Re: Tape port trouble on a PET 2001N

From: Marko Mäkelä (
Date: 2002-11-10 10:21:09

On Sat, Nov 09, 2002 at 12:13:22PM -0600, David Wood wrote:
> Does this occur when the PC is -and- is not hooked to the cn232?

I didn't ask, but I think yes, it occurs in both cases.  The device works
properly in port #2.  I haven't measured the current consumption of the
C2N232 lately, but I think it would be in the order of some tens of
milliamperes.  Connecting something to the RS-232 port shouldn't matter,
since all RS-232 contacts (except ground) are routed via a DS14C232CM or
MAX232CSE.  It could still be a ground loop, but the device does work
in the other port.

On Sun, Nov 10, 2002 at 12:44:21AM -0500, William Levak wrote:

> It sounds like you have a short on the cassette port.  Probably one
> of the transistors that drive the port (Q4, Q5, Q6), the voltage
> regulator (VR2), or capacitor (C70).  Since the operating conditions are
> different, a marginal component may behave differently.  
> There may also be a marginal short on the connector or circuit traces.
> Another, simpler  possibility is that the connector does not line up
> correctly with the card edge.

Thanks for the suggestions, I'll pass them on.  One thing that occurred to
me from the schematic diagram
are the cassette jumpers.  Could they have been set inappropriately?


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