Repair/Restoration: Commodore Plus/4

[@Retro4u]

Hi. Nice video just picked one up myself to do a video on.

[@RetroKrazy]

Nice! I was lucky I think as all chips behaved as they should. Fingers crossed you get a good one too!

[@gherosh]

Nice restoration! 👍

[@RetroKrazy]

Thanks :-) There will be a small revisit as there are other things I want to cover and check the dataset port so more to come!

[@ralfs_welt]

How can the plus/4 run so much faster than the C64? The processor in the plus/4 is a 7501, the processor in the C64 is a 6510. Both are based on the 6502-CPU. The CPU in the plus/4 is clocked with 885kHz or 1,76 MHz, depending on what the TED-Chip is actually doing. The average speed is at about 1 MHz, the C64 runs at 985 MHz (PAL-System).

[@RetroKrazy]

I know, it doesn't seem to make sense however: It's about 12% slower while displaying graphics and 78% faster when not. This means a PAL Plus/4 has about 40% more CPU cycles than a C64. The C64 CPU also does waitstates while the VIC reads graphic data from memory. You therefore lose up to 66% of all memory cycles upon every eigth line displaying data. Please note I am NOT a computer guru and gleaned all this off the internet myself. Some even say that the Plus/4, in certain circumstances, can operate faster than a 2Mhz C128! At the end of the day, it's still a neat little machine, if quirky as hell :D

[@JamesPotts]

It was released as a "business" machine, but it was designed to compete at the VIC20 and Sinclair price range.

[@RetroKrazy]

Yes, just a shame that the built in 'Business' applications were so bad! Can't disagree on the price though. shame it didn't take off more tbh.

[@alessandrameazell8397]

Promo*SM

[@RetroKrazy]

Bot reply maybe? Or trying to sell something I haven't endorsed? if so, NAUGHTY!