Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

[grimacelord]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

1) So are they 0.5, 0.4, Ohms, K Ohms, M Ohms.
2) What resistance scale do you have the meter on: 200 Ohms, 2K Ohms, 20K Ohm, etc.
3) What did you use for GND for the meter?
It is impossible to all 3 power supplies output showing <1 Ohm.

It's an auto-ranging DMM by Klien Tools: https://www.amazon.com/Multimeter-Au.../dp/B018EXZO8M

I used the J622 jumper labeled GND in the same area as the ones you wanted to check. Should I not have used that? There are other GND points in the general area of the board. I'll try it from another.

Could my meter's battery need replacing? When I get back to work, I'll take readings of the same jumpers again just to make absolutely certain that is what my meter reads.

Hell, I'll grab another meter that I have too in case something is weird about this one. I'll report back in a couple of hours.

[grimacelord]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

Alright. Took new readings and had my wife take some pictures. Unfortunately, it's not much different than what I got last time.

I apologize for the blur, but it shows what it was intended to. Black probe on J622 GND, red probe on J620, J621, J623 respectively. These are the readings I get.

[budm]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

At this point I think there is something going on with your meter.
Try taking the resistance reading on one of the 3 diodes (they are sitting in parallel with each other right next to the big yellow transformer.

[budm]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

BTW, do you also have some resistors, especially low Ohm one that you can check with your meter to see what it will show on your meter.
The batteries indicator on the meter, does it show the battery symbol when battery is good or when it is bad? See user manual if you have it.

[grimacelord]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

At this point I think there is something going on with your meter.
Try taking the resistance reading on one of the 3 diodes (they are sitting in parallel with each other right next to the big yellow transformer.

I took a resistance reading of one. When it first put the probes, it started around 2 Ohms and steadily increased. Removing the probes and placing them back on the diode, it resumed from wherever I took the probes off at last, but this time, it decreased. Normal?

BTW, do you also have some resistors, especially low Ohm one that you can check with your meter to see what it will show on your meter.
The batteries indicator on the meter, does it show the battery symbol when battery is good or when it is bad? See user manual if you have it.

Yes. This meter does show a low battery indicator, but it only lights when the battery needs to be replaced. It is not currently lit.

Also, I don't have any spare resistors at the moment.

[grimacelord]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

I pulled out another DMM I have and took readings of the same jumpers. Same readings.

I mentioned in the original post that I bought both main board and power board replacements. The replacement boards are doing the exact same thing that the original boards were.

When I fully connect all cables between all of the boards and plug in the power, I hear that pulsating buzzing sound coming from one of the transformers on the power board. On your advice, I discovered that unplugging the main cable to the main board causes this sound to stop. Both main boards I have are doing this - the original one and the replacement I purchased. What are the chances of that?

The only thing remaining consistent is that main cable between the two boards. Could that be responsible for what I'm seeing here?

[budm]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

OK, if you disconnect the cable between the power supply and the main board then test those 3 jumpers again to see what resistance you will get, you were getting around 13 Ohms before so I cannot see why it went down to <1 Ohm, something is not making sense to me right now.

[grimacelord]

Re: Phillips 55PFL5601/F7 - No Standby, No Power, Fluctuating Voltages...

OK, if you disconnect the cable between the power supply and the main board then test those 3 jumpers again to see what resistance you will get, you were getting around 13 Ohms before so I cannot see why it went down to <1 Ohm, something is not making sense to me right now.

Alright, with the main board disconnected and all other boards and cables still attached, here are the resistance readings of those 3 jumpers:

J621 56.5 K Ohms | (Second reading about 3 minutes later) 56.6 K Ohms
J620 36.9 M Ohms (and rising)| (Second reading about 3 minutes later) 2.24 M Ohms and dropping
J623 3.0 and climbing | (second reading about 3 minutes later) 0.8 and dropping

The second reading on J623 above seemed to resume declining from the initial reading of around 3.0 Ohms I got. J620 was weird, it initially read 36.9 but after holding the probes there long enough, the DMM auto-ranged itself down to around 2.2 omhs and dropping.

Using my other DMM: Here are the readings of the same jumpers with a different DMM:

J621 56.6
J620 30.5 and climbing
J623 3.0 and climbing