B/W M20 video cable pinout
by Davide BucciThe video cable brings the power supply to the black and white monitor, as well as the video signals. In this page, we describe the pinout of the cable.
The connectors
First, let us have a look at the output of the M20. In the following picture, there is the M20 connector pinout, as reported by the hardware manual of the M20 (see the Manuals section of this site). Imagine standing in front of the backside of the M20 and watching the pins of this male edge connector.
The cable is equipped with a female edge connector, with a metallic key which prevents it to be inserted in the wrong way. I do not understand why in the Olivetti's documentation the key is not represented clearly... However, here is the connector mounted on the cable for a black and white M20, holding the connector towards you. You might notice that only a handful of pins are indeed used in the connector.
You might notice that the numbering and the connections are mirrored, due to the different way to represent the connector. Inside the monitor, the cable is attached to a small power supply board via a 8 pin connector. The female is mounted on the cable and the connections are as follows.
Here once again, image taking the connector in your hand and watching it in the side where the holes are present.
Connections
| Pin on the M20 side | Pin on internal connector | Signal description |
|---|---|---|
| 12 | 8 | HSYNC |
| 14 | 2 | +12V |
| 15 | 7 | GND (coax shield) |
| 16 | 5 | VIDEO B/W (coax, 50 ohms?) |
| 17 | none | GND |
| 18 | 3 and 4 | GND (power) |
| 20 | 6 | VSYNC |
| 22 | 1 | +12V |
Pictures
The monitor internals. The cable is attached to the connector on the little vertical board with the green soldermask.
A detailed view of the two connectors, external and internal. The pins present on the M20 side are clearly visible. A careful examination reveals that the video signal is brought by a coaxial cable, kept separate from all the other signals.
Page log
- December 23, 2022 - Added this page log, light editing.
- August 8, 2012 - First version of this page.
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