Re: TI-H: SPinTerface build question
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Re: TI-H: SPinTerface build question
>Date: Thu, 14 Aug 1997 21:42:01 -0500 (CDT)
>From: Tony Do <tonyd@execpc.com>
>To: TI <ti-hardware@lists.ticalc.org>
>Subject: TI-H: SPinTerface build question
>
>Hi,
>
>I'm in the process of building a SPinTerface for my calc and am testing
it
>before I cut and glue it into the case...
>
>My only doubt so far is that I'm only getting ~4.4 volts through +5V
and
>GND (last two rows on the port.) Is this normal? I am using the 7805.
>
>Tony
>
This is probably a normal voltage from a 7805. I had some bad (Radio
Shack) advice about voltage regulators. The 7805 will work with most
devices, but some things like the amplifier in the speaker cart draw too
much power through the voltage regulator. The low voltage is from the
drop out. The better choice for the voltage regulator would be the
78L05. It's a lower power version that produces a better regulated 5v
supply. I have been informed of this problem andI'm ordering a bunch of
the lower power Regulators. I knew the devices were drawing more power
than they were supposed to, but i didn't realize it was the power
source, not the devices.
If you want it perfect, put the 78L05 in. It will do a much better job.
Infact, if you intend to use an expander cart, it may actualy be a good
idea, eventhough it shouldn't hurt.
Sorry, blame Radio Sh*t, I mean Shack.
Richard Piotter
e-mail: richfiles@hotmail.com
home page: <A
HREF="http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html">The
Richfiles</A>
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