replacing a dc005? (qbus chip)

[Ethan Dicks]

On 1/10/07, Brad Parker <brad at heeltoe.com> wrote:
> One of my rqdx3 boards suffered a trauma in a previous life and one of
> the "DC005" chips at the bottom cracked in half.  Needless to say the
> board does not work.

Ow!

> I removed the old chip, but what now?
>
> Does anyone have a spare DC005 or know of a suitable replacement?  I
> assume this is one of the magic DEC chips for qbus.

It is a DEC "magic Qbus chip".  We used to buy the DEC "Qbus Chip
Kit", but we did use the DC005 to talk to the bus (just not their DMA
chips).  If you needed some other Qbus spare, I would probably have
it, but we used all of our DC005s in our product.  I know some 3rd
party vendors used to use chips like the 72LS240 to interface to the
Qbus, but I doubt they are pin-compatible nor even function-compatible
with a DC005.  Of course a '240 won't have the same bus loading, etc.,
but for a single-backplane system, you'd probably never know the
difference.

> I suppose I could try extracting one from another board, but that is
> pretty painful... dips are easier to get out if you can snip their
> leads.

They are much easier to get out if you don't care about the board.

-ethan