Only HDD 1 & 2 power up


Ammonia
 Share

5 5

Recommended Posts

My Helios64 was running fine with 5 HDDs for a couple of weeks, then I suddenly couldn't access the shares anymore and I noticed only two HDDs were running (the rest having no indicator lights).

 

HDD slot 3, 4 and 5 appears "dead", no power up on boot, no indicator lights. I have checked both +12V and +5V rails and they are present, everything is plugged in. I can move the HDDs from slot 3, 4 and 5 to slot 1 and 2 and they will power up just fine. The hard drives also work in other machines.

 

I'm a bit lost as to what might be wrong, any ideas?

 

 

Link to post
Share on other sites

Donate and support the project!

I checked the +12V and +5V on the 15-pin power connector directly (that the hard drives plug into). All measure fine, but of course that is without a load connected.

 

In my case only the two hard drives connected to 12V HDD Rail B start up. Something wrong with the power staggering approach in bootloader?

 

dmesg output immediately after booting:

 

ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)

ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)

ata3: SATA link down (SStatus 0 SControl 300)

ata4: SATA link down (SStatus 0 SControl 300)

ata5: SATA link down (SStatus 0 SControl 300)

Link to post
Share on other sites

I did some more troubleshooting. The +5V HDD Rail A is present when no hard drives are connected, but drops to 0.8 V when the the drives are connected. It looks like the rail is enabled by a TDM3421 P-channel MOSFET?

 

Measuring the MOSFET with no load:

Gate = 3V, Source = 5V, Drain = 5V.

 

With the rail loaded:

Gate = 3V, Source = 5V, Drain = 0.85V

 

Is it implemented as a high-side switch? Any plans of releasing the schematic for the Helios64? I'm no electrical engineer but I suspect the MOSFET is faulty?

Link to post
Share on other sites

2 hours ago, gprovost said:

@Ammonia Have you managed to fix it yourself ? If not please contact us to support@kobol.io

 

I ordered a replacement MOSFET (same model), including a drop-in replacement from vishay with better power ratings (just in case it should happen again). Unfortunately shipping is taking longer than it should. I temporarily bypassed the MOSFET to get all the hard drives to boot up so I could transfer the more important data. I was hoping fixing it would be faster than receiving a replacement board - and for me dealing with UPS is playing Russian roulette. Fixing it by replacing a 13-14 cent component is the better option for us both. Hopefully I won't ruin the board in the process!

Link to post
Share on other sites

16 hours ago, gprovost said:

@Ammonia Nice job :-) What was the casualties ?

Should have told you that better unsolder first the Molex connectors since they easily start to melt when expose to close to heatgun.

 

R144 and C129 disappeared into the 4th dimensions, as SMDs of that size has a tendency to do. I protected the connectors and the rest with some kapton tape, that worked well. I will put replacements of those passives back after the holidays, just need to get myself a smaller tip for the iron. Doubt that missing soft start will be an issue though.

Link to post
Share on other sites

 Share

5 5