HP Compaq dc7800 User Manual

System does not power on and the LEDs on the front of the computer are not flashing.
Cause Solution
3. Check that both power supply cables are properly
connected to the system board.
4. Check to see if the 5V_aux light on the system board is
turned on. If it is turned on, then replace the power button
harness.
5. If the 5V_aux light on the system board is off, then replace
the power supply.
6. Replace the system board.
Solving Power Problems
Common causes and solutions for power problems are listed in the following table.
Table D-2 Solving Power Problems
Power supply shuts down intermittently.
Cause
Solution
Voltage selector switch on rear of computer chassis (some
models) not switched to correct line voltage (115V or 230V).
Select the proper AC voltage using the selector switch.
Power supply will not turn on because of internal power supply
fault.
Contact an authorized service provider to replace the power
supply.
Computer powered off automatically and the Power LED flashes Red two times, once every second, followed by a two
second pause, and the computer beeps two times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause
Solution
Processor thermal protection activated:
A fan may be blocked or not turning.
OR
The heatsink is not properly attached to the processor.
1. Ensure that the computer air vents are not blocked and
the processor cooling fan is running.
2. Open hood, press power button, and see if the processor
fan spins. If the processor fan is not spinning, make sure
the fan's cable is plugged onto the system board header.
3. If fan is plugged in, but is not spinning, then replace the
heatsink/fan assembly.
4. Contact an authorized reseller or service provider.
Table D-1 Solving General Problems (continued)
222 Appendix D Troubleshooting Without Diagnostics

HP Compaq dc7800 Specifications

General

Tcase	73.3 °C
Bus type	FSB
Stepping	M0
Processor cache	2 MB
Processor cores	2
Processor model	E4600
System bus rate	- GT/s
Processor family	Intel® Core™2 Duo
Processor series	Intel Core 2 Duo E4000 Series
Processor socket	LGA 775 (Socket T)
Processor codename	Conroe
Processing Die size	111 mm²
Processor frequency	2.4 GHz
Processor cache type	L2
Processor lithography	65 nm
Processor manufacturer	Intel
Processor front side bus	800 MHz
Processor operating modes	64-bit
ECC supported by processor	No
Thermal Design Power (TDP)	65 W
CPU multiplier (bus/core ratio)	12
Number of Processing Die Transistors	167 M
Internal memory	1 GB
Internal memory type	DDR2-SDRAM
Maximum internal memory	8 GB
Memory layout (slots x size)	2 x 0.5 GB
HDD speed	7200 RPM
HDD interface	SATA
Optical drive type	DVD Super Multi
Total storage capacity	160 GB
Audio input	1
LightScribe	Yes
Networking features	Intel 82566DM Gigabit Network Connection
Graphics card RAMDAC	400 MHz
Storage drive controller	SATA 3, 0 Gb/s NCQ SMART VI
Discrete graphics card model	Intel® GMA 3100
Maximum graphics card memory	0.256 GB
Operating system installed	Windows Vista Business
USB 2.0 ports quantity	8
Chassis type	Mini Tower
Country of origin	China
Cable lock slot type	Kensington
Operating altitude	0 - 3048 m
Non-operating altitude	0 - 9144 m
Storage temperature (T-T)	-30 - 60 °C
Operating temperature (T-T)	10 - 35 °C
Storage relative humidity (H-H)	5 - 95 %
Operating relative humidity (H-H)	10 - 90 %
Power supply	365 W
Product type	PC
Processor code	SLA94
Processor ARK ID	32242
Processor package size	37.5 x 37.5 mm

Weight and Dimensions

Depth	452 mm
Width	177 mm
Height	447 mm
Weight	11800 g