Tantalum Popcorn - What to do (Was S-100 Bus Voltages)

From: Sellam Ismail <foo_at_siconic.com>
Date: Mon Jun 4 14:55:57 2001

On Mon, 4 Jun 2001, Edwin P. Groot wrote:

> Well, I plugged in the boards and powered up the computer, and
> promptly powered it down after a few loud pops - D'Oh! Nothing was
> displayed on my teminal connected to the console serial line. The affected
> boards are the CPU board and a serial board - some tantalum capacitors
> blew. I'm assuming they're tantalum caps- they're not electrolytic
> can-style, or ceramic disc-style, but look like a gob of shiny blue acrylic
> paint on two leads. The board marks which lead is +.
> Are these tantalum caps common enough to buy at the local electronics
> shop? We've got Radio Shack, but I heard they are overpriced. The caps to
> be replaced were in the uF range.
> BTW this is a complete system and the cards are arranged (from low
> slot # to high slot #): CPU, RAM, FD controller, Serial/Parallel,
> Terminator. Will check with documentation that RAM and ROM banks, and I/O
> is configured right once I get the boards fixed.

I had this experience before with a Sol-20. Aside from being loud and
smelly, the tantalum caps exploding really shouldn't hinder the operation
of the system. Tantalum caps on older systems like S-100's that haven't
been powered up in some time are prone to exploding.

If you have a problem it's most likely related to some other failure.
Perhaps you should check to make sure you have matching settings on
your serial port and terminal. Also, make sure your cable is the right
kind (straight through...NOT a "null-modem" cable).

Also, maybe your system is expecting a boot disk to do anything useful.
Did you notice if your drives are spinning when you fire it up?

Sellam Ismail Vintage Computer Festival
International Man of Intrigue and Danger http://www.vintage.org
Received on Mon Jun 04 2001 - 14:55:57 BST

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