Grundig KS 715GB Radiogram

[Yorkie]

Thanks for the advice Rob, would it be worth changing C43 while I am at it.
I take it the replacement rectifier will work, just that it is a bit of overkill?

If it's a simple task to replace C43, why not? Like C46 & 47, it will have 100Hz on it from the bridge rectifier. However, it might be worth cheking the ESR and capacitance to see if they seem to be problematical or it's just random replacement based on supposition rather than diagnosis. That said, we know that electrolytic caps in transistoried equipment are physically small and over the years will dry out and develop a high ESR. That will often degrade the performance, but not necessarily stop equipment from working. If you do replace C43/46/47 and the hum persists, at least they're no longer suspect and the hum problem lies elsewhere.

As to the bridge rectifier, yes, it will work, but as you say Paul, it's overkill, as its rating is more than twenty times the WV and twenty times the current (given that the fuse rating is 315 mA).

Generally, the markings on high current bridge rectifiers show the current and voltage ratings, so for example, a 1502 is 15 Amps at 200 Voits, 2502 is 25A at 200V, 2506 is 25A at 600V and so on. Markings are a bit more obscure for lower volatge and current ratings.

If you've got a Maplin nearby, a KBPC1005 (60V 2A) Stock No AQ98G will only set you back 69p and might be a better bet. (But if it 'aint broke, don't fix it!).

Good luck with the restoration. (Very high component count, and lots of 'three-legged fuses'!)