Commodore 64 Assy No. 250425 Rev. A motherboard and case

Assy 250425 Rev. A

This is a Version B motherboard produced from 1984. Numerous chips surrounding the VIC-II (MOS6569) graphics chip have been replaced by a single clock generator IC (MOS 8701). The locations of the SID (MOS 6581) and the PLA (MOS 906114) have been swapped with respect to Version A-CR.

The inside of the machine:IMG_3088

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All electrolytic capacitors and voltage regulators have been exchanged for new ones as described in the C64 Capacitor Mod.

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The CPU, the VIC-II, the PLA and the SID chips all have heatsinks attached to keep them running cool. Heatsinks and thermal tape have been bought from the Retroleum.co.uk spares shop.

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Capacitor C38 (51 pF) has been replaced by a 4.7 nF one to make the RESTORE key work like all the other keys as described in the C64 RESTORE Key Mod.

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The outside of the machine:

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