[WriteLog] RE: User Port appears to have destroyed a Dell Insprion8100

[George Johnson]

Barry et al,
Your experience plus the post from KK9A makes me wonder if there is an
electrical (not S/W) drive problem on those motherboard parallel ports.  The
interface you used to connect to the port could be loading the port more
than the "designer" had planned.  And it would be worth checking your
circuit to see if that might be the case.  Otherwise, a repeat performance
might occur and just the wrong time.  As I recall, those ports were
originally TTL compatible current sinking rather than current sourcing
ports.  Our interfaces typically draw current to operate the keying
transistor.  The "typical TTL load" does not.

I noted in KK9A's post that he used LPT2 (on the SIIG board) successfully;
not the Dell motherboard port.  Hmm...
A look at the size of the series resistor in the base of the keying
transistor will allow an estimate of the current drawn from the LPT port.
George .. W1ZT




----- Original Message ----- 
From: "Barry Merrill" <barry at mxg.com>
To: "Writelog at Contesting. Com" <writelog at contesting.com>
Sent: Tuesday, May 27, 2003 1:07 PM
Subject: [WriteLog] RE: User Port appears to have destroyed a Dell
Insprion8100


> This is an update to my April 5 posting of this same subject.
>
> When I reported to Dell Technical Support on that Saturday that the
> machine would not power up at all, instead of getting an expected RMA
> to return the 18-month-old notebook for repairs, Dell immediately sent
> me an Inspiron 8200 notebook (1.7GHz vs 700 MHz, bigger hard drive,
> with Windows/XP vice 2000!) that arrived on Wednesday morning!
>
> But before again trying UserPort and the LPT keying circuit and burning
> up the new 8200, I spent the last six weeks trying to get someone at
> Dell in technical support who understands their power systems that could
> discuss what might have happened, to no avail.  It turns out that the
> old machine I sent back is never going to be examined by anyone at Dell;
> it just goes to a warehouse, and my detailed note attached to the machine
> to request an explanation will never be answered; and my point-of-contact
> replacement-sending-guy could care less as to why it failed, since his
> job is only to get me the replacement machine.
>
> So yesterday I installed User Port software on the new Inspiron 8200,
> then plugged in the (same) LPT Keying Circuit, and it works perfectly!
>
>  I first went to Control Panel, System, LPT section, to see what IO
address
>  are used on this system, then started User Port, deleted all default
> addresses,
>  and typed in the 03xx-03yy range from the control panel.
>
> So I must now assume that there was some other defect in the Inspiron 8100
> hardware that caused that pop and smoke immediately after plugging in the
> LPT Keying circuit, after starting User Port, so I withdraw my accusation
> that it was User Port itself that caused the old machine to die, and I can
> now confirm, as have many others, that you can use LPT Keying with Windows
> XP
> and User Port software.
>
>
> Barry, W5GN