Hi,
About a year ago, I had very sloppy sound from my BM1600M (basically the same as the 1400M).
I replaced all the Electrolytic caps, with Vishay BCE (the descendant of the original Philips) units - they even look almost identical with the blue colour, and the loudspeaker volume slider caps with Panasonic ECG Metallized Propylene caps (labeled WF185J - 250V).
To replace these, you need to remove the IF box - I haven't figured out how to upload my pictures to the forum, but if you send me your email address, I'll get them to you!.
The sound (2x15W) is fabulous.
You can get all these caps from Digikey in the USA.
Regards
M Yachad
Learn from the mistakes of others - you'll not live long enough to make them all yourself!