What to do if the picture is distorted on Radio Shack TRS-80?
If your Radio Shack Desktop picture is distorted even after fine-tuning adjustments, and you lack a Spectrum Analyzer, consider replacing the modulator unit.
Why clock does not appear at TP2 on Radio Shack TRS-80 Desktop?
If the clock does not appear at TP2 on your Radio Shack Desktop, it might be a modulator issue. Check the +5 volts at pin 11 and the 3.579 MHz clock at pin 1 of MC1372.
What to do if Radio Shack Computer Hardware display is garbled?
If your Radio Shack Computer Hardware display is garbled, ensure the telephone handset is firmly seated in the rubber cushions and that the baud rate is correct (both local and remote computer systems must send data at the same rate, 300 baud or less). Also, check if the received signal is too weak or noisy. If the remote modem is in answer mode, pick up the handset and listen for a clean tone. If you hear additional tones, dialing pulses, static noise, or voice sounds, the data may be garbled; try re-placing the call.
How to fix READY LED if it is off on Radio Shack Computer Hardware?
If the READY LED is off on your Radio Shack Computer Hardware, first ensure the power is on and the handset is properly positioned in the rubber cushions with the cord toward the RS-232-C cable end. Verify that the mode switches are set correctly. When communicating with a time-share computer, the modem must be in Originate mode. When communicating with another TRS-80, the mode selection must be agreed upon before data transmission, with one modem in Answer mode and the other in Originate mode. For data communication, the duplex switch must be in either Full or Half position (not TEST). Finally, check if the modem at the other end is compatible with the TELEPHONE INTERFACE II according to its specifications.
Why does my Radio Shack Computer Hardware display double characters?
A double character display on your Radio Shack Computer Hardware might occur if the system is in half-duplex mode. If the remote computer echoes all characters, the TRS-80 system must be in full-duplex mode. If the communication system is half-duplex (no echo), either RS-232-C or TELEPHONE INTERFACE II (but not both) must be in half-duplex.
General| Release Year | 1977 |
|---|---|
| CPU | Zilog Z80 |
| CPU Speed | 1.77 MHz |
| RAM | 4 KB (expandable to 48 KB) |
| Model | TRS-80 |
| Display | Monochrome CRT |
| Display Resolution | 64 x 16 characters |
| Storage | Cassette tape (optional disk drive) |
| Operating System | TRS-80 Level I BASIC (Level II BASIC with ROM upgrade) |
| Ports | Cassette |
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