How to turn the Commodore back on after so many years / Diagnostics 586220 C64

Many have contacted me and asked me how to turn the Commodore back on, after so many years of inactivity, without causing damage. Let's see what to do to turn on (turn on) a computer (a Commodore 64, a Commodore 16, a Vic20, a C128 or an Amiga), after many years of inactivity, because you have recovered it from the cellar or you have just bought it.

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Obviously it would be advisable to send the computer to some good technician for checking. However, assuming you don't feel like doing it, or the vendor has assured you that your computer is working perfectly, you can take a few steps to reduce the risk of damaging it.

In addition to the ignition procedure, in this video we also see how to test the Commodore 64 with the special diagnostic kit 586220, both with the computer closed and with the computer open.

Check the power supply voltages

Being careful, you can connect the plug of the computer's power supply to the mains, but without connecting the other connector to the computer.

How to turn the Commodore back on after many years, power supply connector power supply capacitors voltage test, boot, biscuit, 64, 128, 16, Amiga, C16, C64, C128

After leaving the power supply on for a few moments, to check that it does not heat up and that it does not emit smoke or strange smells, you can turn it off to connect the test leads to the connector on the computer side.

How to turn the Commodore back on after so many years, C64 power supply voltage test with tester, 5V AC voltage test, tester, multimeter, boot

The measures are different for the various power supply models. Here are the slides with the pinouts, taking into account that the images are viewed from the power connector, with the pins facing the observer.

Pinout pins round DIN connector power supply power supply C64 Commodore 64 Vic20
Pinout pins square connector power supply C128 Commodore 128

Two measurements must be made on the Commodore Vic20, 64 and 128 power supply: one in alternating voltage (9Vac) and one in direct voltage (5Vdc). The tolerance on DC voltage is very small: voltages between 4.9V and 5.1V are allowed. There may be more tolerance on alternating voltage. The Commodore Vic20's power supply is the same as the Commodore 64 on most models.

Pinout pins square connector power supply Commodore Amiga power supply

For the Amiga power supply, three DC voltages must be measured, all with respect to pin 2 (GND). The voltages are 5Vdc and 12Vdc, with little tolerance.

Pinout pins round DIN connector power supply C16 Commodore 16

The Commodore 16 power supply has a single 9Vdc voltage, with a wide tolerance, taking into account that the positive is the external terminal.

Finding incorrect voltages, I recommend not to use the power supply. Furthermore, you must also check that the polarity is correct (if you find negative voltages where they should be positive, there is probably some wrong connection in the power connector).

When you turn off the power supply, the DC voltage is still present for a few moments, to testify that the electrolytic capacitors are working.

I recommend repeating the same measurements even after a few minutes of switching on the power supply.

There are those who recommend replacing the old power supply with a modern one. Of course, it is a good solution, but you have to choose a good power supply, with the appropriate protections and safety devices, built by a reliable technician.

How to turn the Commodore back on after so many years? Let's check the computer!

Let's continue the steps on how to turn the Commodore back on after so many years that it was turned off. It's time to check your computer.

Take a first look at all the connectors, which must appear as you see them in the picture, without oxide, without breakage or damage.

How to turn on the Commodore 64 ports joystick control port, power switch power supply
How to turn on the Commodore 64 expansion port port expansion antenna RF connector
How to turn on the Commodore 64 connector DIN IEC serial bus audio video AV datassette cassette user port

Inside you should not feel detached parts. If you hear something moving, it could be a screw (or other metal object) which, moving, could cause short circuits.

If you want to inspect the computer internally, in the video I show you how to open it.

After connecting the Commodore to the TV, as we see in the next paragraph, you can cross your fingers and… turn on the computer!

Do not leave the computer on for a long time. Just enough time to set up the TV and check if you can see the image.

If everything is in order, congratulations, the first part of the test went well!

You can power up the computer again, manually try the various keys on the keyboard and, perhaps, play some games with the joystick, also verifying that audio is heard. On my Youtube channel and on this site, I have already published several videos on how to load programs and games using the datassette, the floppy disk drive 1541, the emulator SD2IEC and other interfaces.

Connect the Commodore to the TV (TV)

To connect the Commodore to the TV, you can use an antenna cable or a composite audio / video cable.

Both of these solutions work with different Commodore models that we analyze in this article on how to turn the Commodore back on after so many years of inactivity.

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Regarding the antenna cable, also called RF cable, on one side it is provided with the RCA connector to connect to the computer. On the other hand, it must have the connector suitable for inserting into the antenna socket of the TV.

How to turn on the Commodore 64 connect television connector RF antenna cable analog channel 36 coaxial

The TV must have an analog tuner and be able to tune to channel 36.

How to turn the Commodore 64 back on connect television TV RF connector antenna cable analogue channel 36

Regarding the audio / video cable, on the Commodore side, the cable is equipped with a 5 or 8-pole DIN connector (depending on the model), on the TV side, the three RCA connectors must be connected to the audio (white and red) and video inputs composite (yellow).

How to turn the Commodore 64 back on connect television 8-pin DIN 5 audio video AV cable connector
How to turn the Commodore 64 back on connect television TV connector audio video AV cable left right composite video

If you buy a cable with a 5-pole DIN connector, you can use it on all the Commodores that we have seen in this video, as it is compatible with both 5-pole and 8-pole connectors. When you turn on the TV, you need to set the A / V input.

