[Coco] Primer on burning EPROMS?

[David Ladd]

On Mon, Jan 26, 2015 at 9:13 PM, Rogelio Perea <os9dude at gmail.com> wrote:

> On Mon Jan 26 2015, Christopher Barnett Fox wrote:
>
> Wanted to try burning some EPROMs, so bought one of the inexpensive Chinese
> > TL866CS universal programmers off eBay, $39.99 shipped. Is there a primer
> > anywhere on what else I'll need hardware-wise (e.g., a good source for
> > compatible EPROMs, suitable cartridge interface, etc.), and information
> on
> > how to actually burn and test?
> >
> > For cartridge interface, I have an FD-501, an FD-502, and a Disto Mini
> > Controller 1.
> >
>
> The main thing while working with the CoCo is that all disk controllers
> from Tandy prior to the FD-502 have a 24 pin socket for the ROM, the chips
> that Tandy used are hard to find and if found, the programmer you have (and
> many other modern ones) will have a hard time working with those chips -
> bottom line you need to work with a 2764 28 pin EPROM, you can get those at
> Jameco (where I recently bought a couple for my ADOS explorations), other
> vendors should have them as well (Mouser, Digikey, Ebay).
>

​You should be able to also use the 28C64 chips as well yes?  For those
that don't want to get a eraser could use a EEPROM in its place?​



>
> The 2764 can be fitted into a 24 pin socket provided you run a couple of
> jumpers and modify a couple of traces on the controller board (from the
> earliest CoCo disk controller up to the FD-501); I do not have a Disto Mini
> Controller but I assume it already comes ready for a 28 pin ROM, your 2764
> should just be a drop in install.
>
> The 28 pin to 24 pin adapter you can find info on the web on how to do it,
> there is an outlet that sells a ready made adapters although these are
> built in such a way that when placed on the disk controller you won't be
> able to close the case - the whole setup grows beyond the maximum allowable
> height inside the closed controller shell. Cloud 9 used to sell low profile
> adapters, check with them for availability.
>
> Last but not least, hopefully you bought an EPROM eraser. You will need
> one! :-)
>
>
> -- RP
>
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