Change capacitors
Quad FM4






M12615 ISSU 5
Symptoms: the transformer heats up abnormally! On this device, the change of electrolytic capacitors is done without difficulty, because they are very well marked on the back of the printed circuit, near the welds the polarity of the component is written in a very legible way. A total of 12 capacitors and a D7812 regulator will be changed for this restoration, the verdict is final, the device no longer heats up and the illumination of the display segments is much brighter. Attention need to change the RIFA brand capacitor (N1), it is also advisable to change it rather than removing it, it is an effective component, which will prevent you from certain unpleasant noises in your speakers when you turn off your device. The bipolar capacitor c63 is also to be changed, its value is not very common, but one finds in particular on EBAY.
DIY - Change capacitors
Preferably choose capacitors (105°c).



The capacitors removed.

the red dots are the new capacitors.


RIFA Capacitor PME271M Series / MP Type (Metallized Paper Film Capacitor) Class X2: for direct use on 230VAC mains (IEC 60384-14)
List of new capacitors.
Names | Capa µf | Volts | Temp (°c) |
C4 | 1000 | 40 | 85 |
C5 | 1000 | 40 | 85 |
C6 | 220 | 25 | 105 |
C11 | 100 | 25 | 105 |
C12 | 100 | 25 | 105 |
C30 | 2.2 | 63 | 85 |
C34 | 100 | 25 | 105 |
C37 | 2.2 | 63 | 85 |
C56 | 22 | 25 | 105 |
C57 | 470 | 25 | 105 |
C63 BIP | 0.47 | 100 | 105 |
N1 RIFA | 0.047 + 100R | 275 |