DEC 3000/600 Alphaserver problems

Peter Coghlan cctalk at
Wed Jan 12 13:30:58 CST 2022

On Wed, 12 Jan 2022 at 11:02:47 -0600 Jon Elson via cctalk wrote:
> On 1/11/22 5:17 PM, Peter Coghlan via cctalk wrote:
>> Thanks Jon.
>> Here is a badly focused picture of the suspect components:
> WOW, I don't know what those are!  They look like big 
> ceramic caps to me, but if they don't have any polarity 
> marking, then they can't be Tantalum.  Big multilayer 
> ceramics are prone to cracking due to board flexing, and 
> that can cause catastrophic failure, too.

Thanks again Jon.

They do have spikes of solder sticking out from the positive ends
which can be seen in the picture.  There are no circuit references on
the I/O board where the picture was taken.  However there are markings
on the system board including little + signs at the same ends as the
solder spikes on similar capacitors on that board.

I managed to desolder one of them from the middle of the picture using
two soldering irons.  I am not very good at this surface mount stuff :-(
It came out ok though.  I must have got lucky and picked a good one
because it measured 47uF on the capacitance range on my multimeter.


> Jon

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