[Coco] 68764/68766 EPROMs

[Arthur Flexser]

P.S.  It is also possible to bypass the disk controller clearance problem
by having a 28-pin 2764 or 27128 EPROM in a 24-pin disk controller socket
with pins hanging off the end and other pins bent outward to not plug in,
hand-wiring a few connections between things.  Not pretty, but workable.

Art

On Mon, Sep 21, 2015 at 6:33 PM, Arthur Flexser <flexser at fiu.edu> wrote:

> There have been various such adapters in the CoCo and non-CoCo markets.  I
> sold one with ADOS for a time.  Cloud 9 sells a particularly low-profile
> one, though it is somewhat more expensive than those sold by others.  There
> is not quite enough clearance for most adapters in the Tandy disk
> controllers--some have tried cutting a hole in the plastic cover, or just
> living with the cover not quite being able to snap shut (the screw will
> keep the cover from coming off, and the controller can still be inserted in
> the cartridge slot.  Probably not great for the long haul to have pressure
> on the circuit board, though.)  The Disto controllers, with their sheet
> metal covers, have a bit more clearance.  The problem of clearance is
> greatly magnified if you want to piggyback a SmartWatch real-time clock
> underneath the Disk Basic ROM.  (I went with a cutting-a-hole-in-the-cover
> method there in my own CoCo system.)
>
> A consideration that also exists is that it may be harder to find an EPROM
> programmer capable of programming the 6876x series than for the 27xx EPROMs.
>
> Art
>
>
> On Mon, Sep 21, 2015 at 6:14 PM, Mark J. Blair <nf6x at nf6x.net> wrote:
>
>> Would it be more practical to make an adapter to plug in more common 27xx
>> series EPROMs? I don't recall how much physical clearance is in there.
>>
>> --
>> Mark J. Blair, NF6X <nf6x at nf6x.net>
>> http://www.nf6x.net/
>>
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco
>>
>
>