Commodore 128D 100% NOT tested, does it work?

I present to you my “new” 100% NOT tested Commodore 128D, which I purchased on eBay. Shall we try it? In your opinion, will it work?

Purchase of the Commodore 128D 100% NOT tested

I occasionally buy some vintage computers for my collection. Unfortunately, sometimes it happens to receive computers that do not work, despite being declared as perfectly fine. Or, it happens to receive computers ruined due to inadequate packaging.

This time, the premises are even worse: will this 100% UNTESTED Commodore 128D, purchased on eBay, work?

In addition to the Commodore 128D and the keyboard with German layout, there are also a number of accessories that have little to do with the Commodore 128. There are two power supplies of the Commodore 64, an external drive power supply (which can be the 1581, for example), and an external Commodore 1541 drive (which does not require an external power supply, though...).

Here is the "new" Commodore 128D 100% NOT tested!

A few days after purchase, I received the 100% UNTESTED Commodore 128D. Here it is, in all its splendor. Work? Won't it work? We'll find out shortly. All the tools present near the computer are used precisely to find out.

The keyboard has a German layout, in fact the Commodore 128D comes from Austria. The case is plastic, with side handle. The keyboard can be housed at the bottom of the case, which has a special compartment.

Check supply voltages of the Commodore 128D

Unlike the Commodore 64, Commodore 128 and other home computer models, the Commodore 128D has an internal power supply. Before connecting it to the mains and turning it on, it is advisable to check the supply voltages. They must be corrected! I had written this article To learn more: I invite you to read it.

To check the power supply voltages of the vintage computer, you have to open it. There are four screws to unscrew, at the bottom.

Before giving voltage to the power supply, we detach the two connectors that bring power to the internal floppy disk drive controller and to the motherboard of the computer.

The goal is to be able to power the computer, test the voltages with the tester, but without any incorrect voltages reaching the computer cards.

The voltages to be verified are:

• 5V direct current, for computer logic;
• 12V direct current, for floppy disk drive;
• 9V in alternating for the SID (on this voltage there is a lot of tolerance).

Thankfully, in this 100% UNTESTED Commodore 128D, the voltages are correct.

First power on of the Commodore 128D

After reconnecting the two connectors that we disconnected to test the supply voltages, we can try to power the computer. To my surprise, Commodore 128D 100% NOT tested… works!

On closer inspection, it was found that the computer's internal floppy disk drive cannot read the floppy disks.

The Commodore 128D allows you to use two monitors

This is a speech that I had already deepened in this article: the Commodore 128 (as well as the Commodore 128D) allows you to use two monitors, one with 40 columns of text, one with 80 columns.

To connect a VGA monitor to the RGBI output (the 80-column output of the Commodore 128), you need a specific adapter, as well as a monitor that supports a horizontal synchronism of 15 kHz. Typically, however, monitors support synchronisms starting at 31 kHz. So, most likely, a randomly chosen monitor will not fit.

Although you only see one monitor used at a time, the C128 actually allows you to use both monitors so that they display different text (or images).

More in-depth test: the diagnostic test 586220

To carry out a more thorough test of the peripherals and circuits of the Commodore 128D, we can use the diagnostic test 586220, which I had already reviewed in this article. It works for the Commodore 64 and the Commodore 128.

The 586220 diagnostic test consists of an interface to be inserted into the expansion port, as well as other interfaces to be inserted into the various ports on the computer. In the image below, you can see the red diagnostic cards.

When you turn it on, the computer starts with the diagnostic screen of the Commodore 64 version 586220. The computer performs several tests (ROM, RAM, SID, computer ports, etc.).

My Commodore 128D 100% NOT tested may have some problems with the user port. I don't think it's a difficult problem to solve: either there is an interrupted track on the printed circuit board, or there is an integrated fault (diagnostics already indicate which integrated ones may be responsible).

What do you say, I'm happy with this Commodore 128D 100% NOT tested?

Would you be satisfied with such a purchase, bought as 100% untested and finding it in these conditions, still working?

I consider myself quite satisfied, also given the previous experiences, in which I bought things that worked, which then did not work. While we're at it, I remind you to subscribe to the YouTube channel and activate the notification bell.

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