Three Beep of Death

[Rford]

I realize what the three beep of death means typically, have also tried resetting everything... Has anyone found other causes of this beside RAM? Anyone have any luck changing out RAM? The board is 820-3437.

 

[dukefawks]

Was this board liquid damaged, how did this happen?

 

[Rford]

it was liquid damaged. I found a number of missing power rails, and was able to repair them. It was also US cleaned.

 

[dukefawks]

Check voltage on L7430. Also check if any of the RAM chips seem to get warmer than normal. It could also be corrosion under the CPU or RAM chips. If voltages seem ok and no chips heat up you can put some flux under the RAM and CPU and give them some heat, 150C do NOT fully reflow, just some heat.

 

[Rford]

At L7430 I have 0 volts... Probed around and am having trouble figuring out where in circuit the problem lies. Voltage drop is .15... not sure if this is low.

 

[larossmann]

Measure voltage on pins 16 and 17 of U7400 while the machine is on, and have eyes opened for burned things and corrosion.

 

[dukefawks]

This is strange... U7400 is tied into the ALL_SYS_PWRGD bus so that should not come high and the machine would not even beep. Are you sure you have no voltage on L7430 when the machine is beeping?

 

[Rford]

pins read 3.3ea

 

[Rford]

well, like 140mv I did have to jumper around U7400 some burnt traces but they werent a big deal, just to their respective components.