Hello everyone
A friend gave me this Baykunl D80 DRO (Digital Readout) he uses for a lathe/milling machine. The LCD stopped working, shows no image or color whatsoever, but the backlight works.
When you power up, sometimes you can see a brief image but for like 1ms then it goes black. That kinda tells me the LCD is actually good and the issue lies elsewhere.
The board has:
After visual inspection, nothing looks blown up, nothing burned, no discoloration, all traces look fine. Checked caps and diodes and transistors, no evident shorts. It uses a 104-240VAC to 5VDC 3A SMPS, which is working. The voltage regulator is outputting 3.3VDC, at lower side of the PCB near the LCD flex connector there are 3 test points for -7VDC, 10VDC and 16VDC, which i assume come from the LCD boost converter, and they are present, so the power supplies aren't the problem. For the time being i'm powering the device directly with my lab bench supply instead of the device's SMPS.
I checked the board with a thermal camera while it was powered and nothing looks to be overheating. I checked the LCD controller, pins 93 to 96 which are clocks for LCD scan and V-sync/H-sync, and they are present so i guess it is working. Both micro-controller and LCD controller are oscillating at the correct frequency (8MHz and 10MHz) respectively. I checked all pins from the micro-controller and i read high and lows, but no clock or pulse waveform besides the XTAL waveform.
It has a 5V buzzer that beeps as soon as it is powered up. Not exactly sure what it implies as i can't find the exact manual for this device, i'm assuming it beeps because i don't have the connections for the XYZ axis rulers. I de soldered it because the beeping was driving me crazy.
The IN6RL SMD IC seems to be related to the LCD connector, de soldered it to check for shorts and it doesn't seem to be bad. Can't find any info about it online.
At this point i'm not sure what else to check, any chance the micro-controller is bad? What else can i check to make sure that's the problem? Any help would be appreciated.
Thanks in advance!
A friend gave me this Baykunl D80 DRO (Digital Readout) he uses for a lathe/milling machine. The LCD stopped working, shows no image or color whatsoever, but the backlight works.
When you power up, sometimes you can see a brief image but for like 1ms then it goes black. That kinda tells me the LCD is actually good and the issue lies elsewhere.
The board has:
- 1x ST STM32F103VET6 Micro-controller
- 1x RAIO RA8876LN4 LCD controller
- 1x Winbond W9864G6KH-6 SDRAM
- 1x Winbond W25Q128JV Serial Flash Memory
- 1x ATMEL ATMLH834 EEPROM
- 3x Texas Instruments HC14 Hex Inverters
- 1x AMS1117 3.3 Voltage Regulator
- 1x PHOI 5 pin SMD, which is apparently a Texas Instruments TPS61040 boost converter for LCD and white led applications.
- 1x IN6RL 5 pin SMD, marking unknown, can't find anything about this. It is related someway or another to the LCD flex connector connector.
After visual inspection, nothing looks blown up, nothing burned, no discoloration, all traces look fine. Checked caps and diodes and transistors, no evident shorts. It uses a 104-240VAC to 5VDC 3A SMPS, which is working. The voltage regulator is outputting 3.3VDC, at lower side of the PCB near the LCD flex connector there are 3 test points for -7VDC, 10VDC and 16VDC, which i assume come from the LCD boost converter, and they are present, so the power supplies aren't the problem. For the time being i'm powering the device directly with my lab bench supply instead of the device's SMPS.
I checked the board with a thermal camera while it was powered and nothing looks to be overheating. I checked the LCD controller, pins 93 to 96 which are clocks for LCD scan and V-sync/H-sync, and they are present so i guess it is working. Both micro-controller and LCD controller are oscillating at the correct frequency (8MHz and 10MHz) respectively. I checked all pins from the micro-controller and i read high and lows, but no clock or pulse waveform besides the XTAL waveform.
It has a 5V buzzer that beeps as soon as it is powered up. Not exactly sure what it implies as i can't find the exact manual for this device, i'm assuming it beeps because i don't have the connections for the XYZ axis rulers. I de soldered it because the beeping was driving me crazy.
The IN6RL SMD IC seems to be related to the LCD connector, de soldered it to check for shorts and it doesn't seem to be bad. Can't find any info about it online.
At this point i'm not sure what else to check, any chance the micro-controller is bad? What else can i check to make sure that's the problem? Any help would be appreciated.
Thanks in advance!
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