How to turn on the Commodore 64 connect television connector 5-pole AV composite audio video cable

Obviously, if you have other needs, such as using the S-Video signal, you will have to use pre-arranged cables. If your TV does not have audio / video or S-Video inputs and the antenna is digital only, you will need an RCA to HDMI converter.

586220 diagnostics for Commodore 64 – how to turn the Commodore back on after so many years

Even if you were lucky and your Commodore 64 turned on, I recommend that you continue reading this article on how to turn the Commodore back on after so many years from the last start. In fact, in the video, we see the 586220 diagnostic test for the Commodore 64.

It is possible to use only the interface to connect to the Commodore 64 expansion port. Connect the interface only when the computer is turned off. The complete test also consists of a series of connectors to be connected to the various ports of the Commodore 64.

How to turn the Commodore back on after so many years, diagnostic test 586220 C64, Kung Fu Flash CRT KFF

Instead of the diagnostic interface, you can use the Kung Fu Flash, obviously by loading the CRT file of the diagnostic test. Find this file at the bottom of this page.

Here are the three possibilities for starting the diagnostic test.

586220 diagnostic test without harness (also with Kung Fu Flash)

Without connecting the remaining connectors of the diagnostic test, the tests we can perform are limited and errors are still returned even if the computer is working.

How to turn the Commodore 64 back on diagnostic test cartridge 586220 C64 without harness connectors bad working, ram zero stack screen pla kernal basic rom charac cassette keyboard control port serial port user port timer1 timer2 timer interrupt sound test SID 4164 6510 6526 6567 6581 82S1 U7 U1 U2 U19 U18 U17 U9 U10 U11 U12 U21 U22 U23 U24 4066 c-64 diagnostic rev 586220 bad open ok

The test screen of a Commodore 64 (also working) is this, if we have not connected the various connectors of the diagnostic kit.

586220 diagnostic test with harness (also with Kung Fu Flash) and closed computer

Without disassembling the computer, you can try to connect almost any diagnostic test accessory, if you have them. When connecting them, care must be taken to insert the connectors in the right direction, with the computer off.

Also in this case it is possible to use the Kung Fu Flash instead of the interface to be connected to the expansion port.

How to turn the Commodore 64 diagnostic test cartridge 586220 C64 with harness connectors connected, Kung Fu Flash, KFF, CRT

After turning on the computer, the test is launched: the next image shows the result of a working computer. There is still the keyboard error, because we have not opened the computer and connected this last connector.

In fact, even without opening the Commodore 64, you can test it properly.

How to turn the Commodore 64 back on diagnostic test cartridge 586220 C64 with harness connectors connected keyboard open, ram zero stack screen pla kernal basic rom charac cassette keyboard control port serial port user port timer1 timer2 timer interrupt sound test SID 4164 6510 6526 6567 6581 82S1 U7 U1 U2 U19 U18 U17 U9 U10 U11 U12 U21 U22 U23 U24 4066 c-64 diagnostic rev 586220 ok

586220 diagnostic test with harness (also with Kung Fu Flash) and open computer

The video on how to turn the Commodore back on after many years of inactivity is full of information. It also shows how to open the Commodore 64 to inspect the interior. While the computer is open, you can check the state of the electrolytic capacitors. They must not be swollen and leak.

How to turn the Commodore 64 back on open disassembled 586220 C64 cartridge diagnostic test with harness connectors connected, Kung Fu Flash, KFF

With all connectors connected from the 586220 Diagnostic Kit, the test should not return any errors.

How to turn the Commodore 64 back on open diagnostic test cartridge 586220 C64 with harness connectors connected ram zero stack screen pla kernal basic rom charac cassette keyboard control port serial port user port timer1 timer2 timer interrupt sound test SID 4164 6510 6526 6567 6581 82S1 U7 U1 U2 U19 U18 U17 U9 U10 U11 U12 U21 U22 U23 U24 4066 c-64 diagnostic rev 586220 ok

Diagnostic interface rev. 586220 – how to turn the Commodore back on after many years of inactivity

As promised, here is the CRT file to be loaded with the Kung Fu Flash to emulate the diagnostic interface rev. 586220.

The file is in ZIP format. It must be unpacked and copied inside the Kung Fu Flash MicroSD.

Commodore 64 diagnostic interface 586220 CRT

Other diagnostic tests, games and utilities can be found in this link.

I hope this video was useful too! To be notified when more tutorials, other experiments and reviews related to retro computers and vintage electronics come out, I invite you to subscribe to the YouTube channel and activate the notification bell!

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Posted in Retro Computer, Retro Technology and Vintage Electronics, All articles.

2 Comments

  1. Hello great video and explanations on the page. I have some questions to ask, leaving aside the already excellent Kung Fu Flash, I am more interested in the diagnostic kit with the cables to be inserted in the ports of the C64 and the cartridge attached. Who provided it to him?

  2. howdy! Thank you so much for the compliments. I purchased the diagnostic kit on eBay. Simply look for the 586220 kit complete with harness. In particular, you will find kits to be assembled at an attractive price.

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