Identifying Machine for DEC Memory

[Rob Jarratt]

> -----Original Message-----
> From: Jon Elson <elson at pico-systems.com>
> Sent: 01 April 2020 16:32
> To: rob at jarratt.me.uk; Rob Jarratt <robert.jarratt at ntlworld.com>; General
> Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
> Subject: Re: Identifying Machine for DEC Memory
> 
> On 04/01/2020 02:08 AM, Rob Jarratt via cctalk wrote:
> > I mistakenly bought some memory thinking it was for a VAXstation 4000
VLC.
> > It turns out that it isn't. It physically fits a VAXstation 4000 Model
> > 60, but putting it in that machine the machine fails to power up. The
> > part number is 50-19464-02, and I am unable to identify what machine it
> works in.
> > Can anyone tell me where to find out?
> >
> Is it possible the board is defective?  Does it have tantalum capacitors?
A VERY
> well-known failure mechanism of these is that they will work fine for
years, but
> if left unpowered for about two years, they will fail to a shorted
condition when
> powered on again.
> 
> In surface mount style, they will be little yellowish blocks with a bar
engraved
> or printed on one end.
> Locating the one or two bad ones is an exercise in major frustration!
> 

It is entirely possible that they are defective. I tried using a DMM to
measure the resistance across each of the capacitors. None showed a short,
but it could be that I am unable to establish proper contact. I noticed some
suggestions that they may be for a DECstation, I will dig mine out and see
if they work there.

Thanks

Rob


> Jon