Troubleshooting; Power Supply Troubleshooting - ELCOM Euro-500 Handy Series Service Manual

Euro-500TX Handy
This chapter contains the instructions for troubleshooting various malfunctions of the ECR Euro-500TX
Handy. This chapter features eight sections:

• power supply troubleshooting,

• microprocessor troubleshooting,
• printing troubleshooting,
• display troubleshooting,
• keyboard troubleshooting,
• communication troubleshooting,
• real-time and date troubleshooting,
• miscellaneous troubleshooting.
Every defined malfunction or error listed here contains its possible cause; the probably affected circuits are
listed, followed by a short description for the repair process.
Note: During the troubleshooting, stick to the recommended repair process, individual circuit descriptions
in chapter 2, and the overall ECR schemes. It is necessary to take into account that the malfunction can be
of a broader scope that may exceed the descriptions listed here. If any uncertainty as to the malfunction
origin, suspicion of a broad malfunction, or insufficient equipment to repair the malfunction, please entrust
the repair to the service centre in the seat of the company. Doing so, further damage to the ECR can be
avoided.
6.1 Power supply troubleshooting
• ECR doesn't function (external power supply connected)
damaged or disconnected main power switch
damaged cable between the main PCB and Intercon PCB
blown SMD fuse F2
damaged primary power supply + discharged accumulator
incorrect VCC voltage value
incorrect VRAM voltage value
Service manual

6 Troubleshooting

– check the switch cable connection into the main PCB
(PWRSW connector)
– check the switch functionality using the multi-meter
(look at the keyboard PCB)
– check the integrity of the 2-wire cable that connects
the connector PCB to main PCB using the multi-me-
ter
– check the proper plugging of the connector cable into
the main PBC (REAR2 connector)
– check the SMD fuse F2 (1.85 A) – replace
– check the proper voltage and polarity of the mains
adapter.
– check the proper connection of the accumulator into
the main PCB; connectors BATT1 and BATT2
– check the output voltage of the primary power supply
(low voltage is mainly due a damaged accumulator
– replace it)
– the primary power supply voltage is too low or zero
–all of the primary power supply shall be measured
(most sensitive parts are U13, D1–D3)
– check the Charger circuit charging voltage
– check whether the NMI reaches the 4.5 V value after
the main power switch is turned on, depending on the
accumulator (if not, check U12, R5, R6, C13)
– damaged D4 diode – replace
– check whether the VRAM power supply is not short-
circuited toward GND (damaged semiconductive
part)
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