Aquarite 940 no lights no display

Dsinise

New member
Jul 29, 2020
1
shelton, CT
Hi My unit is not working at all, followed troubleshooting, have power to main board, Xfmr, diodes but there is no power on pins 2 and 4 or 1 and 3 going to the display board. Would it be the main board that is bad? No visible damage to either board. Thanks for your help.
 

C0d3Sp4c3

Well-known member
Dec 10, 2018
99
NorCal
Based on the above troubleshooting, I suspect the 5vdc is missing. Are you comfortable performing the 3 point test?
You did not mention your pcb sw rev! Therefore I am presenting you with the below images and you choose the one that resembles your pcb.
You may want to remove the display bd to get a clear view of TP-14. Observe caution; insulate the tip of the red test lead with electrical tape leaving only the pointed tip exposed to avoid causing a short circuit while measuring voltages. Place the black test lead to the Negative post (R15) throughout the duration of the test. Use a mini grabber or alligator clip if available.
Apply power to the swcg, set the voltmeter to measure DC voltage.
U13 & U14 test:
1. Test TP-13 for 5vdc, if ok proceed to the next step
2. Test TP-14 for 5vdc, if ok proceed to the next step. If zero volt, the U13 failed (highly possible).
3. Test the header Pin#4 for 5vdc, if ok the 5vdc supply is good. If zero volt, the U14 failed (not likely but possible)
Once you positively identified the failure, disconnect the power to the swcg. Set the voltmeter to measure "Resistance" (ohms).
Please provide TP14 and Pin#4 resistance reading in ohms to determine if no downstream components induced the failure.

For testing purposes, a switching diode like IN914 or IN4148 can be used to temporarily bypass either U13 or U14 or both. U13 & U14 Repair
r15x test point.jpgr159 test point.jpg