Commodore 64C: Difference between revisions
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The '''Commodore 64C''' (often shortened to '''C-64C''' or simply '''64C''') is the cost-reduced, slim-line redesign of the original [[Commodore 64|Commodore 64 “bread-bin”]]. Introduced during 1986, the C64C kept full software and peripheral compatibility while lowering manufacturing cost, power consumption and heat output. Roughly four million units of the new style were produced, helping extend the C64 family’s commercial life to 12 years. | The '''Commodore 64C''' (often shortened to '''C-64C''' or simply '''64C''') is the cost-reduced, slim-line redesign of the original [[Commodore 64|Commodore 64 “bread-bin”]]. Introduced during 1986, the C64C kept full software and peripheral compatibility while lowering manufacturing cost, power consumption and heat output. Roughly four million units of the new style were produced, helping extend the C64 family’s commercial life to 12 years. | ||
== | == Architecture and Processor == | ||
* '''CPU : MOS 8500''' — an HMOS-II shrink of the 6510, fabricated on 2 µm silicon and running from a single +5 V rail. | * '''CPU : MOS 8500''' — an HMOS-II shrink of the 6510, fabricated on 2 µm silicon and running from a single +5 V rail. | ||
* Clock rates remain '''≈1 MHz NTSC (1.023 MHz)''' and '''≈0.985 MHz PAL'''; timing is generated by the 8701 IC (short boards) or discrete VCO (early C64C boards). | * Clock rates remain '''≈1 MHz NTSC (1.023 MHz)''' and '''≈0.985 MHz PAL'''; timing is generated by the 8701 IC (short boards) or discrete VCO (early C64C boards). | ||
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* Slightly faster rise/fall times on the address bus, easing DRAM timing margins. | * Slightly faster rise/fall times on the address bus, easing DRAM timing margins. | ||
== | == Memory and ROM Map == | ||
{| class="wikitable" | {| class="wikitable" | ||
! Region !! Size !! Device !! Notes | ! Region !! Size !! Device !! Notes | ||
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* '''Character ROM''' (U3) unchanged (4 KB 2332 mask), but later boards use a 27C64 EPROM-compatible pin-out. | * '''Character ROM''' (U3) unchanged (4 KB 2332 mask), but later boards use a 27C64 EPROM-compatible pin-out. | ||
== | == Display and Graphics == | ||
Graphics are provided by a new HMOS VIC-II family: | Graphics are provided by a new HMOS VIC-II family: | ||
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* Raster interrupts driven by the VIC-II still allow “raster bars”, split-screen scrolling and other demo effects made famous on the original C64. | * Raster interrupts driven by the VIC-II still allow “raster bars”, split-screen scrolling and other demo effects made famous on the original C64. | ||
== | == Sound – SID 8580 R5 == | ||
The 64C introduced the '''MOS 8580''' HMOS SID: | The 64C introduced the '''MOS 8580''' HMOS SID: | ||
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* Paddle inputs now require 100 kΩ potentiometers (versus 470 kΩ on 6581). | * Paddle inputs now require 100 kΩ potentiometers (versus 470 kΩ on 6581). | ||
== | == Input/Output and Expansion == | ||
All ports are retained: | All ports are retained: | ||
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* '''Composite video + separated chroma/luma''' on the 8-pin A/V DIN (RF modulator still present for TV use). | * '''Composite video + separated chroma/luma''' on the 8-pin A/V DIN (RF modulator still present for TV use). | ||
== | == Cost-Reduction Motherboard Revisions == | ||
{| class="wikitable" | {| class="wikitable" | ||
! Assy No. !! Nick-name !! Key changes !! Used chips !! Used in | ! Assy No. !! Nick-name !! Key changes !! Used chips !! Used in | ||
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|} | |} | ||
The Super-PLA runs | The Super-PLA runs ''cool'' and is considered highly reliable compared with the original ceramic PLA. | ||
== | == Maintenance & Common Faults == | ||
* '''PSU failure''' – original “brick” still prone to over-voltage; modern protected PSUs (C64 Saver, new-build bricks) are strongly recommended. | * '''PSU failure''' – original “brick” still prone to over-voltage; modern protected PSUs (C64 Saver, new-build bricks) are strongly recommended. | ||
* '''Yellowed case''' – C64C plastics are ABS and will photo-degrade; [[Retrobrite|retrobright]] procedures restore colour but weaken plastic if over-done. | * '''Yellowed case''' – C64C plastics are ABS and will photo-degrade; [[Retrobrite|retrobright]] procedures restore colour but weaken plastic if over-done. | ||
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* '''RAM & colour-RAM''' rarely fail on the short board; the next most common faults are the 8701 and the RF modulator solder joints. | * '''RAM & colour-RAM''' rarely fail on the short board; the next most common faults are the 8701 and the RF modulator solder joints. | ||
== | == Troubleshooting Highlights (Differences vs. Bread-bin)== | ||
{| class="wikitable" | {| class="wikitable" | ||
! Symptom !! C64C-specific suspect !! Notes | ! Symptom !! C64C-specific suspect !! Notes | ||
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|} | |} | ||
For | For fault-finding refer to the [[Commodore 64C Troubleshooting Guide]] (companion page). | ||
== | == Technical Manuals == | ||
* ‘‘Commodore 64C/C64G Service Manual’’ (P/N 314001-03, 1992) – full schematics for 250425, 250469-A/B boards. | * ‘‘Commodore 64C/C64G Service Manual’’ (P/N 314001-03, 1992) – full schematics for 250425, 250469-A/B boards. | ||
* ‘‘Commodore Semiconductor Group Data Book’’ (1989) – electrical specs for 8500, 8562/8565, 8580, 251715. | * ‘‘Commodore Semiconductor Group Data Book’’ (1989) – electrical specs for 8500, 8562/8565, 8580, 251715. | ||
* ‘‘Commodore 64 Programmer’s Reference Guide’’ – unchanged from the bread-bin edition (all software compatible). | * ‘‘Commodore 64 Programmer’s Reference Guide’’ – unchanged from the bread-bin edition (all software compatible). | ||
== | == Gallery == | ||
<gallery mode="packed" heights="180"> | <gallery mode="packed" heights="180"> | ||
File:Commodore 64C - PD.jpg|Front view of a 64C | File:Commodore 64C - PD.jpg|Front view of a 64C | ||
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</gallery> | </gallery> | ||
== | == Related Pages == | ||
* [[Commodore 64 Troubleshooting Guide]] – applies to early C64C boards with 906114-01 PLA | * [[Commodore 64 Troubleshooting Guide]] – applies to early C64C boards with 906114-01 PLA | ||
* [[Commodore 64C Troubleshooting Guide]] – short-board-specific diagnostics | * [[Commodore 64C Troubleshooting Guide]] – short-board-specific diagnostics | ||