Reporting back on the repair unit... R38 (220k) resistor had totally blown open circuit! Replacing it (simply used a 1/2-watt through-hole part soldered to the smd pads), then reflowing all the toasted solder joints on R52/R53/D13/D14, and making sure U6 pin6 was soldered nicely restored functionality. Also did the common fix of removing, cleaning socket, replacing the EEPROM chip. That was done after previously rebuilding the Power Supply section: Electrolytic caps (C40 : 1000uF/25V) and (C48, C58, C59 : 220uF/25V) Diodes (D11, D12 : 1N4002 Schottky) D16 (1N4729 3.6V 1-watt Zener) new diode raised about 1/2" off the PCB and tilted away from the 1000uF cap...so that it won't toast the nearby pads like before. Unit is happy again, as will be the customer. Cheers!
Awesome! Makes perfect sense why you were seeing the same symptom! R38 is right before R52 in the path to ADC. Glad you got it running again for your customer. Despite the video being poor quality (shaky, too long, etc. 😂) I hope it was still helpful to you - that's one of the main reasons I made this channel!
This is happening to one in our shop, will reflow the terrible looking solder joints in that U6 area and report back. Would have liked a more concise to-the-point video (like actually state the error and fix in first minute, rather than 7-8 minutes in) just for some constructive feedback for your channel. But thanks for the helpful upload nonetheless!
Thank you for the feedback! I apologize for that. I'm working on getting more concise and better at editing. I'll add timestamps to this one as well so watchers can sift through what they need. Let me know how you make out!
i have same problem but the led will blink all 4 of them if switch A is activated. i’ve been check the other switch was normal. the resistor was good and the U6 is good on the solder. Do you have resolution for this problem? thanks
hmm thats interesting. So you're saying that all 4 LEDs start blinking ONLY when you press switch A? Does that symptom change depending on what mode the DL4 is in? Does it do this in both loop and delay mode? Also, have you tried putting the unit into test mode and performing test 6 (the button test)? I would try that and see if it still is causing this symptom during the test. I wouldn't rule out U6 just yet. The switches also connect to U6 which is an ADC. If you need a copy of the schematic and instructions for test mode, let me know
Reporting back on the repair unit...
R38 (220k) resistor had totally blown open circuit! Replacing it (simply used a 1/2-watt through-hole part soldered to the smd pads), then reflowing all the toasted solder joints on R52/R53/D13/D14, and making sure U6 pin6 was soldered nicely restored functionality. Also did the common fix of removing, cleaning socket, replacing the EEPROM chip.
That was done after previously rebuilding the Power Supply section:
Electrolytic caps (C40 : 1000uF/25V) and (C48, C58, C59 : 220uF/25V)
Diodes (D11, D12 : 1N4002 Schottky)
D16 (1N4729 3.6V 1-watt Zener) new diode raised about 1/2" off the PCB and tilted away from the 1000uF cap...so that it won't toast the nearby pads like before.
Unit is happy again, as will be the customer. Cheers!
Awesome! Makes perfect sense why you were seeing the same symptom! R38 is right before R52 in the path to ADC. Glad you got it running again for your customer. Despite the video being poor quality (shaky, too long, etc. 😂) I hope it was still helpful to you - that's one of the main reasons I made this channel!
This is happening to one in our shop, will reflow the terrible looking solder joints in that U6 area and report back. Would have liked a more concise to-the-point video (like actually state the error and fix in first minute, rather than 7-8 minutes in) just for some constructive feedback for your channel. But thanks for the helpful upload nonetheless!
Thank you for the feedback! I apologize for that. I'm working on getting more concise and better at editing. I'll add timestamps to this one as well so watchers can sift through what they need. Let me know how you make out!
@@fmashockie great idea with a timestamp...when techs are looking for solutions online, every bit of saving time really helps!
i have same problem but the led will blink all 4 of them if switch A is activated. i’ve been check the other switch was normal. the resistor was good and the U6 is good on the solder. Do you have resolution for this problem? thanks
hmm thats interesting. So you're saying that all 4 LEDs start blinking ONLY when you press switch A? Does that symptom change depending on what mode the DL4 is in? Does it do this in both loop and delay mode? Also, have you tried putting the unit into test mode and performing test 6 (the button test)? I would try that and see if it still is causing this symptom during the test. I wouldn't rule out U6 just yet. The switches also connect to U6 which is an ADC. If you need a copy of the schematic and instructions for test mode, let me know