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Old 21st Mar 2021, 7:23 pm   #64
GeraldSommariva
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Join Date: Mar 2021
Location: Liphook, Hampshire, UK
Posts: 125
Default Re: The Transam Triton Personal Computer

Fired up the Triton main board today and as expected its not working.

Based on the first look see I have found a number of problems:-

The Keyboard is putting -12v on some of the keyboard buffer TTL data input pins IC49.

IC49 (74LS244) is holding DB8 to near zero but if the Keyboard is unplugged it returns to +5 but DB8 is connected to its input pin 11 even though the select pins and 19 are high.

The VDU chips seams dead IC61 (SFC96364) but there is a clock on pin 2, is this chip still available ?

Has anyone got a example of what the waveform should look like on pin 2 ?

This is going to be more of a challenge than I expected.
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