[Coco] Pretty new screen

[Bill]

WOW!! Here is something unusual. I tried today to check out the chips (all
soldered but two), and the only way I could see anything on the screen was
to tune to channel 2 (3 or 4 do not pick anything up). I still have the
screen pictured in the link I gave, but it will ONLY come in on channel 2.

The 2 socketed chips are the SN74LS785N hidden partially under the keyboard,
and the XC80652P (58C8444), just to the right of the RF output.

This is, of course, the 26-3127B Korean Coco2


> -----Original Message-----

> From: coco-bounces at maltedmedia.com [mailto:coco-

> bounces at maltedmedia.com] On Behalf Of afra at aurigae.demon.co.uk

> Sent: Thursday, March 05, 2009 11:58 AM

> To: coco at maltedmedia.com

> Subject: Re: [Coco] Pretty new screen

> 

> Which CoCo model is this ?

> 

> Whilst I agree with Robert who said that it would be impossible to

> tell for certain, the one time I have seen a pattern like that before

> from a Dragon, which is basically the same as the CoCo 1/2, the

> problem was the 74LS244 buffer chip that sits between the processor

> data bus and the RAM/VDG data bus. Said LS chip had died and no data

> was getting writen to the RAM, and so the VDG was just pulling out

> whatever default patern was there.

>