Common Hardware Problems and Commodore A500 and C64 Repair Information

Last updated on September 9th, 2023 at 02:46 pm

A list of things that can get you out of troubles

Known Hardware Problems on Amiga

Power supply: Before you start switching out chips, make sure you have a +12V and a -12V on your power supply. If not, then that’s where you need to start.
Battery: Remove old batteries from your Amiga Expansion Card, if you have one mounting it.
CIA faults: The CIA chips are responsible for a lot of the I/O on the Amiga. If you’re having problems with disk drives, serial ports, or the mouse, it could be a CIA fault.
ROM and RAM problems: If you’re experiencing software failure, it could be due to a problem with the ROM or RAM.
Screen colors and their meaning: If you’re seeing a dark grey screen, it means that the Amiga is disabling and clearing all interrupts. If the ROM is bad, the screen will be red. If an artificial exception occurs, the screen will be yellow. If memory is bad, the screen will be green.
IC components: A simple-to-use symptomatic guide for diagnosing faulty IC components on Amiga computers (includes all versions of the A500/1500/2000/2500).
Commodore 64 emulation: If you’re trying to emulate a Commodore 64 on your Amiga, it might not work well due to the need for more horsepower.
Custom chips: The Amiga OCS was not exploited in the same way as the C64’s VIC-II simply because the OCS was designed from the beginning to support.
Upgrading the CPU: The Amiga 500’s core system was largely the same with a few modifications such as having socketed chips. If you want to upgrade the CPU, you can do so by replacing the 68000 with a 68010 or 68020.

Remember to always be careful when repairing hardware and to follow proper safety procedures. If you’re not comfortable with repairing hardware, it’s best to seek the help of a professional.

Commodore A500 Repair

This system had multiple faults :

Corrosion from coffee, damaged Fat Agnus socket, dirty Floppy Drive, and faulty RAM.

I also talk briefly about the upgraded 8372A,

and the switch I added to toggle between 512Kb and 1Mb of Chip RAM.

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Here is a list of common hardware problems that can occur in Commodore 64:

Power supply: The power supply is a common problem in Commodore 64. It can cause issues such as a blank screen, a black screen with a white border, or a screen with vertical bars.

Bad chips: Bad chips can cause various issues such as a black screen, a blank screen, or a screen with vertical bars. The MOS chips have a different numbering system from the 74xx standard.

Bad RAM: Bad RAM can cause issues such as a black screen, a blank screen, or a screen with vertical bars.

Bad PLA: The PLA (Programmable Logic Array) is responsible for generating the video signals. A bad PLA can cause issues such as a black screen, a blank screen, or a screen with vertical bars.

Bad SID: The SID (Sound Interface Device) is responsible for generating sound. A bad SID can cause issues such as no sound or distorted sound.

Bad VIC-II: The VIC-II (Video Interface Chip) is responsible for generating the video signals. A bad VIC-II can cause issues such as a black screen, a blank screen, or a screen with vertical bars.

Bad keyboard: A bad keyboard can cause issues such as keys not working or keys sticking.

Bad disk drive: A bad disk drive can cause issues such as disk read errors or the disk drive not working at all.

Bad cartridge port: A bad cartridge port can cause issues such as cartridges not working or the computer not recognizing the cartridge.

Remember to always be careful when repairing hardware and to follow proper safety procedures. If you’re not comfortable with repairing hardware, it’s best to seek the help of a professional.

COMMODORE C64 REPAIR

Commodore 64 Rev C and 1541 electrolytic replacements:

Commodore 64 Rev C

QTY VAL OLD-rate NEW-rate Partnumber Note

12 10uf 25v 35v 70K9687
1 10uf 16v 25v 49W4526 4mm
1 470uf 6.3v 6.3v 39T9032
1 100uf 16v 25v 55K0210
1 2200uf 16v 40v 97M4010
1 470uf 25v 35v 96K3485
1 1000uf 25v 35v 30K6610

Early 1541

QTY VAL OLD-rate NEW-rate Partnumber

1 6800uf 25v 35v 688TTA035M
1 4700uf 16v 25v 478TTA025M
2 1uf 50v 63v 70K9709
2 47uf 16v 25v 55K2107
1 100uf 16v 25v 55K0210
1 220uf 10v 25v 65R2987