[Coco] An open letter to the coco community
CoCoList for Color Computer Enthusiasts
coco at maltedmedia.com
Wed May 7 21:36:09 EDT 2014
Friends,
I am writing this letter to address the problem of the cost
of producing my converter. Since I have retired I have the time
to accommodate everyone. Also my full pension kicked in this
month so I don't need the money.
The cost to build the units is approximately $120 USD.
Isn't that ridiculous? So this is my proposal. I am going
to ask $200 per unit for my converter to those who can EASILY
afford it. But if you can't, I will accept any amount you can
comfortably manage, even if is nothing. What is the reason
for this policy change? Because the old low frequency
CRT''s are disappearing fast. I have fixed enough of the older
TV's in my time to realize they have a fatal design flaw and
Gene can probably back me up on this. The deflection
yoke coils are driven by the horizontal and vertical oscillators
They are heavily stressed by high energy magnetic fields.
This causes excessive vibration and heat in the
coils. I have found that this combination carbonizes and
removes the enamel insulating the wire of the coils causing the coils
impedance and resistance components to drop which
overloads the H.O.T. (horizontal output transistor) leading
to catastrophic failure. If you just replace the H.O.T. it
immediately fails and usually you cant see the problem because
the damage occurs on the inside of the coil where it makes
sharp turns in direction. Since the TV is old good luck
finding another yoke coil which is a shame because the rest
of the unit is in pretty good shape for its age.
Soooo.......it is imperative something be done to address
this problem and I am in a unique position to invest the time
and up front money to make a modern LCD monitor available
to every CoCo enthusiast.
Now my converter isn't perfect. It actually does too good
of a job rendering the signal. There is broadband noise coming
out of the GIME chip. The green signal is perfect. The red
signal is slightly off and the pure blue signal is so out of line
as to make the text difficult to read. The old slow CRT's did
a lot of natural filtering and of course Radio Shack took full advantage
of this by ending development when it was just good enough for
the CM-8. I have addressed the problem somewhat by adding both
input and output low pass filters to the unit. Its not a perfect
solution but it does help a lot.
Anyway , I figure with the caliber of people in this group I will probably
break even or close to it.
I also figure I can turn out 3 units a week working at a leasurely
pace.
So there it is friends. My life's mission is set before me.
I probably won't get bored anytime soon. :)))
Roy
More information about the Coco
mailing list