User manual

ASURO - 28
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6. Error tracing
6.1. Failure of the RS232-IR-transceiver
6.1.1. Activated key and displayed symbol do not match
Calibrate Trimmer TR1 until activated key and displayed symbol do match.
6.1.2. The terminal program does not display any symbol
Has the timer-IC (IC1) been inserted and has it been inserted correctly polarized (the mark
must point to the three diodes) ? Take any infrared remote control of a HIFI- or video-equipment
(videorecorder, TV, etc) and point it to the IR-transceiver, pressing a few keys. If the terminal
program displays irregular symbols, the receiver (IC2, R3, C4, D4, T1) is operating. All other parts
have to be checked.
6.1.3. Still not working
Check all parts for correct polarisation and correct value (see  g.
4.1). Check soldering
connections for short circuits and bad soldering. Has a soldering pad been disrupted ?
If all checks have been made without results, the bad part has to be traced with the help of the
schematic (see Appendix B) and an adequate measurement device (multimeter or oscilloscope).
(In most cases one of the components IC1, IC2, Q1, D4 may have been damaged).
6.2. USB-infrared-tranceiver does not work
6.2.1 WINDOWS
Check if the drivers are installed correctly and if the correct com port is selected.
6.2.2 LINUX
Disconnect the USB transceiver... wait a minute and connect it again, this may solve the problem.
An other option is to install a new kernel
6.3. Back-LEDs (D15,D16) do not glow at startup!
6.3.1. None of both back-LEDs is glowing
Please look very carefully in a darkened room. If no light can be seen, check the following steps:
- Have 4 batteries been inserted, are the batteries fresh or have they been charged anew?
- Did you connect the battery-cable correctly ? (red to Bat+ and black to Bat-)
- Has Diode D9 (1N4001) been inserted with correct polarity?
- Did you use the correct value for R22? 470Ω (yellow, violet, brown, gold)
- Also check for R18, R19, R20, R21:
4,7KΩ (yellow, violet, red, gold)
1KΩ (brown, black, red, gold)
Electronics