Commodore 64 External Power Supply, Part No. 902503-02
I have taken a circuit diagram by William Levak from Bo Zimmerman's website and made some corrections and changes. The drawing at Zimmer's shows a PNP transistor labeled "SK3052P" which I believe is in error and should've been a 3052P, which is a +5 VDC, 2A voltage regulator. NTE 1934 is an equivalent part. Moreover, I believe the original resistor is 30 ohms, not 300 ohms.
When repairing, I used a 3W resistor instead of the original half-Watt. The original diodes were 1N5400 (50 V), but I used 1N5408 which can withstand much higher voltages (1 kV) (see 1N540X datasheet to compare).
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P. David Buchan email@example.com
December 22, 2016