(347) 552-2258 [email protected]

820-2530 no chime, no video-green light & power

galvestonmac

galvestonmac

New member
I just got in an 820-2530 with liquid damage. Green light on charger and I can short the pins to turn it on. No chime, high fan spin & no video to LCD or external. Q9806 was not looking nice and had very low readings on pins. Checked around and R9808, C9802 & R9809 are within spec.I replaced and now I have 0 volts on pins 1,2 & 6. 9.70v on pin 3, 12.6v on pin 4 & .03v on pin 5

Before chasing the no video issue what else should I be looking for with no chime and the high fan spin? Thanks!
 
larossmann

larossmann

Administrator
Staff member
The resistors around U6100 are the first suspect. After that check CPU & MCP vcore. After that I would give the MCP a light heating and see what happens.
 
galvestonmac

galvestonmac

New member
Resistance to GND on PP3V42=.393
PPVCORE_S0_MCP=.99v
PPVCORE_S0_CPU=1.05v

Seem to be missing PPBUS_S0_LCDBKLT_PWR
Heated U1400 a little see if any change, nothing different

Getting PPBUS_S0_LCDBKLT at pin 4 of Q9806, but other measurements are off on Q9806.
Replaced Q9806-no change
1=2.58v
2=3.25v
3=9.69v
4=12.6v
5=.39v
6=.40v

Getting .42v at R9700 pin 1 for PPBUS_SO_LCDBKLT_PWR

Q9807
2=0v
3=8.61v
4=.01v
5=0v
6=.03v
Missing BKLT_PLT_RST_L & LVDS_IG_BKL_ON

R9841, R9840 & R2892 are correct readings
R2151 & R2150 are correct readings

I'm thinking something got cooked and this might end up a donor board? This is an old machine, yes, but I'm fixing it for an Iraq vet that's getting squared away back to civvy life.

Thanks!
 
D

dukefawks

Administrator
I asked for resistance on 3V42 not diode mode....
Also it makes no sense to check backlight if the board isn't even chiming.
 
Gurmon

Gurmon

Member
You don't measure resistance on a live circuit.

Remove all power from board, set your multimetre to Ohms. Red probe on 3.42v Rail, black probe on ground.

It may be 30 secs before your multimeter will give an accurate resistance reading.

Depending on this reading, we can determine if your boards MCP is faulty. Then you can throw this board in the donor pile.
 
galvestonmac

galvestonmac

New member
PP3V42 measured at pin 1 of R5140 is 28.1 at 200K on multimeter. What is the reading normally supposed to be? I don't have another of the same type compare. thanks
 
D

dukefawks

Administrator
This board is brain dead and could be anything. Corroded resistor/trace somewhere or a dead MCP are the 2 most likely suspects.
 
You must log in or register to reply here.
Top