Partial restoration of a Marantz 2270

cortico
cortico Posts: 587
edited March 2018 in DIY, Mods & Tweaks
This time sharing a partial restoration of a 2270. This old amps totality deserve being salvaged. Someone was in there before and did a few silly things as replacing just one of the filter caps, the unit was having issues that were resolved after project was complete.

The planed scope was done as follows:

Power supply
-Replace and upgrade mail filter caps, total capacitance was increased.
-Replace all electrolytic capacitors.
-Replace speaker protection relay, this has fixed right channel intermittence.
-Upgrade diodes with fast soft recovery diodes, this reduces background noise.
Used a Omron relay, Nichicon KG main filter and Elna Silmic II caps

Preamp
-Replace all electrolytic capacitors.
Used Elna Silmic II and Panasonic ECQ films, 3.3uf and lower can take film.

Power amp
-Replace all electrolytic and tantalum capacitors.

Phono Board
-Replaced 2SC458 transistors with KSC1845, originals have a tendency to become leaky and add noise.
-Replace all electrolytic and tantalum capacitors.
-Upgraded existing diodes

-New vellum paper
-New incandescent bulbs
-New power switch and safety cap

Before:
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After:
Top
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Bottom
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Power supply:
Before:
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After
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These are huge:
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Pre amp, access was somewhat difficult:
Before:

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After:
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Power amp, the access was also not easy:
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Phono amp
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Some of the part replaced:
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Post edited by cortico on

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