Dying VaxStation 4000 VLC - help?

From: Mark Tapley <mtapley_at_swri.edu>
Date: Fri Nov 22 23:18:01 2002

>Not the resistor, but I bet that darn tantalum capacitor could. I still
>suspect that.

You were probably right all along. I found someone at work who deals with
SMD devices on a regular basis. He has a small-nozzle heat gun, and agreed
(next week, when he has some time) to try to pull and replace the cap. for
me. After his and Toth's warnings about my current soldering iron (and your
own recommendation on what would be better to use), I think I may wait for
him and watch over his shoulder when it happens.

>[1} Remove all the solder you can with a hot iron and braid. Then melt
>the remaining solder on one end and _carefully_ lift that end of the
>component a fraction -- don't damage the pad on the other end of the
>component. Then do the same at the other end. Repeat until it comes free.

I'll save this advice in case I get very impatient, though.

>Hmmm. Maybe the value is printed on the bottom side of the cap for some
>strange reason.... Anyway, it's probably not that critical -- see above.

It'd be true for *all* of the caps on that board. I'll see and report when
that cap. comes off, but I don't see why the square cross-section ones
would be that way.

>If those values are correct, then you'd expect 5*61900/(11500+61900)
>volts on the tap. Or around 4.2V. That's what you're getting when the
>machine works, isn't it? So the values might will be right.

That's what I see. But with components of resistance same order as my
voltmeter, I'm surprised to see that with any accuracy.

>Oh, try something between 1uF and 10uF to start with.

OK, will do. I may even ask friend at work to pull one of the other caps
and test it on a bridge, just so I know what the proper value is.
                                                                - Mark
Received on Fri Nov 22 2002 - 23:18:01 GMT