[Coco] CM-8 Service Manual

[camillus Blockx]

You may want to ask in sci.electronics.repair because there are a lot
of TV/monitor technicians there. I think I've read there that a
problem like this is in the horizontal deflection circuitry, possibly
the damper diode, which may be a separate device or built into the
horizontal output transistor.

On Tue, Jul 10, 2012 at 11:17 AM, Andrew <keeper63 at cox.net> wrote:

> Message: 7
>> Date: Mon, 09 Jul 2012 15:16:58 -0400
>> From: "tonym" <tonym at compusource.net>
>> Subject: Re: [Coco] CM-8 Service Manual
>> To: coco at maltedmedia.com
>> Message-ID: <201207091516356.SM1136011@**MAIL>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Haven't had luck finding someone who will look at it.
>> The guy I used to use closed up, and moved to Texas.
>>
>> Maybe a description might ring someone's bell as to what it is?
>> I can see the screen, but it's trapezoidal - narrower on top, about 2" of
>> black border on both sides on bottom, about 3" on both sides up top.
>> Screen is legible, just wierdly shaped, and packed to the middle. Kinda
>> reminds you of the old 80's driving video games, trying to do a perspective
>> view of
>> a road going into the distance.
>>
>> Roy is backed up with the VGA converters, and I can't get anyone to fix
>> it, and the 80col screens aren't really legible, especially as my eyes
>> aren't as good
>> as they were 25Y ago :) So, I got this nice, shiny, new SuperIDE and a
>> Sardis FDC and a repaired J&M FDC... and I can't use it.
>>
>> Ideas on what the issue might be?
>>
>> I have a referral, but they guy says he doesn't do monitors, because it's
>> impossible to get parts.
>> However, cracking this thing open last night, it's mostly discrete
>> components, not a bunch of proprietary parts.
>> Wonder if I shouldn't just swing by with it to see if he'll take a crack
>> at it if it's not proprietary stuff?
>>
>
> Tony,
>
> Can't really help you on the issue, but I was curious about the cord
> coming out of the -front- (bottom left corner) on the picture you posted...?
>
> ...and I must be getting old: I could've sworn my CoCo 3 always read
> "SUPER EXTENDED COLOR BASIC 2.0" without the floppy drive connected (but I
> don't mine set up right now to check); I just re-ran VCC and ejected the
> MPI, and it comes up "EXTENDED COLOR BASIC 2.0", so that must be right
> unless I'm going crazy, senile, or both...hmm.
>
> I've heard/read here (you might check this list's archives) that there did
> (at one time?) exist boards meant mainly for MAME emulation to convert
> certain signals to VGA (which you want) and/or composite (which you don't
> want); supposedly some were able to work with the CoCo 3's output (???). I
> looked on Ebay ("mame converter") and found some, but I don't know which,
> if any, would be possibly work. It might be something to look into, at
> least.
>
> I'd still put in for Roy's converter; I have one from one of the initial
> runs, and I liked it's output - well worth waiting for.
>
> Andrew L. Ayers
> Glendale, Arizona
>
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