Schematic Notes for Video Board: Difference between revisions
Auto-created Commodore PET 2001 schematic page |
Remove wrong claim that mains reaches the display board; quote the sheet; cite zimmers and the display schematic; copyedit |
||
| (2 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
[[ | '''Schematic Notes for Video Board''' holds Commodore's ''Supplement to Schematic for Display Circuit'', a single typed page on Commodore Business Machines letterhead (901 California Avenue, Palo Alto, California). It gives the oscilloscope settings for the fourteen waveform photographs printed on the [[Commodore PET 2001]] display circuit schematic, held here as [[Video Board Schematic]]. The sheet opens: "The following data should accompany each of the photographs". The scan is notes-2.gif from the PET 2001 schematics directory at zimmers.net, which describes it as "Notes to go with video board schematic".<ref name="zimmers">{{cite web |url=http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/2001/ |title=/pub/cbm/schematics/computers/pet/2001/ |website=zimmers.net |access-date=2026-10-01}}</ref> | ||
Download | == 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 writes each line as a voltage and a time ("1V 5 mil sec", "1V 20 micro sec") without saying "per division". Picture 9 is the only one with an amplitude against it, "11.6V peak". | |||
== What it does not contain == | |||
The page does not say where each photograph was taken. The numbered test points, circled 1 to 14, are marked on the display circuit schematic itself. The page has no component values, rail voltages or fault information. | |||
{{Warning|The CRT anode runs at about +10 kV from flyback T2 on the display board, and the tube holds its charge after power-off. Read [[CRT Discharge Procedure]] before working on the display board.<ref name="video">Commodore Business Machines, ''Schematic, Service, Display Circuit'', hosted as [[:File:Video-1.gif]]. Shows the fourteen waveform photographs and the circled test points 1-14, the +10 kV output of flyback T2, bridge CR19-CR22, reservoir C1 4700 µF 25 V and regulator VR1 (78/12) for +12 V.</ref>}} | |||
== Related pages == | |||
* [[Video Board Schematic]], the drawing these settings belong to | |||
* [[Video Board Parts Layout]] | |||
* [[Video Board Parts List (1 of 3)]] | |||
* [[Commodore PET 2001 Service Documentation]] | |||
* [[Commodore PET 2001 Troubleshooting]] | |||
[[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]] | |||
== References == | |||
<references /> | |||
[[Category:Commodore PET 2001 Schematics]] | [[Category:Commodore PET 2001 Schematics]] | ||
[[Category:Commodore Documentation]] | |||
Latest revision as of 14:03, 1 October 2026
Schematic Notes for Video Board holds Commodore's Supplement to Schematic for Display Circuit, a single typed page on Commodore Business Machines letterhead (901 California Avenue, Palo Alto, California). It gives the oscilloscope settings for the fourteen waveform photographs printed on the Commodore PET 2001 display circuit schematic, held here as Video Board Schematic. The sheet opens: "The following data should accompany each of the photographs". The scan is notes-2.gif from the PET 2001 schematics directory at zimmers.net, which describes it as "Notes to go with video board schematic".[1]
The settings, as printed
[edit | edit source]| 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 writes each line as a voltage and a time ("1V 5 mil sec", "1V 20 micro sec") without saying "per division". Picture 9 is the only one with an amplitude against it, "11.6V peak".
What it does not contain
[edit | edit source]The page does not say where each photograph was taken. The numbered test points, circled 1 to 14, are marked on the display circuit schematic itself. The page has no component values, rail voltages or fault information.
 | The CRT anode runs at about +10 kV from flyback T2 on the display board, and the tube holds its charge after power-off. Read CRT Discharge Procedure before working on the display board.[2] |
Related pages
[edit | edit source]- Video Board Schematic, the drawing these settings belong to
- Video Board Parts Layout
- Video Board Parts List (1 of 3)
- Commodore PET 2001 Service Documentation
- Commodore PET 2001 Troubleshooting
Download: notes-2.gif
References
[edit | edit source]- ↑ /pub/cbm/schematics/computers/pet/2001/—link(accessed 2026-10-01)
- ↑ Commodore Business Machines, Schematic, Service, Display Circuit, hosted as File:Video-1.gif. Shows the fourteen waveform photographs and the circled test points 1-14, the +10 kV output of flyback T2, bridge CR19-CR22, reservoir C1 4700 µF 25 V and regulator VR1 (78/12) for +12 V.
