My service tech said my d-board can't be replaced/repaired

Appears to be an issue with the power supply - that is why unit shuts down to protect itself.

http://www.givemefile.net/smanuals/project_tvs/sony/kdp-51ws550.html
http://www.fixdevice.com/smanuals/file/8939.html


https://www.completeservicemanuals.com/Sony/CRT-Projection-Television/KDP-51WS550-Service-Manual/prod_141.html


Service manual download links above, two free one pay for....

Hi,
I hope our experts have been provided you helpful info in chat session about tv problem yet you can let me know if further help is needed as being Sony tv tech I can help you more.
Thanks.

you will need a ohm meter.....check IC406, audio amp,PS401, PS402,flyback T8005 high voltage on D board,.....you can get parts at Mats Electronics # 1-800-628-1118

hello AKB circuit (automatic kine bias), the timer/standby indicator blinks for about 30 seconds then goes to the self-diagnosis function. Something is wrong with the video. Check video out, Q705, 732, 761 and other components on the C board, also check Q218, 219, 220 on the A board. In addition, unit could be in IK blanking, try turning up screen slightly

regards
shaun

Type in space bar Understanding sony Blinking codes this will take you to a website telling you what each code means.

HI. i have found a DS Mount(Board), that matches the model number given. it is available for purchase online and can be delivered to your address as well via ups/fed x. I will post the link to the site where you can order asap.

CLICK HERE TO BE DIRECTED TO THE PARTS STORE FOR YOUR REPLACMENT BOARD(DS MOUNT).

Hi,
Below is an exploded view shows all boards location in KDF-51WS550
Hope this will help you to identify required D board.

I have a power supply board(g) a audio board and video board and all other boards that im looking to sell they are all good might sell cheap cal me at 573-433-1925

6 times, Diagnosis: LOW B OCP/OVP (Overcurrent/over voltage). Possible causes: +5 line is overloaded. (A, B boards), +5 line is shorted. (A, B boards). Symptoms of the problem: No picture.
http://www.somelifeblog.com/2007/08/sony-tv-led-blinking-codes-what-does-it.html

also found this

CHASSIS: AX1/AX1X/RA6/RA6A
MODEL: KDP51WS550, KDP57WS550, KDP65WS550, KP46WT500, KP46WT510, KP46WT520, KP51WS500, KP51WS510, KP57WS500, KP57WS510, KP57WS520, KP65WS500, KP65WS510
SUBJECT: Picture gets bright then shuts down. After repairs tech noticed a mark was created on all 3 CRT's.
CAUSE: Found Video Output was defective causing the failure of the 200v line. 200 volt line has two fuse resistors R7301 (10 ohm 1/4w) on the CB Board. R8225 (1 ohm 1/2w) on the D board. R8208 (0.47 ohm 1/2w) also on the D Board. All three resistors are in series. One or all 3 could be open. After replacing 2 resistors and Video Output IC set returned to normal operation. CRTs will need to be changed due to phosphor damage. On Models KDP-51WS550, KDP-57WS550, KDP-65WS550 CB Board resistor is R9335 10 ohm 1/4w. D Board resistor is R6509. NOTE: This resistor may be a jump wire according to the schematic. Models: KP-51WS520, KP-57WS520 These models have a fuse resistor on all 3 CRT Boards. CB R9335 10 ohm 1/4w CR R9110 10 ohm 1/4w CG R9211 10 ohm 1/4w On the D Board R6509 is a jumper wire according to the schematic.