[Coco] No MPI - any suggestions?
gene.heskett at verizon.net
Fri Oct 5 07:53:24 EDT 2007
On Friday 05 October 2007, Bruce W. Calkins wrote:
>>> You have to tape over the CTS or SCS line on the cartridge -- the
>>> one that auto loads it (I don't recall which, but since you've been
>>> working on a proto board, you probably do) so the pak doesn't auto
>On my first CoCo 1 I cut the wire into the cartridge header and soldered a
>switch with wires in to control the auto-start.
>> I think in the short term cassette transfer is the way to go - via
>> soundblaster output of course. I'd imagine I could "CSAVEM" on the
>> emulator and "LOADM" at the same time on the real Coco?!? ...
>I have heard of trying that. I haven't heard any success storys, yet.
I too have heard of that but haven't tried it. If the tones are at the
correct freqs there is no reason it shouldn't be hundreds of times more
dependable than the average cassette player & tape combo ever was.
A story here. I've had several CCR-81's & never could make any of them work
dependably, seemingly it always took a virgin chicken sacrificed to make it
work one out of 10 times. KFC's stuff didn't seem to work, but then I think
its false advertising to call that stuff chicken anyway.
Finally, in '86 or '87, someone needed something I had, and I rigged the
cassette motor switch to my Sony metal tape deck, and made 3 or 4 copies of
it using that. Recording only one channel. It seemed to work and I sent it
off. NDI who I sent it to now of course, but I got a message back over
delphi a couple of weeks later that that tape was a loads perfectly the first
time everytime tape. Two secrets:
1. The CCR-81 and all its ilk all use 'dc bias' cuz its cheap, often saving
battery power by using a permanent magnet swung against the tape for erasure
when the record button is pushed. It also gives a signal to noise ratio
that's 30 db poorer than a decently designed 100 kilohertz sine wave bias and
erasure generator can do. IOW, its 1944 technology & the only thing missing
is the tape made of kraft paper.
2. because it uses only a small amount of the tapes magnetic ability, the
playback levels are at best only about 1/4 that of the properly designed
version. Given the loss in signal to noise, its usually shot noises from the
tape that messes up the recovery.
So feeding a coco from a decently composed output from a sound blaster card
should get you perfect transfers every time.
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
You should avoid hedging, at least that's what I think.
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