Amiga 500,500+,2000,3000 drive selector switch

How does it work On the Amiga 500,500+,2000,3000 you can’t boot from the external (DF1) drive by default, so you need a switch so the external (DF1) drive will act as DF0: Switch position 1 (default) Internal Drive is DF0: External Drive is DF1: Switch position 2 External Drive will be acting as DF0: Internal […]

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Compact Flash LED not working

Some Compact Flash (CF) to IDE adaptors fail to light up the drive activity LED, I was wondering why… I took a board and removed some components and did some measurements, and I  discovered that the BOTH base pins of the NPN transistors are connected to ground. Huh?! That means that the transistors won’t switch […]

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CDTV CDROM no data discs repair

This time a Commodore CDTV arrived on my workbench with the following symptoms: Plays audio cd fine Does not load CDROM (CDTV) discs After checking that the CD mechanism worked fine using an audio CD I tested with several CDTV discs both original and recordables. During loading the CD spins up OK and there is […]

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Amiga 1200 Rev 1D1 Noise on video signal (LM385)

  I’ve seen some 1200 Rev. 1D.1 boards missing the D215 (LM385), this will result in a higher voltage on the DAC VREF signal (U30) and noise will shown when you dragging workbench windows, accessing HD or floppy, etc.. When you place a LM385 then the picture will be much better. If the LM385 is broke, […]

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