[Coco] Pardon me for asking...

[Dave Philipsen]

Yeah, the 68766 are really old tech EPROMs. I’ve got programmers that will do 25v but in the past I just used 2764 EPROMs since they were much easier to find and pretty easy to rig into a 24-pin socket. And they could be programmed with 21v programming voltage with later versions even as low as 12.5v. 

It’s true that you need to have ECB to get to DECB but I’m not sure it’s necessary to have CB 1.2


-Dave Philipsen

> On Dec 14, 2021, at 12:22 PM, Charles Hudson <charles484 at twc.com> wrote:
> 
> Well, the ROMs are another story, one where the tail wags the dog:  I have some other TRS hardware and a few years ago bought a Tandy Color Disk Drive thinking I could adapt it for use with a Model III.  Later I acquired a 26-3022 controller to drive it. Then I read that the controller needed 12VDC and that the CoCo 1 provided it, so I bought the CoCo.  It got damaged in shipping so I broke the seal and took it apart to repair the case.  While it was open I inventoried and found I had Color BASIC 1.1, no ECBASIC, and a 16k E board.  And video so shaky it makes you itchy just to look at it.  And the drive didn't respond.
> 
> I found I needed CB1.2 and ECB ROMs to talk to the drive.  No problem: I had EPROMS and EPROM burners, but then I found that the recommended EPROM, an MCM68766, required 25 VDC to program; a voltage my USB burners could not furnish.  I looked at adapter boards but decided against them because they interfered with the other components and prevented re-installation of the RF shield. I found a Needham's programmer on eBay but am still collecting the pieces for that, so I sent two blank ROMs to Cloud-9 for programming.
> 
> I still don't know if the damned TCDD is operational, but at least I have a CoCo to show for it, replete with 64K RAM and an Hitachi CPU.  Keyboard is funky and the video is awful but we'll get to that, I suppose..
> 
> -CH-
>>>>