Thought I'd post this as a PSA as this caught me out big time today.
I was doing a simple fan swap on this unit (it had previously been fixed a few months ago for liquid damage) and this resulted in a dead machine. Or to be more precise it was power cycling. No schematics but most voltages stable (no Vcore of course) except there was a coil near the WIFI card cycling to 1.2V and shutting down. Soon realised this was caused by the IO board (GC-RP77IO) as disconnecting it allowed the machine to boot.
Now I had removed the entire board, rather than the heatsink assembly to do the fan change. The interconnect cables between the motherboard and IO board are rather stiff and the connectors are rather flimsy. There are locking catches on the connectors, and I noticed that one end of a connector had started to come apart. As I was buzzing it out, I realised that at one end of the connector that the first pin had bent inwards, shorting to the connector body. It was very easy to do in retrospect as I didn't even realise I had done it.
So be very freaking careful with these cables if you are working on this unit, as I couldn't locate anywhere to get them if you damage them. The fans can also be pulled apart to clean the brass bushing and put in some Singer oil. Left the originals in there as cleaning resolved the noise.
I was doing a simple fan swap on this unit (it had previously been fixed a few months ago for liquid damage) and this resulted in a dead machine. Or to be more precise it was power cycling. No schematics but most voltages stable (no Vcore of course) except there was a coil near the WIFI card cycling to 1.2V and shutting down. Soon realised this was caused by the IO board (GC-RP77IO) as disconnecting it allowed the machine to boot.
Now I had removed the entire board, rather than the heatsink assembly to do the fan change. The interconnect cables between the motherboard and IO board are rather stiff and the connectors are rather flimsy. There are locking catches on the connectors, and I noticed that one end of a connector had started to come apart. As I was buzzing it out, I realised that at one end of the connector that the first pin had bent inwards, shorting to the connector body. It was very easy to do in retrospect as I didn't even realise I had done it.
So be very freaking careful with these cables if you are working on this unit, as I couldn't locate anywhere to get them if you damage them. The fans can also be pulled apart to clean the brass bushing and put in some Singer oil. Left the originals in there as cleaning resolved the noise.
Attached Files