Service manual

3. DIAGNOSTIC CHECK
Service Manual BSM-4100 3.27
The DPU board is a separate subsystem from the MAIN board. The DPU board
consists of CPU, ROMs, RAMs, A to D converter and DMA.
D/A ADJUST
This item is used to check the output voltage level of the D/A converter.
Connect a digital multimeter or oscilloscope to the ZB-800P socket (Pin 4:
Ground, Pin 5: Analog output) and check the following output signals.
DPU Check Menu Items
D to A output
DC 0 V 0 V
±
10 mV
DC
−
V CHECK
−
5.120 V
±
1%
DC +V CHECK +5.1175 V
±
1%
AC 60/30 Hz 60 Hz
±
5%, 6 Vp-p
±
5%
Procedure to Start the D/A Adjust Check
1. To select the D/A Adjust Check, touch the “D/A ADJUST” key at the DPU
CHECK column. The program outputs 0 V DC.
The “DC 0V” key is highlighted to indicate the status of output.
2. To change the output voltage or waveform, touch each name of the other keys.
3. To return to the MANUAL CHECK MENU screen, touch the “RETURN” key.