MicroVAX 2000 memory cards with bad caps

[leegleason]

Today I had a MVAX2000 that wouldn't start - failed test B, which is memory. I opened it up and had a look at the 4 MB memory card. It has three of what look like SMD bypass capacitors that look...burned. As well, some things around them look corroded. Do SMD caps leak like normal electrolytics? In any case, I had a spare card. As I put it in, I noticed its caps looked deteriorated as well, with some surrounding corrosion as well, although not as bad as the first card If there are any MVXA2000 fans left out there, anyone else seen this problem before?

 

[Schroeder]

Is it those black ones, often with a light red mark? If so, they look like that. Don't know if they did look like this when they where brand new. I usually replace them. I guess they loose their coating. Just a guess.

 

[leegleason]

Is it those black ones, often with a light red mark? If so, they look like that. Don't know if they did look like this when they where brand new. I usually replace them. I guess they loose their coating. Just a guess.

Well, there's two big ones, more grey than black, and one smaller grey one with a little read dot. I don't have any SMD gear or experience (or desire to gain either), so I just popped them off with a screwdriver. There was more corrosion at the attachment points. I figured, they look like bypasses, so I decided to Madman Muntz it, and just put it baclk in without trying to replace them. It fired right up, seems to be working fine. For a vintage collectible, I'll just live with a slightly reduced noise margin in their absence.