos shows the condition of the set before and after restoration. It is one of the most difficult sets I have come across during restoration. Lots of work was done to restore the set and I have given the jobs done in detail. Also I have attaching many photos which will highlight the progress of the restoration of the set. The details of the restoration are as follows:

1. The set was received in a very bad condition. It was first thoroughly cleaned before starting the restoration.
2. The chasis was thoroughly cleaned.
3. The band switch gear assembly was dismantled cleaned and lubricated and fitted back.
4. The bottom of the audio amplifier around the valve B5 & B6 was badly carbonized may be due to some short circuit earlier. Thoroughly cleaned the chasis of the audio amplifier.
5. Changed all the black capacitors.
6. Removed all the wrong connections done and the wiring done as per the schematic including the wiring of R44. Removed all the defective wiring. Redone with fresh wires.
7. Replaced R42,R44,R34,R43 resistances.
8. Replace the screened cable around the volume control and P.U./Radio switch.
9. Then started the work on the top of the chasis.
10. Replaced the main transformer with a new one with original specification.
11. Replaced the filament transformer ( for the dial lamp and filament of EM34) with a new one as the same was missing.
12. Replaced both the filter capacitors C1 and C2 and rewired the same including R36 and C138 as per the schematic.
13. Replaced all the wires of EM34.
14. Replaced R89 and connected R63 which was missing.
15. Checked the O/P , Interphase transformer and the IF transformers and found them O.K.
16. Completed the top restoration of the chasis.
17. Painted the chasis with grey paint similar to the original.
18. Painted the dial cord mounting plate with silver paint.
19. Changed the cloth of the speaker baffle board and the wooden board behind the dial.
20. Replaced all the four springs of the band indication cord and put new cord.
21. Used the original steel cord for the pointer as the same was in good condition and fixed the pointer properly.
22. Changed the wiring of the dial lamps.
23. Repaired the speaker with new cone , coil and spider and provide a new dust cover.
24. The only modification done was providing fuses in the circuit for the protection of the transformer.

Regards
P.Rajan