| Electronics > Repair |
| What more i can do? |
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| asis:
Clarify me more to it, How to provide more Voltages, is there any diagram? [/quote] The idea is simple. If you have a LAB PSU with the ability to set the output voltage >/= +5.5V and the output current, about - 0.5~1A, just connect GND and +5.5V to the PCB power connector, which is already powered by a standard power source. Connecting two sources with the same or close voltage values in parallel should not cause anything fatal. You can connect the LAB PSU through a suitable diode. The goal is to raise the voltage of the common +5V bus and see how the device reacts using the "RESET button". During the experiment, you can disconnect and connect the LAB PSU. - The +/- 12V voltages are probably used only to power the RS232 IC19/ IC20/ IC79 (GD75232D) and RS485/422 IC81 (SN751177N) drivers. Check it out. |
| 222Lab_Test222:
--- Quote from: asis on December 09, 2024, 01:42:54 am ---Hi, 1. Vin LT1587CT allows +7V and probably the Vin circuit is connected to the +5V bus (check this). 2. The Adjustable resistor (varactor) is a weak point, because over time, its carbon layer has the property of losing its stability. --- End quote --- I install a new LT11587CT couple of weeks ago so its good.. |
| 222Lab_Test222:
--- Quote from: asis on December 09, 2024, 03:00:11 am --- If you have a LAB PSU with the ability to set the output voltage >/= +5.5V and the output current, about - 0.5~1A, just connect GND and +5.5V to the PCB power connector, which is already powered by a standard power source. Connecting two sources with the same or close voltage values in parallel should not cause anything fatal. You can connect the LAB PSU through a suitable diode. --- End quote --- I have 2 PSU.. CKT like this is good? Whats the didode requirement? |
| 222Lab_Test222:
--- Quote from: Harry_22 on December 09, 2024, 12:47:03 am --- Could you measure both Vout by multimeter on working and not working. Also please measure +5volts at the same EPROM pins on both. --- End quote --- Working Board -Vout 3.57V -EPROM High 5V -EPROM Low 5V Non Working Board -Vout 3.61V -EPROM High 5V -EPROM Low 5V |
| Harry_22:
And 5.00 ? Reduce 3.61 up to 3.45 |
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