Marantz 2330 Euro Restoration
Heres another great 2330 that came in for just a basic restoration. This particular unit is a European variant which basically means it lacks the P600 Dolby integration along with the voltage conversion.
As far as the 2300 I love to work on these units, the modular molex connections make for a fairly quick tear-down. The 2325 and 2330 are similar in the fact that the regulated supply (P800 is the same in both units, on occasion I have seen different relays though such as a my4 vs a dual throw.
P800 Power Supply
The design of the relay circuit is interesting to say the least, one caveat is that the thermal breakers attached to the P700 assemblies are actually in series with the coils at J814/815 via the collectors of H806/807.
All the caps were replaced with long life, high temp Panasonic FR/FC's, the diodes and zeners I added are a little more robust with a ultra fast 4005 diode. Because of the extent of the glue, most BJT's and resistors along with the film were replaced as well, in the factory they really made a mess of this assembly. The common rectifiers were replaced with TO-220 packaged MUR1620 series and a new Omron MY2 relay added. the sinked transistors had the mica replaced with new compound added as well.
The lyrics here were replaced with Elna Silmics and an axial packaged TVX Nichicon, as I usually do with smaller capacitance values, WIMA MKS2 were used. The smooth red films Im not a fan of were replaced with Panasonic polypropylene ECW films. As a precursor the potentially problematic 405/406 transistors were replaced with ksc1845s and the rest of the glass diodes replaced with 4148's in series or singled.
P700 Power Amplifier Assemblies
Per my usual all the lower value capacitance lyrics were replaced with Wima MKS2 and a Panasonic ECW PP films and Elna Silmic II's for the rest. I did use a nice MKP PP to replaced the film at 706 with excellent results I thought. I've tried a few other PP's in this application but I keep returning to MKP's. The differentials were replaced with new thermal compound sandwiched and heat-shrinked together. I really like these more robust heavy duty potentiometers for the dc and Bias personally. I think they beat the modern smaller Bourns unless they tend to drift or don't stabilize during adjustments I keep these type.
PE01 Tone / Pre-Amp
All the BJT's here tend to be okay, but as a precusor while I was in I like to update them to some more reliable, in this case matched 992'1845's BJT's. All the tantalums were replaced with either Silmics or WIMA MKS2's. CE37/38 are a pair of bi-polar, I used some nice MUSE but any film would be great as well. The small gray films at CE05/06 were replaced with nice Panasonic ECW polypropylenes, I would like to try the MKP's here sometime. I've tried Mundorfs in the same location in a 2325, but it wasn't anything to write home about.
PH01 Buffer had the lyrics replaced with all Panasonic FR/FCs. And new 18K 100V Nichicon main filter capacitors were added. These were an exact drop in with the Z-bracket lining up perfect. A new switch with a Vishay X1Y2 and the unit was buttoned up. Should add, probably from removing the euro jack, but a power cord had been spliced with tape. Needless to say a new power cord and tap were added for safety reasons. Like the 2325, P700 as easy access BIAS test points added which makes it straight forward.
Again, the 2300 class has to be my favorite variant to work on and they sound phenomenal, plenty of headroom, great extension and aesthetics to match.