SU/SD Board Isolation

Subject: Purpose: Isolation of SU and SD boards from the SC board. Symptoms such as shutdown followed by a 7-blink code may be caused by a circuit failure located on any of the SU, SD, or SC boards. This procedure helps pinpoint the location of the failedboard. TH-42PX80U, TH-50PX80U, TH-42PZ80U, TH-46PZ80U, TH50PZ80U, TH-42PZ85U, TH-46PZ85U, TH-50PZ85U, TH42PZ800U, TH-46PZ800U Not yet confirmed in TH-50PZ800U, TH-58PZ800U, TH46PZ850U, TH-50PZ850U, TH-58PZ850U, and TH-65PZ850U. Unlike previous models of Panasonic Plasma TVs, the 2008 models listed above are designed not to turn-on if either of the SU and SD boards is disconnected. Disconnecting either causes the unit to shutdown and the power LED to blink 7 times. Unplugging any of the connectors SC41/SU41, SU11/SD11, and SC42/SD42, opens the interlocked connection between VF_GND and CHA on the SC board. This floats point CHA, triggering shutdown, refer to figures 1 and 2.

Models:

Figure 1

Figure 2

Precautions:
Disconnect AC Power prior to making or removing any connections! Do not let the TV run for more than 30 seconds while connectors or boards are disconnected. Floating ground and chassis ground are different! Avoid connecting VF Ground (Floating ground) to chassis ground, as this will cause severe damage to the unit. On the SU and SD boards, observe carefully and differentiate between the locations of board mounting screws (Chassis ground) and locations of screws connected to floating ground. 1- Disconnect connectors SC41/SU41, SU11/SD11 from the SU board Isolating the SU board does not require the removal of its mounting screws. 2- Place a jumper between VF Ground (labeled H.V. DANGER) on the SU board or SD board and coil L801 on the SC board, see figure 4. The jumper can be connected to the floating ground screws on the SU board, which are located above and below connector SU41, see figure 3. Note: On most TVs L801 is located on the lower left hand corner of the SC board but on some UA ending models (TH-42PZ85UA, TH50PZ80UA, etc), L801 is located in a different location. See figure 5 to see the location of L801. Caution: Before turning the unit on, confirm that the jumper is not connected to a chassis ground screw, as this will cause severe damage to the unit. Confirm proper connection by measuring continuity between floating ground and chassis ground. The resistance should be in the kilo-ohms range. 1. Disconnect connectors SC42/SD42, SD11/SU11, and SD46 from the SD board Isolating the SD board does not require the removal of its mounting screws. 2. Place a jumper between VF Ground (labeled H.V. DANGER) on the SU board or SD board and coil L801 on the SC board, see figure 4. The jumper can be connected to the floating ground screws on the SD board, which are located above and below connector SD42, see figure 3. Caution: Before turning the unit on, confirm that the jumper is not connected to a chassis ground screw, as this will cause severe damage to the unit. Confirm proper connection by measuring continuity between floating ground and chassis ground. The resistance should be in the kilo-ohms range.
Procedure to isolate the SU board.
Procedure to isolate the SD board.

Figure 3

Figure 4

Figure 5