...
Typical waveforms and voltages taken from a serviceable unit with the Index displayed are set out in Tables 4.1, 4.2 and 4.3 below. Voltages present when the Z88 is in the coma state are listed in Table 4.4.
If, when the two SHIFT keys are depressed, the Index is displayed it can be assumed that most of the system is working. If it is possible to select Pipedream and generate and store a file, then it can be assumed that the basic system is healthy.
...
| Test Point | Voltage |
|---|---|
| SK8, pin 12 | +5.5V |
| R9 | +16.3V |
| R38 | -6.0V |
| T8 emitter | -18.0V |
Table 4.2 - Typical VoltagesAnchor T42 T42
| Transistor | Emitter | Base | Collector |
|---|---|---|---|
| T1 | +0.4V | 0.0V | -0.4V |
| T2 | -0.3V | -0.4V | -5.6V |
| T3 | 0.0V | 0.0V | -0.3V |
| T4 | 0.0V | -0.3V | -6.1V |
| T5 | 0.0V | -6.2V | -5.6V |
| T6 | +5.5V | +4.9V | +5.4V |
| T7 | +0.4V | 0.0V | -18.0V |
| T8 | -18.0V | -18.0V | +5.5V |
| T9 | 0.0V | 0.0V | +5.0V |
| T10 | 0.0V | -0.4V | +5.0V |
| T11 | +5.5V | +5.5V | -5.8V |
| T12 | +5.5V | +4.9V | +5.5V |
| T13 | +0.5V | 0.0V | -5.3V |
| T14 | -5.4V | -5.6V | -6.0V |
| T15 | +5.5V | +5.5V | -6.0V |
| T16 | -5.9V | -5.3V | -6.0V |
| T17 | +5.5V | +4.8V | +5.5V |
| T18 | +2.7V | +2.3V | +5.5V |
| T19 | 0.0V | -0.5V | +2.7V |
| T20 | +14.0V | +14.0V | +5.3V |
| T21 | 0.0V | 0.0V | +14.0V |
| T22 | 0.0V | +0.2V | +2.8V |
| T23 | +5.5V | +5.1V | +.2.8V |
| T24 | +5.5V | +6.0V | +2.8V |
| T25 | -0.9V | 0.0V | +5.0V |
Table 4.3 - Typical Waveforms and VoltagesAnchor T43 T43
| Test point | Waveform |
|---|---|
| General | |
| R44 | 5.5V sinewave 9.8304 MHz (MCK) NOTE: Before attempting to measure this signal, refer to the CAUTION on page 4.4 |
| C18 | 5.2V sinewave 25.6 KHz |
| T24 | Collector 5.2V squarwave 25.6 KHz (SCK) |
| C21 | 40 uS reset pulse, negative going (press Reset switch) |
| T25 | Collector +5.0V sense line (SNS) |
| C14 | +2.4V (LP) |
| IC1 | |
| Pin 6 | Squarewave 5.5V 3.2768 MHz (Z80 clock) |
| Pin 11 | +5.5V |
| Pin 16 | Negative going 5.5V pulses, 100 Hz (/INT) |
| Pin 17 | Negative going 5.5V pulses, 100 Hz (/NMI) |
| Pin 18 | Negative going 5.5V pulses, 100 Hz (/HALT) |
| Pin 20 | Negative going 5.5V pulses, 100 Hz (/IORQ) |
| Pin 26 | Negative going reset pulse, (/RST, press Reset switch) |
| Display SK5 | |
| Pin 1 | +5.5V |
| Pin 3 | -6.6V to -10.5V variable by RV1 |
| Pin 4 | +5.5V pulses, 300 nS pulse width, period 156 uS |
| Pin 5 | 5.5V squarewave 50 Hz (FR) |
| Pin 6 | +5.5V |
| Pins 8,11,12,13,14 | Data |
| Pin 9 | 5.5V squarewave 3 MHz (display shift clock, XSCL) |
Table 4.4 - Coma VoltagesAnchor T44 T44
...