DEC 3000/600 Alphaserver problems

[Peter Coghlan]

On Wed, 12 Jan 2022 at 11:02:47 -0600 Jon Elson 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:
>>
>> http://www.beyondthepale.ie/cctech/p1010198.jpg
>
> 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 tried desoldering one from the middle of the picture using two
soldering irons - I'm not very good at this surface mounted stuff :-(
It came out ok though. I must have got lucky and picked a good one
because it measured 47uF in the capacitance section on my multimeter.

Regards,
Peter.