Re: VIC-20 "all games in one" cartridge update

From: Ethan Dicks (
Date: 2001-04-03 23:47:14

--- Marko_Mäkelä <> wrote:
> I've now almost designed the printed circuit board for the VIC-20 memory
> cartridge.  It'll have 4 chips on the top side: Am29LV160D (2MB Flash
> ROM), HM62256B (32kB SRAM), 74LVX245 (data bus buffer), and Lattice 2032
> programmable logic chip.  On the bottom side there are only two 74LVX245
> chips that buffer the address lines.

Sounds simple.
> My question is: how many people would be interested in this cartridge, and
> how many have the skills and equipment to (a) manufacture, and (b)
> assemble the printed circuit board? 

I could build one for myself, but I'm not sure about how much fun it would
be to build lots of them.  I farmed out the manufacture of the GG2 Bus+
board for quality reasons and _it_ was a through-hole board, no SMT.

> This will be a freeware product, but
> since I think that SMD chips and boards are difficult to handle without
> expensive equipment, it would be good to have the boards professionally
> produced somewhere.  If someone knows a cheap place for doing this (I
> think etching, drilling and coating with the "green paint" that resists
> solder would be enough), I would like to know.

For SMT boards, proper etching and solder mask (green paint) is essential.

If there is an edge connector, gold is recommended.  Companies price boards
on how many holes they have to plate through, how many square mm of copper
there is (determines how much etchant is consumed) and how many linear mm
of gold fingers there are.  Quantities also matter.  A $500 set-up fee is
ordinary, plus, for an oversized cart, I'd guess $10 / bare board raw costs,
plus parts plus (I'm guessing here) $5-$10 to solder it in short runs.

I have installed/deinstalled SMT before.  I would personally expect to spend
two to four hours assembling the board you have described.  Not cost effective
to make 100 that way.

I'm interested and I'm interested in helping.  I have two NTSC VICs.


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