Hi Guys and Gals,
I recently bought a used DNS-320L to help automate my photo and video backups.
I'm getting quite the collection and after loosing some forever have become a little paranoid about loosing more.
it has 2 2Tb Seagate Barracuda drives installed in it that test fine.
It seemed to work ok at first but it seemed to be rather picky about starting up first time every time, often taking 4 or mores tries to get it to spin up the hard drives and continue to boot.
I decided to investigate and pulled the mainboard out for examination.
There are quite a few vacant pads on the PCB where electrolytic capacitors should go, like across the main power input 12 volts, and across the each drive's power inputs as well. 5 spots all up.
Capacitors like these are used to "buffer" the power supply rail against droops in voltage due to sudden current spikes, like when a hard disk spins up for example.
I surprised they were left out, but I guess its some kind of cost cutting measure.
I looked in my junk box and found new old stock surface mount 220uF 16 volt caps and installed them in all 5 places.
I imagine anything from around 100uF to 470uf at 16 or more volts would do, pending that they physically fit.
Tantalums would work too I'd say .
Just make sue to install them the right way around, or they'll go pop!
So far so good, the box starts up from cold every time, more testing is needed of course but so far its looking good!
I hope it helps someone else out there,
Regards from Australia,
Raff.