Acer Aspire 8735G CPU Upgrade Led to Black Screen

Hi,

I upgraded my Acer Aspire 8735G 6502 from an Intel T6600 to the T9800 CPU yesterday. Everything was working fine before I installed the T9800. Afterwards, however, the blue power light and the volume lights will come on for a few seconds (then turn off then back on and stay on) but no Acer flash screen or POST - just black screen. No activity from the hard drive light. So far, I have reset the RAM, 240M graphics card, attempted to connect to VGA (failed) and, of course, put the T6600 back in.

Based on reading many posts the most likely solution is to reset the BIOS/CMOS. I have located what appears to be the CMOS battery ("FG 18L 1B") located under the fan. It has a black plastic ring which I have gently tried to pry, twist, and screw out to no avail. The technical manual gives no instruction on where or how to replace the CMOS battery (which is now about 4.5 years old). Can anyone confirm that this is the CMOS battery and, if so, how to remove it?

I think that it is unlikely that the MB or graphics card is fried. There is no sign of burning and, as I said, it has been working perfectly for 4.5 years before the CPU swap. Any ideas or suggestions?

THANKS IN ADVANCE!!!

SPECS & TROUBLESHOOTING

Windows 7 Home Premium 64 bit
Separate graphic card - nVidia M240; 1GB DDR3(OEM)
4GB Samsung 1033 DDR2 RAM (have swapped 1 bank at a time)
Intel Core 2 Duo T6600,2.2Ghz, 800Mhz FSB, 2MB Level 2 memory, 35W, tMax 100, released Q12009 upgraded to used
Intel Core 2 Duo T9800, 2.96Ghz, 1033 FSB, 6MB Level 2 memory, 35W, tMax 90, released Q42008; Arctic Silver 5 applied
Phoenix BIOS v1.04 dated 9/2009 installed; v1.07 latest (2010?) available; Acer does not list CPUs supported by BIOS version.
HDD 0 Samsung EVO PRO 128GB SSD; HDD 1 Western Digital Blue 500GB
Motherboard JV80 1033Mhz
Intel Chipset P45
All peripherals disconnected for troubleshooting

FWIW other than the black screen and the inability to locate/reset CMOS battery the only thing that stands out in my mind about this upgrade effort was the substanial dust removed from the INSIDE cooling fins next to the fan. I didn't know dust would accumulate in an area that was only accessible by removing the fan from the heatpipe/heatsink/fan component.

 

cmospwd.exe /k with old cpu, then replace cpu.

 

Thanks for the reply, Flashin. The machine will not boot to a USB DOS bootable drive or a LINUX bootable CD. Assuming I can eventually boot to DOS, does cmospwd.exe clear ENTIRE (i.e., set to default) cmos or just password, time, and date?

I'm of the opinion that the item referred to above (silver circle on MB labeled FG, 18L 1B, 4Oms 2W, - +) is not a battery. I've read that many Acer laptop MBs use CR2032 batteries and this item is not a common cell battery.

Can ANYONE confirm that the Acer Aspire 8735G-6502 with motherboard JV 80 (23-40614-001) has a CMOS battery? Is it safe to assume that it is on the keyboard side (i.e., side opposite RAM, CPU, video card)? If no battery, where is the CMOS jumper?

 

The Acer Aspire 8735 Service Manual refers to the CMOS battery as the RTC battery. It provides no information about this battery but instead suggests sending the laptop to Acer for repair. I am providing the information below as a courtesy for future reference.

I found the CMOS battery. On the Acer Aspire AS8735G-6502 (MB JV 80) It is located on the keyboard side of the MB to the left of the touch pad. The battery is a standard cr2032 retained by a plastic lip that is about as thick as a piece of paper. Care must be taken or you, like me, will break this plastic lip.

As I had no idea where this battery was located I removed the keyboard and sound bar cover. DO NOT remove these to access the CMOS battery. The keyboard ribbon is secured by a toothpick sized locking pin which is easily detached -- and difficult to reattach.

Unfortunately, resetting the CMOS did not resolve my problem. My best guess at this point is that the Phoenix BIOS is dead as described here or that some secret keyboard sequence coupled with renaming BIOS files is required as described in this YOUTUBE video. The YOUTUBE video has about 700k views so it appears that my experience is not unique.


BLACK SCREEN OF DEATH


The power button is illuminated, the fan works, and the CD-ROM shows signs of life. This lasts about 10 seconds whereupon the power shuts down for about 5 seconds before the power light and fan starts up again and stays on. This is when the Black Screen of Death appears.

A bootable LINUX CD that I've successfully used hundreds of times will not work. There is no POST or any opportunity to access the BIOS settings.

The 700k viewed YOUTUBE relates the above symptoms to the Acer Aspire One -- not for the 8735G. DOES ANYONE KNOW THE KEYBOARD COMBINATION AND/OR BIOS FILE RENAMING INFORMATION NEEDED TO REVIVE THE ACER ASPIRE 8735G-6502?

 

SwissyFX, remove old CMOS battery. Put old cpu, assemble cooling, don't forget to plug in cpu fan. Put new CMOS battery. Connect keyboard, sound, etc. you disconnected, double-check everything. Disconnect all hdds, leave only one ram module. Try to boot.
p.s. you performed all the actions with notebook battery and psu unplugged, right?

 

Flashin, yes all actions have been performed without battery, unplugged using old cpu. Thanks for the suggestions. I followed your instructions exactly but still no luck.

The only logical conclusion is that the CPU damaged the MB. This seems strange as the CPU has no bent pins, was installed with Arctic Silver 5 on a properly seated heat sink, and uses the same socket type as the old cpu.

I've wasted many hours creating bootable DOS CDs in an effort to flash the BIOS. I chose the CD drive over the USB port because the system appears to attempt to access it after hitting the power button.

The laptop has been used as a desktop replacement and as such has not been moved often nor has the screen seen much use (always use an external monitor). This explains the dust buildup described above which may have caused above average temperatures on the cpu and gpu. In an effort to rule out gpu damage I've connected the machine via HDMI to an external monitor. The Black Screen of Death looms there as well.

 

Is it possible that the motherboard doesn't support the T9800?
The motherboard could be limited to a FSB of 800 MhZ... and if it is, then I'm afraid it would NOT support 1066MhZ FSB (on which T9800 operates on).

I find it dubious the CPU would damage the motherboard (though not impossible).
I hadn't read the thread in detail, but you can try replacing the CPU with your old one and seeing whether the laptop boots up as usual.

If it doesn't, then its possible you might have damaged something while replacing the CPU (laptop disassembly can be tricky, even in cases where you only have a back panel to remove to reach all components).

 

Double post

 

Hi, Deks and thanks for your comments.

By the time I wrote the SPECS edit I had pulled an all-nighter so I wrote 1033Mhz instead of 1066Mhz. I checked the chipset and MB compatibility before purchasing the T9800. Because I could find no information from Acer regarding BIOS compatibility I read posts of other owners of my model to conclude that the T9800 should work. All troubleshooting after the initial failure of the T9800 installation has been with the old cpu,T6600. I'm highly confident that I didn't damage anything when I first installed the T9800. As described above, I'm still having difficulty flashing the BIOS.