Editing Schematic Notes for Video Board

'''''Supplement to Schematic for Display Circuit''''' — Commodore Business Machines, Inc. A single typed sheet giving '''the oscilloscope settings for each of the fourteen waveform photographs''' printed on the [[Commodore PET 2001]] display circuit schematic.

'''This is not a set of notes about the video board.''' It is one specific thing: the vertical sensitivity and timebase that go with each numbered waveform photograph on [[Video Board Schematic]]. Without it, those photographs cannot be compared against a real measurement, because the scale they were taken at is not printed beside them. The two documents are useless apart.

== The settings, as printed ==
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table"
|-
! Picture !! Vertical !! Timebase !! Note
|-
| 1 || 1 V || 5 ms ||
|-
| 2 || 5 V || 2 ms ||
|-
| 3 || 1 V || 20 µs ||
|-
| 4 || 10 V || 0.5 ms ||
|-
| 5 || 0.2 V || 0.2 ms ||
|-
| 6 || 5 V || 5 ms ||
|-
| 7 || 0.5 V || 5 ms ||
|-
| 8 || 0.5 V || 20 µs ||
|-
| 9 || 0.5 V || 20 µs || '''11.6 V peak'''
|-
| 10 || 0.2 V || 20 µs ||
|-
| 11 || 5 V || 20 µs ||
|-
| 12 || 1 V || 20 µs ||
|-
| 13 || 20 V || 20 µs ||
|-
| 14 || 5 V || 5 ms ||
|}

Commodore's sheet writes these as "mil sec" and "micro sec"; they are milliseconds and microseconds per division, and the voltage figures are volts per division. '''Picture 9 is the only one with an absolute figure against it: 11.6 V peak.''' That is the single measurable number in the document, and it is the only amplitude Commodore published for any of the fourteen test points.

== What it does not contain ==
It does not say '''where''' each photograph was taken — the numbered test points are on the schematic itself, not here. It carries no component values, no rail voltages and no fault information.

{{Warning|The display assembly is the PET's power supply as well as its monitor. Mains voltage is present on it whenever the machine is plugged in, the CRT anode runs at roughly +10 kV from flyback T2, and C1 is a 4700 µF reservoir that stores real energy. Read [[CRT Discharge Procedure]] before working on this board.}}

== Related pages ==
* [[Video Board Schematic]] — the sheet these settings belong to
* [[Video Board Parts Layout]] · [[Video Board Parts List (1 of 3)]]
* [[Commodore PET 2001 Service Documentation]] · [[Commodore PET 2001 Troubleshooting]] · [[CRT Discharge Procedure]]

[[File:notes-2.gif|thumb|600px|Commodore's ''Supplement to Schematic for Display Circuit'' — the oscilloscope settings for the fourteen waveform photographs.]]

Download: [[:File:notes-2.gif|notes-2.gif]]

[[Category:Commodore PET 2001 Schematics]]
[[Category:Commodore Documentation]]