20" ColorSync Displays Service Source
The 20" ColorSync Displays volume of Apple's Service Source is the field-service manual for the AppleVision 850 and AppleVision 850AV displays. The file is 177 pages.
The product this covers, and its two names
[edit | edit source]Apple renamed these displays in November 1997. The manual's Product Name Change page (p. 8) gives the mapping and states that the body of the manual keeps the AppleVision names:
| Original name | Name from November 1997 |
|---|---|
| AppleVision 850 Display | 20" (19.0" VIS) ColorSync Display |
| AppleVision 850AV Display | 20" (19.0" VIS) ColorSync AV Display |
The name change was the only change to the product. Note the two figures in the name: the tube is 20 inches, the viewable image is 19.0 inches.
Contents
[edit | edit source]- Hot Issues — Introduction, jittery or blurry video with Power Macintosh 5500/6500, identifying suspect units (pp. 3–5)
- Basics — Product Name Change, Overview, Features, Repair Issue: Display Service Utility, Repair Issue: TCO 95 Housing (pp. 8–14)
- Specifications — Picture Tube, Factory Preset Screen Resolutions, Input Signals, Scan Rates, Cable Connector, System Requirements, ten pages of Monitor Timings, Audio (850AV only), Controls and Ports, Physical and Electrical, Environmental (pp. 16–38)
- Data Sheet (p. 39)
- Troubleshooting — General, First Checklist, symptom charts for No Raster, Geometry, Screen Color, Screen Brightness, Focus and Miscellaneous; Adjusting Screen Convergence; Downloading Setup Parameters and Replacing the CRT/Video Board; adjusting after replacing either board; Checking High Voltage (p. 59); Diagnosing a Suspected Hardware Problem and its flowchart (pp. 42–63)
- Take Apart — Safety Guidelines, List of Tools, Model Differences, Blank Plate/Microphone, Front Bezel, Top Housing, Rear Housing, Mid Housing, CRT/Video Board, Video Cable, Main Deflection Board, Tilt-Swivel Base, Bottom Housing, ADB Board (850 only), Sound Enclosure and Bezel, Audio Cable, Endcaps, Speaker, Sound Board, Heatsink in Sound Enclosure, Power Board (850AV only) (pp. 65–173)
- Adjustments — Adjusting the Display (p. 175)
- Exploded View (p. 177)
Specifications as printed
[edit | edit source]| Item | Value |
|---|---|
| Picture tube | 20 in Trinitron, 19.0 in viewable image; multiple scan; multilayer anti-reflection panel to TCO 92; 0.26 mm stripe pitch, 0.25 mm grille pitch |
| Mains input | 90–264 V AC, 47–63 Hz — full-range, unlike the 750/750AV |
| Power | 150 W maximum (850); 190 W maximum (850AV) |
| Monitor stand | Built-in tilt-and-swivel; tilt −5° to +15°; swivel ±45° minimum |
Factory-preset resolutions start at 640×480 at 60 Hz (VGA) and run through 640×480 at 67 Hz (Macintosh), 72, 75 and 85 Hz (VESA), 800×600 at 56/60/72 Hz and upward — ten pages of monitor timings in all.
What this manual settles
[edit | edit source]{These are live-chassis measurements taken with the display running and the covers off. Read CRT Discharge Procedure first. The anode holds a lethal charge after the set is unplugged, and Apple's own procedure requires a second person to be present.}
The 850 takes a full-range supply. Where the 17" AppleVision 750 specifies "100–120 V AC and 220–240 V AC", the 850 specifies a single 90–264 V AC, 47–63 Hz range. That is the more useful fact for anyone running one on the opposite mains supply from the one it was sold on.
High voltage is checked with Apple probe 076-0392, and Apple states that no other high-voltage probe will give an accurate reading. Getting to the anode on this display means removing the blank plate/microphone, top housing, rear housing, front bezel and mid housing — considerably more disassembly than the 17". A reading of 0 V DC means the main deflection board is replaced, after which the display must be readjusted by the procedure in the same chapter.
Only the 850AV has a separate power board; on the 850 the Take Apart chapter has no such entry. The ADB board is fitted to the 850 only.
A documented system-level fault, not a display fault: jittery or blurry video with a Power Macintosh 5500 or 6500. Hot Issues gives the identification criteria.
What this manual does not contain
[edit | edit source]No schematic, no component-level parts list, no capacitor list and no internal rail voltages. The only measured electrical figure is the anode check.
Related documentation on this wiki
[edit | edit source]- 17" ColorSync Displays Service Source — the AppleVision 750/750AV, renamed at the same time
- Studio Display (21" CRT, 19.8" viewable image size) Service Source — which does publish a power-board test point and its adjustment
- Macintosh 21 Color Display Service Source · Macintosh Color Display Service Source · Apple Multiple Scan 720 Display Service Source
- CRT Discharge Procedure · Capacitor Failure Symptoms
Download the 20" ColorSync Displays Service Source here: colorsync_20_displays.pdf (6.2 MB)