[Coco] Seeking: ECB ROM chip

[Little John]

Roger,
I also ordered a tube of 68764's so I could get Rogelio an EPROM for his 
CoCo. I use the EMP-20 - I have several of them and the 01-29 family 
modules, so this thing let's me program just about anything. The cool thing 
about it is that I was able to use the NT driver to install it into Windows 
XP, even though it's a DOS-Based device. As long as the programmer software 
is running Full-Screen, the NT driver allows Windows XP to operate the 
programmer. I haven't tried it, but I'm relatively certain that it won't 
work with Vista or 7.
-JohnT-

----- Original Message ----- 
From: "Roger Merchberger" <zmerch-coco at 30below.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, November 23, 2010 11:51 PM
Subject: Re: [Coco] Seeking: ECB ROM chip


> On 11/23/2010 05:14 AM, Little John wrote:
>> ----- Original Message ----- From: "Rogelio Perea" <os9dude at gmail.com>
>>
>>> Recently restored a 26-3004A F board CoCo, machine came with Color
>>> Basic 1.2
>>> only.
>>>
>>> Looking for a 24 pin ECB ROM chip to upgrade the machine.
>
>> Rogelio,
>> I'm not sure where to find those 8K 24-pin motorola EPROMs, but the
>> TMS2564 claims to be compatible with it's 24-pin counterparts by
>> allowing the extra 4 pins to "overhang" the socket. I will examine the
>> datasheets in a bit to see if this is true - if it is, I could burn a
>> TMS2564 for you. -JohnT-
>
> If the 24-bit 8K EPROMs you speak of are model numbers MCM68764/68766, I 
> have some good news & bad news...
>
> Good news is:
>
> 1) I have what's commonly known as a "Metric Buttload" of them; I received 
> a bulk lot (I think ~15 kilograms would be considered bulk... ;-) ) on 
> ePay back when it was auctionweb...
>
> 2) I have a bulk eprom eraser that can erase 20+ chips at a time...
>
> 3) I have a programmer that can program these critters,
>
> 4) I'm not one to overcharge people because I have a lot of something 
> nobody wanted 15 years ago...
>
> Bad news is:
>
> 1) These were insurance ROMs for the Panasonic/Quasar HHC pocket 
> computers. As such, they're in specialized carriers... there's a 
> decoupling capacitor soldered directly to the power pins that would need 
> to be removed and the pins carefully unbent from around the carrier and 
> just as carefully straightened before they could be inserted into a 
> "normal" ROM socket.
>
> This is certainly possible, I've done it several times -- but it's a labor 
> of love, surely! For someone to extricate 2 or 3 chips isn't that bad, but 
> for me to extricate chips for lots (read: a couple) of people, I really 
> don't have that kind of time.
>
> 2) My eprom programmer only runs under DOS, I have no computers that 
> currently do. (I do have PC that will work, but getting DOS and XP to 
> dual-boot will be an "interesting" task to get working, and I still have 
> to figure out a decent "sneakernet" as my new PC has no floppy, but DOS 
> doesn't use USB devices without a *lot* of heartburn...
>
> 3) No such thing as a "rush order." ;-) The chips are in my 3rd floor 
> attic, and I may have time this weekend to go rummaging around & find 
> them, but prolly another week to get re-set up for erasing / burning / 
> etc, so a 2-3 week minimum ship time, give or take...
>
> I've offered custom programming for folks as I made an adapter (made by 
> wire wrapping the pins on 2 back-to-back wire wrap sockets) so I can 
> program the chips without removing them from the carrier. The adapter's 
> not 100% foolproof (as a fool built it to begin with, eh?) so people that 
> did want that option, I generally "sell one, send 3" that way if one of 
> the chips didn't program/verify right (about 5% of the time, a chip would 
> verify correctly but not be programmed correctly, haven't figured that one 
> out yet...) or if a leg did break during extrication, there would be a 
> "Plan B" (and C) available.
>
> Chips are cheap, the programming's pretty cheap, but if you do want me to 
> do the extrication, *then* it gets expensive... ;-)
>
> A word to the wise: A couple dental picks help a *lot* for unfolding the 
> chip pins from the carriers.
>
> Hope this helps!
> Roger "Merch" Merchberger
>
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