Preamp X08-1720-10
C1/C2 120p > 120p C0G - (Did not have these on hand, but recommed to replace)
C3/C4 100p > 100p AVX SR21 C0G
C5/C6 10uf 25V LL Orange 6mm > 10uf 50V RFS 8mm
(Caution: PCB has wrong polarity for C5/C6)
C7/C8 100uf 10V 8mm > 100uf 25V FG 8mm
C13/C14 .012uf > .012uf 100V Arcotronics
C17/C18 2.2uf 50V 5mm > 2.2uf 50V MKS2
C22 1uf 50V LL Orange 5mm > 1uf 50V MKS2
C25 4.7uf 25V 5mm > 4.7uf 50V MKS2
C27/C28 47uf 25V 10mm > 47uf 63V Nichicon KL 10mm
(Caution: PCB has wrong polarity for C27/C28)
C29/C30 47uf 25V 10mm > 47uf 50V Nichicon KZ 10mm
C31/C32 220uf 25V 12.5mm > 330uf 63V Nichicon PM 12.5mm
R1/R2 220K 0.35W > 220K 0.5W metal film Yageo
R3/R4 100 ohm 0.25W > 100 ohm 0.5W metal film Yageo
R15/R16 330 ohm 0.25W > 330 ohm 0.5W metal film Yageo
The preamp board. The phono amp consists of two
HA1457 low noise devices and a third HA1457 that operates the microphone amp.
Closeup view of the phono amp.
The input selector and microphone amp.
In order to reach the components for R&R on the preamp three screws along the bottom of the rear panel need removed, the knob of the mic mixer, and the nut the holds the input selector switch. Then the rear panel can be tilted back for full access.
The completed component changes of the preamp board.
The left side of the preamp board recapped. C3/C4 100pf were given C0G dielectric type replacements. I would have replaced C1/C2 120 pf, but I didn't have parts on hand. The original carbon film resistors R1 to R4 were replaced with 1% tolerance metal film of the same value.
Right side of the preamp board recapped along with the addition of metal film resistors at R15/R16.
The input selector switch removed from the preamp board for cleaning. Portions of the contacts are badly tarnished.
The input selector switch after a thorough cleaning. Again, I used Brasso to remove the tarnish, followed by a hosing down of contact cleaner, and finally an application of DeOxit Gold.