Pioneer Kuro KRP-500PW dead, 8 blinking blue LED

[davorin]

Hello

I know there are resources on the web explaining exactly this behavior...but it is not the voltage regulator as I already replaced it...
Furthermore...the PCBs look totally different than on the resources found on the web...

The orange LED blinks once every 3 to 4 seconds as well when pressing the Info button on the remote...

Attached a picture of a PCB (dunno what it is doing). When switching on two LEDs on top and bottom of the PCB are turning green, then when the TV goes off again, just the top LED turns red.


Someone has a service manual of the display?

[eKretz]

I've got a PRO 111FD, and I remember doing some reading about this issue. As I recall the are more than one possible cause for this, and the amount of red blinks helps pinpoint it a little better. Try a search at AVSForum and I bet you'll get some better info.

[Armadillo]

8 Blinking blue indicates there is a Failure in IIC communication with the panel main microcomputer. Check the communication cabling whether there are firmly connected.?

Check 3.3v is produced by regulator IC8331.

[Ronnyw]

I have the same problem with my KRP-500P panel, blue LED flashes 8 times and then pauses before flashing 8 times again. It would occasionally switch on, last time left it for a week and was able to switch it on, but no more. Media receiver seems fine i.e. no flashing LEDs.

Having checked the service manual the attached picture shows what I believe are all the components/connection it could be.

In my case I have checked the two regulators, and have measured the volts as below:

IC7001 (MAIN board)
Pin2 has 5v panel switched off or on
Pin4 has 3.3v when start the set and then drops to 0

IC8331 (AUDIO board)
Pin2 has 0v (both when panel is off and when start the set)
Pin4 has 0.05v (when panel is on)

I do not have the knowledge to know which one (or both) are faulty or if the cause is something else?

[Armadillo]

IC8331 Pin 2 is supposed to be getting 6.5V from the Power Supply Board.
Check the Power Supply Board for the output voltage.

[Ronnyw]

Seems the Power Supply Board is not supply power to the Audio Board.

I checked some of the test points on the Power Supply Board and they are showing as 0v

TP23 (should be 12v), showing as 0v
TP24 (should be 6.5v), showing as 0v

The only test point that is working is TP25 which correctly shows 5.1v. Other cable connections I checked that that show what voltage they should have on the board also show 0v.

The board is getting power at its source as that shows around 177 ACv

[Ronnyw]

Managed to switch the TV on today a few times and power was all good, and then again it would no longer switch on, going back to the 8 Blue LED’s, and no distinct click sound (Relay switch?) that you would normally get when the set is switched on. However I also noticed today that a few times, after removing power supply to panel and re-connecting that  it would have two rectangles red and blue moving right and left with blinking alternating red and blue LEDs. Once or twice it ended up in standby by mode with just red LED, but failed to switch on, or it would try, could hear the distinct “Click”, and blue LED but then the media receiver was in Standby mode (Red LED), and panel shutdown again a few seconds later.

As I do not know where the problem is or which board to replace (Power, Audio or Main), it looks like I either need to take it to an authorised repair workshop, which could be costly so may start to look for a new TV, as parts are also now getting harder to get hold off for these sets.

[Armadillo]

This used Pioneer AXY1203 board is surprising not cheap at £125.00, you believe that shit!.
I suggest you get someone nearby you to repair the board for you at a token then.
I heard there is a job forum somewhere.

[Armadillo]

The start up circuit is quite typical. A bleeder current, half wave rectified is drawn from the AC Line to kick start the power supply IC101 and drive the relay into contact. So you should be looking around IC101 area.
Picture the IC region front and back so that we may look trace for you.   

[Ronnyw]

Thank you for your input.

Attached picture of front of board for IC101

[Ronnyw]

Attached picture of back of board for IC101

[Armadillo]

I imagine IC101 could be a TOP224YN. That area is congested, no easy probe.

Below is just my suggestion for your consideration. I could be wrong, it is dangerous, If you are not comfortable, please don't do it. I welcome others to make correction and improvement.

I would dismantle the power supply module and placed on a insulated table with wide working space.
Based on the block diagram.

The first thing that happen when you plug power in using "isolated transformer", is to confirm connector P6 for STB5.1 volts and connector P7 for STB3.4 volts. Without the Relay RY002 being energised, no other power supply is energized.

To simulate successful handshaking and checking from other boards, I would jumper RY002 to energize the remaining power supply so that I can measure all the voltages at the connectors.

Thus with above, I can either confirm that the power supply is working or identify the parts that failed to work.

Alot of work, I would say. Maybe buy a new TV would be safer and easier. 

Above just my 5cents.