All that it is necessary to do to the crossover you are refurbishing is to replace the ageing ELCAP bipolar electrolytic capacitors with modern equivalents.
For example, you may replace a 25 uF ELCAP with a modern standard value of 22 uF as the tolerance of ELCAPS wasn't tight in the first place.
If you are fussy, wire a 3.0 uF in parallel with a 22 uF to give 25 uF. https://wilmslowaudio.co.uk/mundorf-electrolytic-ecap-capacitors
The inductors and resistors can be left as is which will help ensure the originally intended sound quality.
For example, you may replace a 25 uF ELCAP with a modern standard value of 22 uF as the tolerance of ELCAPS wasn't tight in the first place.
If you are fussy, wire a 3.0 uF in parallel with a 22 uF to give 25 uF. https://wilmslowaudio.co.uk/mundorf-electrolytic-ecap-capacitors
The inductors and resistors can be left as is which will help ensure the originally intended sound quality.
I found this image and we can make out the L values.
2 X 0.2mh
1x 2mh
1 x 2.5mh
25, 25, 4.7uf caps
2 X 0.2mh
1x 2mh
1 x 2.5mh
25, 25, 4.7uf caps
Thanks all - mine have a 6microFarad cap instead of the 4.7 in jimk's picture but they look original. I'd still be interested to see the circuit diagram if anyone has one.
Draw it out - there's hardly anything to it - piece of paper and a pencil, job done.
I'm with Nigel.
Since you have physical access to the front and rear of the crossover board you are in a good position to try roughing out the circuit diagram for yourself.
As a guide, the layout will be similar to that of the attached Wharfedale Linton 3XP crossover (courtesy of member system7).
(From top to bottom: tweeter; midrange; woofer.)
Since you have physical access to the front and rear of the crossover board you are in a good position to try roughing out the circuit diagram for yourself.
As a guide, the layout will be similar to that of the attached Wharfedale Linton 3XP crossover (courtesy of member system7).
(From top to bottom: tweeter; midrange; woofer.)
Attachments
Thanks boys ... you are of course right but following the printed circuit as it squiggles around like a tray of snakes and switching my attention between the components on the front and the blobs of solder on the back makes me go cross-eyed and dizzy ;-)
You can imagine how tricky it would be to do it from photographs! 😀
Simply replace the capacitors - the audible difference may astound you.
Simply replace the capacitors - the audible difference may astound you.
I have replaced the capacitors with ALCAP equivalents - same values but rated at 100V instead of 50V - and the speakers now sound as good as new - thanks to all