[Soekris] strange 4801 console characters

James K. Lowden jklowden at schemamania.org
Sat Jun 2 16:23:54 UTC 2012


I have two 4801s both suddenly behaving strangely.  I wonder if it's
the power supply, or they're both fried.  

The BIOS startup screen displays correctly, and reports 9600 bps.  But
letters I type appear one of three ways:

1.  Doubled: hheelllloo
2.  Almost doubled: hxeellllo!
3.  Scrambled: many high-bit characters

Naturally I assumed something was wrong with the serial port settings
on the terminal emulator.  But I have been using the same script to
invoke the emulator for about 8 years, and I know cu(1) pretty well.  I
tried all speeds from 150-38400; only 9600 has any useful result.  I
also have two machines that run cu, and connected together they're able
to transmit clearly.  (That also confirms it's not a half-duplex local
echo error.)  So the terminal and cable are OK.  

I have two Soekris 4801s and two power supplies.  One power supply came
from Soekris maybe 7 years ago; the other is a "universal" laptop
power supply from Staples producing 16.5 volts (output of amps and watts
not stated).  

With the Soerkris power supply I get mostly behaviors 1 and 2 above on
both machines.  Attempts to type "show" fail repeatedly.  However, the
startup screen appears normal and the machine boots and runs almost
normally.  "Almost" because the drive misfires every few hours:

	/netbsd: geodeide0:0:0: bus-master DMA error: 
	missing interrupt, status=0x1

which is what led me to replace the drive with an upgraded 8 GB CF
card, which is what led me to try to upgrade the BIOS, which is why I
need the serial console to work!  :-) 

Once the machine boots, I cannot log in.  The username+password are
rejected, presumably because scrambled.  

This morning I hooked up the Staples power supply to the spare 4801.
It also displays normally at bootup, but echoed letters are scrambled.
Commands are recognized even though the echoed letters are wrong.  I
was able to "show", and even "download" was accepted.  However I was
not able to transfer b4801_133.bin because of CRC errors.  Not all that
surprising, given what we know.  

Suggestions?  Do I need a new power supply, or a new 4801?  

--jkl


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