Dear Mr Pandu Rajan,
Thank you very much for your post. I am Prabhat Chandra who spoke to you from Dehradun. Miroflex is my pen name on this site. I had posted my requirement here in the hope that I might be lucky enough to find the speakers with some member here.
Regards.
Dear Sir
This is going to be a longish post thus I beg your indulgence.
It is doubtful if any of the commercial repair people mentioned in this thread can restore a BX998A. The electrical circuit and it parts are very challenging. More than that the mechanicals are extremely complicated. Philips radio were very intricate but this one was over the top even for them. As an analogy functions of this radio will require a microprocessor device today. Philips did this with a maze of electro-mechanical devices.
Some years ago I was given (or what was left of it) a BX998A. The previous owners had left it unused it in a outdoor shed for several years. As a result the outer cabinet was destroyed by seepage/worms and dangerous critters were crawling all over it. I didn't dare take it indoors and left it a corner of the garden. After several days of insecticide treatment I was able to investigate and it dawned on me that fixing such a complex thing was beyond my scope. It would have required the perseverance and skills of our respected Shri Pandu Rajan ji to attempt any such repairs.
But despite such abuse the chassis and body parts were in fair condition. There was no corrosion, the golden lettering were still perfect, the golden liner on the knobs were still shining. Just goes to show the quality.
It stayed outside for a couple of years then one day the remains were simply thrown over of the boundary wall. My wife felt that such broken wrecks bring ill luck to the household. I thought of recovering some parts but in the end saw the futility of it.
Your radio with high impedance speakers was part of a quirky Philips design philosophy. It seems they were always tinkering with the output stage of their radios. Even a simple SE output stage transformer would have multiple primary and secondary wiring. The wiring were variously used for power supply smoothing, feedback network, tone/volume control, etc. Thus it is very difficult to find a standard replacement in case the original transformer is damaged.
So why they were doing this? I can only guess they were trying to optimize the manufacturing cost. I think by mid 50s they had the PL/UL series valves and combined with OPT-less design they could have a radio without a single transformer in it. But in plush Bi-Ampli /Reverbo series of radios (such as BX998A) cost doesn't seem to be a limiting factor. They could have well gone for conventional push pull output stage which other high end models such as Pye Cambridge (Our esteemed FM Shri Rajiv from Chennai had one) used. Thus I can't conclusive think that cost saving was the only factor. It is just my guess work.
Incidentally, I have seen an advertisement for BX998A on Readers Digest of 1961 which mentioned the price as only Rs 750. As a comparison my father who was an Engineer earned Rs 300/pm those days.
It is good that Shri Pandu Rajan has located a high impendence driver in Holland. From my experience you can find one in India also if you ask around old repair shops. Trust me on this. There were plenty of these radio sold in India.
In lieu of the said loudspeaker another option could be using a 30 Watt Line Matching PA transformer. The primary will probably reflect an impedance of 600 ~ 800 ohm from the 8 ohm tap. It is just a thought thus kindly don't take my words on it. However if left with no option I will personally explore this further. I think the bandwidth will be quite wide for the application.
Whatever is the case please make all reasonable efforts to restore this radio. I have seen these models in action and you can't possibly get a better valve radio than this.
Warm regards
aks
