Even easier, in BASIC open the com port & set up a loop which sends 0xAA each time through the loop....
On 8/2/17, Kurt McCullum <kurt.mccul...@att.net> wrote: > Thanks John, > > That sounds doable for me. At least I'll be able to find the culprit. At 300 > baud I should be able to pick up a signal. > > Kurt > > -----Original Message----- > From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of John > Gardner > Sent: Wednesday, August 02, 2017 9:24 AM > To: m...@bitchin100.com > Subject: Re: [M100] Model 100 serial port > > ...the problem is somewhere between the db25 and the UART... > > Most likely. I'm no great troubleshooter, but if I may... > > Set up a test file which contains a long series of 0xAAs, as in > > 10101010... > > Send the file at a baud rate which is easy for you to see with > > whatever you've got for test equipment. > > While the file is being sent, look for the signal. When you find it, > > the fault is between that point & the DB25. I expect the problem > > is either a PCB trace, solder joint, a defective buffer, or the DB25 > > connector itself (It happens...). > > There's also a small possibility that the UART is at fault, but not > likely. > > I'd be interested to hear what you find. > > > > > > On 8/2/17, John R. Hogerhuis <jho...@pobox.com> wrote: >> Well the good news is the problem is somewhere between the db25 and >> the UART :-) >> >> -- John. >> > >
