What Can Cause Topside Panel Blank?

[yingtixu]

Recently I purchased a used Balboa 2000 spa with the controller # 52761-01 ( the PCB # is 52762). The seller told me the spa runs but the heater does not work. After I made the power connection and turned the spa on, I found the topeside panel showed 8888 and then within a few seconds it turned to blank . The background light of the panel is on. The SPA runs on the economic mode at least once a day. However, SPA can't be operated intentionally and it can neither be checked out because the panel is not displaying. So the first step of my repair is to make the panel work so I can get all the message about the unit from the panel. But I have not being successful on it so far. Hope someone can help me. Here are all the information I have observed and measured:

Current Operation Status: When the panel plug is put in the top socket, the spa does not run, but the unit seems cycling because I can hear the click sound and the economic mode runs at least once a day. When the economic mode starts, the spa runs first on the high speed for about one min. and them on the slow speed for about 2-3 min. The blower is also working during running of the mode.

Panel Plug Connections: I have cleaned the phone plug of the panel wire. Since the panel shows digits 8888 at first a few senconds after the power is on and the panel background light is on, so I assume the plug is connected to PCB in some degree.

Voltages on PCB:

1. Whether spa is running or not, the volts between two hot input terminals (black and red) is 240, between black and white is 240, and between red to white is 0.

2. When spa is not running, J20 (pump2-low), J13 (pump2-high), j28 (pump1-low), j29 (pump1-high), J14 (Ozone), J41, and J27 are all zero volt. When spa runs on slow speed, J20 (pump2-low), J29 (pump1-low), and J14 (ozone) are changed to 240v, and J13 (pump2-high), J29 (pump1-high), J41, and J27 are stay on 0 volt.

3. Whether spa is running or not, all fuses are meastured 240v.

4. Thansformer: Whether spa is running or not, all 4 solder spots which are visible on one side of the transformer on PCB, to neutral are 0v. (This might be the problem!)

Heater: The resistance between the two terminals is 10 ohms, and between each terminal to ground is 0 ohms.

When spa is not running, the volts between two terminals is 0v, between each terminal to neutral is 0v, and between each terminal to ground is 120v. When spa is running on low-speed, the volt between two terminals is changed to 240v, between the left side terminal to neutral is 0v, and between the right side terminal to neutral is changed to 240v. The volt between each terminal to ground is a little less than 120v.

Hope this time I have provided more accurate information, and I desperately need anyone to help. Thanks, Victor