Apple AppleVision 1710 Display Troubleshooting Guide

Apple's test points: convergence controls on the CRT/video board (A), BM1 pin 14 and BM4 pin 8 on the intermediate board (B), DP6-DP10 and TRP1 pin A on the main deflection board (C) (Apple service guide, 1996)

Fault-finding for the AppleVision 1710 and 1710AV, from Apple's Service Source (revised in 1998) and the AppleVision chapter of Apple's 1996 displays service guide, which adds flowcharts with supply voltages. Apple notes that many modules returned for repair were found to work; read the first checks before replacing anything, and let the display warm up for about 20 minutes.

The CRT anode runs at 26 kV. Follow the CRT Discharge Procedure before working inside, and keep one hand away from the chassis during the live checks below.

First checks

• Check the serial number. Displays numbered SG522xxxxxx to SG536xxxxxx were referred to Apple for whole-unit or head-unit replacement; Apple's repair programme for units up to SG628xxxxxx with no video or no power ended on 31 December 1998.
• The display synchronises to 30-80 kHz horizontal and 50-120 Hz vertical; some computers need a video card.
• The raster is never a perfect rectangle and colour purity is never perfect. Magnetised metal furniture causes bowing and colour blotches; fluorescent lights and appliances cause jitter. If the picture changes when the display is moved, the location is the cause.
• A misadjusted display can look like a failed main deflection board or CRT.
• As a known-good test monitor, do not use another AppleVision or ColorSync display; it can make the AppleVision software behave erratically.
• CRT arcing can reset the microcontroller and blank the screen or upset geometry and convergence, especially in the first days after installation. Switch off at the front panel, or unplug the power and ADB cables and count to ten.

Apple's symptom charts

Symptom charts (Service Source, Troubleshooting pp. 4-10)

Symptom	Cures, in Apple's order
Black screen, power light on	Check the computer with a known-good monitor and the video and ADB cables. Turn up brightness and contrast. Check for high voltage (a rustling sound at switch-on or off); if present, use the recovery procedure below. Replace the main deflection board. Replace the CRT/video board where supported
Black screen, power light off	Check the power and that the computer is on, with ADB and video cables connected. Check the internal cables and that the CRT/video board is seated on the CRT socket. Replace the main deflection board. Replace the CRT/video board
Black screen after restart	Switch off at the front panel and on again (no damage results). Replace the main deflection board
Distorted shape, or distorted only at some resolutions	Check the resolution is supported. Click Factory Settings in Monitors & Sound. Replace the main deflection board. Replace the CRT/video board
Screen one colour	Check the CRT/video board is seated. Click Recalibrate. Use the recovery procedure. Replace the CRT/video board
Bands of colour across the screen	Degauss with a hand-held degaussing coil. Replace the main deflection board. Replace the CRT/video board
Very bright screen; may shut down	Recalibrate. Use the recovery procedure. Replace the main deflection board. Replace the CRT/video board
Poor focus	Set convergence in Monitors & Sound. Adjust H and V focus on the flyback transformer. Check the red and white wires in the CRT socket. Replace the main deflection board
Centre still blurred after focus and convergence	Adjust H-Stat on the CRT/video board. Adjust top and bottom convergence on the back of the CRT/video board. Check the CRT socket wires
Power light flashes in sleep; display cycles on and off; speakers click (1710AV)	Some 1710AVs misbehave in Energy Saver mode with a Power Macintosh 7200, 7500, 8500 or 9500 or some third-party cards. Serial numbers SG522 to SG536: use Sleep or Shut Down instead and have the unit replaced
A Logitech mouse moves nothing but the keyboard works	Some Logitech mice are incompatible with the display; it is not at fault
Two thin horizontal lines	Not a fault: the support wires of the Trinitron aperture grille

The 1996 service guide adds three symptoms: a narrow, one-inch vertical bar in the centre of the screen (replace the main deflection board); a thin red line at the left, right or top edge (adjust convergence in AppleVision Setup); and a single colour that recalibration cannot correct (delete the Display Preferences file, reset PRAM and reinstall the AppleVision software).

Microphone and sound faults on the 1710AV are on the 1710AV page.

Supply voltages and test points

Apple's 1996 service guide gives a no-video flowchart with test points on the main deflection board, which the later Service Source does not reproduce.

Test points (service guide, AppleVision 1710 chapter, pp. 84 and 88-89)

Test point	Board	Expected	If wrong
Anode, with Apple probe 076-0392	CRT	About 26 kV ± 1 kV (26 V on the meter)	Replace the main deflection board
TRP1 pin A	Main deflection board	3-4 V DC	Replace the main deflection board
DP6	Main deflection board	+180 V	Replace the main deflection board
DP7	Main deflection board	+65 V	Replace the main deflection board
DP8	Main deflection board	+12 V	Replace the main deflection board
DP9	Main deflection board	+6.3 V	Replace the main deflection board
DP10	Main deflection board	−11 V	Replace the main deflection board
BM1 pin 14, display switched off but plugged in and connected	Intermediate board	4-5 V DC	Check the BM1 connector and the cable to the CRT/video board
BM4 pin 8	Intermediate board	About 4.5 V DC	Replace the intermediate board

In the flowchart, if the high voltage, TRP1 and all five diode voltages are correct but there is still no picture, the CRT/video board is replaced. If the BM4 reading is right, the BM4 connector and its cable to the keypad are checked before the intermediate board is replaced. Apple notes that intermediate board faults mimic faults on the CRT/video board and main deflection board.

Diagnosing a hardware fault

The 1998 Service Source uses the Display Service Utility once cables, power, software and front-panel settings have been ruled out.

1. For a completely black screen, use a computer with a video card, with a known-good (non-AppleVision) monitor on the built-in port as the startup screen and the 1710 on the card.
2. Run the utility, select the AppleVision 1710/1710AV patterns and click Create File.
3. If it cannot communicate, open the display and measure between chassis ground and the end of resistor RL1 (390 Ω) nearest capacitor CP17 on the main deflection board. At 11.5-12.5 V, replace the CRT/video board; outside that range, replace the main deflection board.
4. If Create File succeeds, click Adjust Geometry, which checks the high voltage, and measure it with the probe. Correct high voltage points to the CRT/video board; none points to the main deflection board.

After any board change, adjust the display as described on the general maintenance page.

Recovering a blank or single-colour screen

A small proportion of 1710s and 1710AVs went blank, with the power light on and a rustle of high voltage, or turned a single colour with faint light at the edges, during startup or after recalibration. With Apple Display software 1.5.3 or later, start up holding Command-Option-A-V until a system alert sounds or the picture returns. With earlier software, Apple's AppleVision Recovery Utility was run with a known-good monitor as the startup screen and the 1710 on a second port, then the display was recalibrated. If the screen goes blank again during the next restart, Apple referred the display for repair.

Related pages

• Apple AppleVision 1710 Display
• Apple AppleVision 1710AV Display
• Apple AppleVision 1710 Display General Maintenance
• AppleVision 1710AV/1710 Service Source
• CRT Discharge Procedure