Restoration of the Intel MCS-80
System Design Kit

I managed to purchase an Intel SDK-80 (technical specifications and schematics are available in Intel Systems section) on one of the online auction platforms in a fairly good condition. The previous owner did not complete the assembly, and it seems like they never powered up the kit. The integrated circuit set was unused, except for two 8111 memory chips, which were also missing from the board. Thanks to this, it is possible to see the kit’s components in the state they were in at the time of the SDK-80 purchase.

I decided to remove all the elements from the printed circuit board to be able to scan the unpopulated board; perhaps it will serve as a source for creating a replica in the future. After removing all the elements, the printed board was scanned in high resolution.

In the next step, I proceeded to assemble the SDK-80. All the locations for integrated circuits were equipped with period-accurate sockets.

The remaining elements were soldered back into their original positions.

After inserting the integrated circuits (intel 8080A, 8224, 8228) obtained from another of my printed circuit board (from the same period), the SDK-80 looked like this.

Due to the preservation of the integrated circuit set in an unchanged state, I programmed the SDK-80 monitor into the EEPROM 28C16 and used a simple converter of this type of memory for the 2708 circuit.

Unfortunately, powering up the board turned out to be a complete failure. The board lacked +12V voltage. It turned out that capacitor C16 (22uF) was shorted to ground. After replacing this component, all voltages: +5V, +12V, and -12V, as well as those generated by the 7905 circuit (-5V), were present on the board.

After fixing the jumpers configuration

and after setting the parameters of the RS232:

Transmission speed: 2400 baud
Number of characters: 8
Parity control: none
Number of stop bits: 2

I finally received the message: