Hello.
I recently obtained a broken Shuttle ST61G4 system complete, ready to run even down to the legit XP Pro COA.
It's a very pretty little computer with a mirrored front, built-in camera card reader, Firewire, front audio ports and so forth. Cute, even.
It just didn't boot. Powers on, Lights on, fans on.
No Video, no disk activity.
Tried a known good PSU- no luck. The PSU and board are entirely populated with OST in apparent good condition.
Pulled out the board, checked the caps with an oscilloscope with the power on- 1.4v a little lumpy with ripple at 40mv ( I think)
I just happened to check the CMOS battery at this point- DEAD.
Pop in a new 2032 CMOS battery- Surprise! The system works great! It seems that the ATI RS300 chipset requires a live CMOS battery in order to boot! Oh my.... I wonder how many systems have been discarded because of a tiny watch battery gone dead?
So I went ahead and recapped it anyhow with Rubycon MCZ on the mainboard and UCC KY and KZJ in the PSU. The PSU had non-standard 10mm 2200uf/16v in it which measured at 2000uf. My KZJ replacements were 1800/16 that measured 1900uf.
After recap, the 1.4v at the caps on the mainboard was flat. No trace of lumpyness. Probably if I change the v/div I could find some.
It just goes to show....
Don't assume anything. Even though most computers start OK with a dead CMOS battery, some don't. The previous owner could have saved buying a new system with the purchase of a tiny battery at Walgreens. The system had been disassembled and thoroughly cleaned before I got it, so it's likely that someone had tried to repair it and gave up.
Due to its dimunative size and total cuteness, I'll probably have to find a place for this thing somewhere. Maybe use it as a dedicated Windows box so I don't have to Boot Camp this Mac Pro when I want Windows.
Have Fun!
Keri
I wish that I had an ESR meter when I had this thing apart. Still, I did save the caps so that I can check them later. Most of the OST caps I pulled were in spec for uF except for the two non-standard ones in the PSU. It'll be interesting to see where the ESR falls.
I recently obtained a broken Shuttle ST61G4 system complete, ready to run even down to the legit XP Pro COA.
It's a very pretty little computer with a mirrored front, built-in camera card reader, Firewire, front audio ports and so forth. Cute, even.
It just didn't boot. Powers on, Lights on, fans on.
No Video, no disk activity.
Tried a known good PSU- no luck. The PSU and board are entirely populated with OST in apparent good condition.
Pulled out the board, checked the caps with an oscilloscope with the power on- 1.4v a little lumpy with ripple at 40mv ( I think)
I just happened to check the CMOS battery at this point- DEAD.
Pop in a new 2032 CMOS battery- Surprise! The system works great! It seems that the ATI RS300 chipset requires a live CMOS battery in order to boot! Oh my.... I wonder how many systems have been discarded because of a tiny watch battery gone dead?
So I went ahead and recapped it anyhow with Rubycon MCZ on the mainboard and UCC KY and KZJ in the PSU. The PSU had non-standard 10mm 2200uf/16v in it which measured at 2000uf. My KZJ replacements were 1800/16 that measured 1900uf.
After recap, the 1.4v at the caps on the mainboard was flat. No trace of lumpyness. Probably if I change the v/div I could find some.
It just goes to show....
Don't assume anything. Even though most computers start OK with a dead CMOS battery, some don't. The previous owner could have saved buying a new system with the purchase of a tiny battery at Walgreens. The system had been disassembled and thoroughly cleaned before I got it, so it's likely that someone had tried to repair it and gave up.
Due to its dimunative size and total cuteness, I'll probably have to find a place for this thing somewhere. Maybe use it as a dedicated Windows box so I don't have to Boot Camp this Mac Pro when I want Windows.
Have Fun!
Keri
I wish that I had an ESR meter when I had this thing apart. Still, I did save the caps so that I can check them later. Most of the OST caps I pulled were in spec for uF except for the two non-standard ones in the PSU. It'll be interesting to see where the ESR falls.
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