Re: [cosmacelf] Notes on MSI/88e Deconstruction
- Why not just solder the chip to a machine tool pin socket, and insert that
into another socket? (You *are* using machine tool pin sockets, right?
Anything else would be sub-standard!)
On Thursday 05 June 2003 17:10 pm, Mark Graybill wrote:
> Well, I pulled the ROM out of the MSI/88e today and wasn't able to read it
> with any of the 8Kx8 formats my ROM burner will read. The address and data
> lines look like a standard layout, but I haven't traced the select logic
> on the board yet to see what's going on. It's pretty easy to follow,
> though, since it's on the same board as the CPU and right next to it.
> The chip appears to be a Signetics 27884, which I don't have data for. But
> since the address and data lines looked standard, I thought I'd drop it in
> the reader and give it a try. If anyone's got a suggestion for reading
> this chip, let me know. If I can figure out the select logic I may put
> together an adapter to allow the reader to treat it as a 2764.
> In the meanwhile, I'm going to check out the 1802 I pulled as well. If
> time permits around my other projects, I'll try to do a quick free-run test
> with it this afternoon.
> A note to people thinking about using the MSI/88e for parts--the
> assemblers were very good about trimming the leads on the chips, so the
> leads are too short for many types of sockets and for breadboards. Low
> profile sockets will hold onto them pretty well, but you may want to
> include something to hold the chip down to keep it from lifting out, even
> then. If you're doing wire wrap you'd probably have to put the chip in a
> low-profile socket then put that socket in a wire wrap socket, and have
> something to hold the chip down since if the socket flexes or gets jarred
> sharply the chip can fall out.
> Of course, if you're confident enough to solder the chip straight into the
> circuit, this won't be a problem. Presently I'm not that confident. (Now
> where did I put that lead stretcher?)
> -Mark G.
> Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
> Wiki/FAQ at http://1802.bitting.com/
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- --- In email@example.com, "J.C. Wren" <jcwren@j...> wrote:
> Why not just solder the chip to a machine tool pin socket, andFor some parts, that's not cost-effective. Fortunately for me, I
> insert that into another socket?
picked up a few tubes of 14-pin machine-pin sockets at the Dayton
Hamvention last month for $1/tube (that's $0.04/socket)... I
probably should have bought the entire bin! Normally, they are
several times more expensive than that. New CMOS parts are
frequently cheaper, CPUs, RAM and odd I/O chips notwithstanding.
> (You *are* using machine tool pin sockets, right?Absolutely. Somewhere in the attic, I have a couple of cubic
> Anything else would be sub-standard!)
feet of machine-pin WW sockets. All I need is a good source
of WW wire and I'm all set.