[Coco] Tandy CM-8 Monitor Viewable Size

[Ron]

Hi Gene,

I haven't cracked open the case to check any of the capacitors, but that 
may very well be the case.  The quality still appears to be OK (for a 
CM-8).  No picture skewing or jitter of any kind.

I still have an old NEC multi-sync monitor (much bigger) I had purchased 
from Dr. Marty Goodman many years ago.  It continues to work as well.

I see 2 CM-8 monitors showed up on eBay just recently for those who may 
be interested.

Thanks!

-Ron


On 8/18/2015 9:31 PM, Gene Heskett wrote:
> On Tuesday 18 August 2015 21:05:02 Ron wrote:
>
>> Hello,
>>
>> I have a Tandy CM-8 monitor that seems to be working fine, however,
>> the actual "viewable" area on the screen seems much smaller than it
>> could be as there is quite a bit of black border around the whole
>> picture.
>>
>> Is this normal for a CM-8 or is there an adjustment that can be made
>> (internally) to increase the picture size as there doesn't appear to
>> be user controls to do this?
>>
>> Thanks
>>
>> -Ron
>  From a C.E.T.:
>
> You may be able to widen it a bit, but that would probably wind up
> pushing it to let out more magic smoke.
>
> If you look its innards over, and know what an electrolytic capacitor is
> supposed to look like, I'd bet a Miller64 there's a dozen or so that are
> either dried out because the antifreeze has all leaked out, leaving a
> white residue where the leakage took place, or just as bad, the top has
> bulged and perhaps split at the scored lines in the alu top.  Those are
> there to prevent its blowing up like an M-80 if the ESR goes too high &
> it gets way too hot.
>
> Bulged/split tops, or evidence of leakage means it needs to be replaced.
>
> Replacements should have a very low ESR, and rated for 105C service.
> ESR=Equivalent Series Resistance.  Usually measured at 50 to 100 KHz, by
> a special meter few techs have as its around a $200 bill, and for new
> capacitors, s/b well under 1 ohm.
> Cheers, Gene Heskett