Odd Software for Odd Jobs

BBC Model B

The grandaddy of most smartphones and anything else running on an ARM-designed processor?

I think I may have a few too many of them though.

The one on top is a Master Compact which isn't currently working. It's a pretty nice keyboard so I had a thought of maybe converting it to a USB/PS2 keyboard … maybe for a Raspberry Pi? Anyway …

2016-03-12 14.24.14

I think I'll try to whittle my collection down and sell some on eBay. Starting with an Issue 4 first - it's currently not functional - power supply seems okay (but I'm going to refurbish the X2 capacitors anyway). On startup, it maintains the low beep and nothing appears on the screen. So am going to troubleshoot that after working on the power supply.

I've installed a modern 1770 floppy drive controller replacement daughterboard from RetroClinic and an IDE-to-CF card interface that connects to the 1MHz bus.

2016-03-12 14.41.55

2016-03-12 14.43.06

The video processor chip gets pretty hot in this Issue 4 board so I've re-applied fresh heatsink plaster and re-seated the heatsink.

2016-03-12 14.42.19

I've previously removed the motherboard to install the IDE-CF card interface and so have removed the BNC connector used for the composite video out. The first thing I did was solder in a header on the S39 link to enable the chrominance signal on the composite output (so it'll be colour rather than B&W). The holes on the circuit board were already full of solder so I figured the quickest/cleanest way to clear them was to drill the solder out with a 1mm drill bit and hand drill. Simple!

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I've also replaced the BNC connector with an RCA socket (so I don't need to use a BNC-plug-to-RCA-socket adaptor) … and (cleverly?) soldered in a pin rather than just soldering the wire onto the motherboard - I figured if I needed to remove the motherboard again, I can just "unplug" the composite output wire than having to break it again.

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