Panasonic Fridge (Refrigerator) Freezer NR-B30FX1 not cooling inverter compressor not working

[msanman]

Can anyone shed some expert light on my problem of a Panasonic Refrigerator Freezer please ? Its Model NR-B30FX1 (Same as a NR-B30FW1/FG1) an Inverter. I have started to pull what little hair I have left on my head trying to fix it and its probably something easy and I can afford to purchase a part to fit it myself :-) The description is a bit long but want to provide as much info as possible.

The unit is just over 5 years old and has worked perfectly but was working harder, little more noise from the compressor/unit and then one morning the low temp alarm was sounding and no cooling was occurring. The power is on, all lights on the  Refrigerator  working when doors opened, front Control/Temp set Display is working but showing lowest default temp for Freezer/ Refrigerator /Vegetable compartments. There is no frost or icing in the freezer (FC) compartment, and the three phase DC inverter compressor and VC Freezer Fan is not running in normal mode. I have stood up the Refrigerator for a few days and let it dry out, but to no avail no difference powering it back on.

This  Refrigerator has a front display panel for temp setting and fast freezer etc, which attaches to Man PCB with the micro computer, and has a separate Inverter board which supplies power to the compressor and the Main PCB.

In a nutshell I need some advice on how to fault the inverter board and compressor, and how to detect a IPM start signal is being sent to the inverter board from the Main PCB, the proving of the output voltage/frequency/ and finally prove compressor not faulty/locked up please ? I have watched a good video on here for faulting an inverter  Refrigerator but it had a dedicated inverter board with J15 two wire control link, where mine has a major inverter board. but it did allow me to prove the windings were okay on the inverter and to understand an inverter Refrigerator .

 

Main PCB

I have checked all voltages, and relays are okay for VCC heater and Defrost heater. Don't know ho to tell its telling the inverter board to switch on though.

I am handy with a multimeter and basic electronics, so have downloaded the service manual and tried the Test Control checks;- Compulsion FC start - s/c Test Terminal 1 & 3, starts both Refrigerator (PC) Fan and Freezer (FC) Fans. the s/c Test 0 (Zero) Point and Gnd does not start the Compressor but the 'C' indication comes on the front panel. There are other Test points on both PCB but do not have any info for what they do, and the self diagnostic function on the front display module is just blank (dash/dash).

Compressor

I have measured the compressor windings on Con703, and all appear good at 6.9 Ohms, and meggered them to Eth and no issues. The protector is fine. I have on my multimeter with a KHz frequency setting but only see a brief flash of KHz on each terminal of three W,U &V), and flash of voltage, not enough to prove consistency.

Sensors/Thermisters

Checked resistance of all sensors for resistance out of cct and in cct, the voltages look good. I can't find the  ATC Sensor on the wiring and schematic diagram, which is used to determine difference between other sensors and ambient temp I think, so this could be faulty but unable to test it?

Inverter Board/

I have checked all voltages, and the Bridge rectifier working, but the Intelligent Power Module (IPM700) SLA6805M, is cold or the heat sink is anyway. So don't know to test the control signal into it to prove its being told to switch on and prove the output voltages ?? Help Please ??

Power on Start up Sequence

Both Fans operate on power up, 3 way valve makes a noise, damper step motor does a cycle, but no noise on the compressor, and a blip of voltage/frequency on the outputs from inverter board to Compressor (terms W, V and U)

 

I can't find a full component cct diagram of the PCB boards or much on proving the inverter complicated cct. There is a data sheet on the IPM but looks complex. But now basically stuck.

[DurhamAppliance]

not familiar with this model but have you tried diagnostic mode.. check for errors.. 

[DurhamAppliance]

this is the procedure to advance into diagnostics self test 

[msanman]

Hi, thanks for your advice. I have ran the diagnostic and get the "-" displayed on Fridge and "- -" displayed on the Freezer, tried the history and get "H" and "- -" so no history as per Service manual section 9. Would the Section 8.3 Test 0 point and Gnd short on Main PCB start the Compressor ? as it doesn't on mine ?

I read Appliantology's " How to Troubleshoot the New Inverter Compressor Refrigerators - very good. Windings are al the same at Have not checked current draw from power supply to Inverter IPM chip as all soldered in cct. As the Inverter OCB converts the power and send it to main PCB CMOS 15-5Volts, and all voltage check points look okay on Inverter board.

I obtained the IPM  Data Sheet SLA680MP here, and wondered if I can test any Control Voltages in, not sure but is it Vin (Hin1,2,&3 Pins 9, 8 & 7) and (Lin 1, 2 and 3 Pins 20, 19 &18) but may be square PCM wave ? I can check for VCC 15V on pins 5 and 23 to Gnd and input High Voltage 300-450V on Pins 11,10 and Gnd I think to prove Voltage getting to Chip. But its the control signal form the mother board I am keen on understanding. What do you advise ?

http://www.allegromicro.com/~/media/Files/Sanken/Datasheets/SLA6805MP-Datasheet.ashx

 

[Samurai Appliance Repair Man]

1 hour ago, DurhamAppliance said:

this is the procedure to advance into diagnostics self test 

Hey, Brother Durham, if you have that service manual, would you mind uploading that to the Downloads section so it's available for others later on?

[DurhamAppliance]

14 minutes ago, Samurai Appliance Repair Man said:

Hey, Brother Durham, if you have that service manual, would you mind uploading that to the Downloads section so it's available for others later on?

lol, i left you a message regarding that this morning

[msanman]

Checked all voltages on boards, and swapped out Main Control Board, checked thermisters/sensors and okay but can't find the sensor -ATC, for ambient room temperature to check it ?

Thinking it's the compressor ? So checked the three windings and all good 6.9 Ohms and no connection to Eth.  Managed to get spare correct spec Panasonic compressor but not fitted, just connected the U,V&W three pin lead on to it and eth and no pipes connected. When power up refrigerator the Compressor does actually run for 2 seconds then stops, would of thought it would of ran for some time. Is this normal that it will stop after a few seconds and shut down as its not connected to the pipes. Does this prove the old compressor is faulty or it's something else ? Any  advice please ?