UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Philips 663A combined radio/television 1948

Pieter H · 13th Aug 2021, 2:04 pm

Hi Matt, all,

apologies for joining this discussion rather late.
Beautiful 663, the first time I see one "life".
The development of this chassis in the context of the total Philips TV development I have described here.
So some additions to earlier points raised:

The CRT used by the simpler (non-radio) versions of the family (463, 563, 383) used the MW22-7, the 663A used originally the MW31-7 but this was quickly upgraded in production to the MW31-14. Impossible to say which version was originally used in this specific set, but the MW31-16 is clearly a later upgrade.
The ECH35 is in view of later developments of course not a perfect RF mixer-oscillator. However, we need to see this in the context of developments then. The predecessors from 1939 (the 2400 family) used the ECH3 as TV MO, the Philips SX861 from 1946 used the ECH21. As described in my history, it seems that the ECH35 was a local Mullard favourite, since the more modern ECH21 should have been better. The next generation Mullard MT521/Philips 520 used a CCH35 as oscillator and EF50 as mixer but for the next 3 years a single self-oscillating EF/UF42 was used throughout Philips.

I am not a repair expert, but nevertheless some stupid questions/suggestions:
- given your problems with audio: because the TV and radio share the entire audio chain except for the RF pre-amplifier, did you check the audio chain for radio reception? That should say something on the ECH35 functioning too.
- are you using the correct IF frequencies? In the years 1946-1950 every Philips/Mullard chassis had different values! This one should be 13,2MHz VIF, 9,7MHz SIF.

I look forward to some nice pictures of the fully restored set, eager to add a few to my history site!

Cheers, Pieter

13th Aug 2021, 2:04 pm	#40
Pieter H Tetrode Join Date: Sep 2017 Location: Waalre, Netherlands Posts: 67	Re: Philips 663A combined radio/television 1948 Hi Matt, all, apologies for joining this discussion rather late. Beautiful 663, the first time I see one "life". The development of this chassis in the context of the total Philips TV development I have described here. So some additions to earlier points raised: The CRT used by the simpler (non-radio) versions of the family (463, 563, 383) used the MW22-7, the 663A used originally the MW31-7 but this was quickly upgraded in production to the MW31-14. Impossible to say which version was originally used in this specific set, but the MW31-16 is clearly a later upgrade. The ECH35 is in view of later developments of course not a perfect RF mixer-oscillator. However, we need to see this in the context of developments then. The predecessors from 1939 (the 2400 family) used the ECH3 as TV MO, the Philips SX861 from 1946 used the ECH21. As described in my history, it seems that the ECH35 was a local Mullard favourite, since the more modern ECH21 should have been better. The next generation Mullard MT521/Philips 520 used a CCH35 as oscillator and EF50 as mixer but for the next 3 years a single self-oscillating EF/UF42 was used throughout Philips. I am not a repair expert, but nevertheless some stupid questions/suggestions: - given your problems with audio: because the TV and radio share the entire audio chain except for the RF pre-amplifier, did you check the audio chain for radio reception? That should say something on the ECH35 functioning too. - are you using the correct IF frequencies? In the years 1946-1950 every Philips/Mullard chassis had different values! This one should be 13,2MHz VIF, 9,7MHz SIF. I look forward to some nice pictures of the fully restored set, eager to add a few to my history site! Cheers, Pieter