Remote Processing RPC-52 - Manual (Page 9)

CHAPTER 2 SETUP AND OPERATION
Page 7
TROUBLESHOOTING
You would probably turn to this section because you
could not get the sign on message. If you are getting a
sign on message but can' t enter characters, then read the
end of this section. The following are troubleshooting
hints when you can' t get anything.
1. Check the power source. If it is below 4.65 volts at
the input pow er ter minal, the RPC -52 will re set.
Power is 5 ±0.25 volts. Make sure it is a clean 5
volt source . If it dips in term ittently to 4. 65 volts
(due to switching noise or ripple), the card will reset
for about 100 ms. If the noise is frequent enough,
the card will be in per manen t reset. Check U16, pin
15. If it is low (about 0 v olts), the n it is in reset.
This line should be high (about + 5 volts).
2. Check the COM 0 port (J3). Rem ove the connector
from COM 0. R efer to the outline dra wing ear lier in
this chapter. Connect an oscilloscope (preferred) or
a voltmete r to pin 3 (T xd) and gr ound. Pin 3 should
be -6 volts or more negative. (Pin 1 is designated
by the
w symbol on the connecto r. Pin 3 is next to
it, nearer the key opening.) If you have -6 volts or
more, press the reset switch. If you have a scope
attached, you should see a burst of activity. With a
volt meter, you should see a change in voltage.
Using a F luke 8060A set to measu re AC , yo u should
see a momentary reading above 2 volts. Press reset
severa l times to m ake sure it captures it.
3. Install the cable and make sure the voltages and
output activity are still there. Output is from pin 3
on the VTC-9F. If not, check to make sure
something is not shorting th e output.
4. Check the serial pa ram eters on y our P C or termin al.
They should be set to:
9600 baud, no parity, 8 data bits, 1 stop
5. If you are receiving a sign on me ssage but not ab le
to enter characters, check U10, pin 5 for at least -6
v o lt s. W h e n i t i s n e ar 0 vo lt s, t h e t er m i na l o r P C ' s
Tx line is not connected to the card. When you
press a ch aracter on the term inal or P C, you should
see the voltage go positive.
If all of this fails, call technical support listed at the front
of the book.