MAXENT MX26X3 L2614XW02L no standby light, no power on

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

Typical*1117-18 = 1.8V Fixed regulator, 1117-33 = 3.3V Fixed regulator. Adjustable will have resistor network on pin 1 and pin 2 and circuit ground, the voltage between pin 1 and pin2 of Adjustable should always show 1.25V if it is good.

Read more here: https://www.badcaps.net/forum/showth...999#post300999

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

ok thanks for the tips. ill check it out more and post my findings soon

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

of all these voltage regulators only
the 2 LD1117's have 1.24v between pin1 and pin2
the 84-33 0502AL has 1.3v between 1 and 2
the 84-33 0515CL has 1.28v between 1 and 2
the rest have voltages nowhere near 1.25

is 1.3v close enough to 1.25 to call that an adjustable regulator and declare it good, or is it some other fixed regulator?

are there only the two types? fixed and adjustable?
adjustable is easier to test because its behavior relative to 1.25v can be tested

but to test if a fixed regulator is good, is the only way thru knowing its datasheet?

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

and i just cant find datasheets for these chips!
"1084-33 0515cl datasheet" in google produces ZERO hits.

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

The 1.25V ref for the Adjustable regulator is pretty tight around 2% tolerance.
Can you take the reading of all 3 pins of all the regulators
and report the reading as shown in the format in the link so I can verify all the readings for sure?
Looking at it wit big tab up, the left pin is 1, tab is 2 right pin is 3.
Close up pictures of these 2 also so I can see how they are connected.
the 84-33 0502AL has 1.3v between 1 and 2
the 84-33 0515CL has 1.28v between 1 and 2

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

ok so i may have found the datasheet for this chip by typing in only "1084-33"
looking at
it seems to say this is a 3.3v fixed regulator?

testing each of the pins though, i have 0, 1.29, 2.2

weird when i made the measurements earlier in the picture i wrote it down as 0, 1.31, 2.13

either way those numbers dont line up with 3.3v .... so is this my problem, or am i reading the wrong datasheet? how can i ever be sure?

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

OK, I went back and look at the Voltage readings you had posted:
IC701 (ADJ) 3.33V out, OK. Vin 5V.
IC702 (ADJ) 2.5V out, OK. Vin 5V
ICV8 (Fixed 9V) bad, due to low input voltage on pin 1, it should have 12VDC on pin1. Vin only 4.66V, too low.
IC704 (ADJ) bad due to low input voltage. Vin is only 2.13V, too low.
IC706 (Fixed 3.3V) bad due to low input voltage. Vin is 2.13V, too low.
IC708 (Fixed 1.8V) bad due to low input voltage. Vin is only 1.31V, too low.
IC710 (Fixed 1.8V) bad due to low input voltage. Vin is only 1.31V, too low.
IC712 (ADJ) bad due to low input voltage. Vin is only 1.31V, too low.
IC713 (Fixed 3.3V) bad due to low input voltage. Vin is only 2.13V, too low.

As you can see, 3 of the regulators are fed by the same voltage source of only 1.31V, other 3 are also fed by the same voltage source of only 2.13V.
Typical drop out voltage is about 1.4~1.5V (some can be a little lower, need to look at the spec), it means that for the regulator to regulate the output voltage, the input voltage must be at least 1.4V higher than the desired output.
For example, for the 1.8V fixed output regulator, the input feeding the input pin must be at least = 1.4V +1.8V = 3.2V

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

OK, I look at my spare board and now I remember I try to fix this exact model before, it is commonly known problem with the main board due to poor solder on the BGA for the video processor, you can press on the heatsink then the picture will clear up. If you Google for this model, you will see.
Anyway, I kept the power supply board, if you look at the bottom side, it will have the voltage labels for the connectors.
CN504:
PIN1, 2 = +5VS (5VSTBY)
PIN 3, 3 = Ground
PIN 5 = ENABLE (PS_ON)

CN505: This one is not used on my board.
PIN 1, 2, 3 = +5V swithced (turns on when PS_ON is applied)
PIN 4, 5, 6 = Ground

CN503:
PIN 1, 2, 3 = +12V swithced (turns on when PS_ON is applied)
PIN 4, 5, 6 = Ground

CN501:
PIN 1, 2, 3, 4 = +24V swithced (turns on when PS_ON is applied)
PIN 5, 6, 7, 8 = Ground

CN506:
PIN 1, 2 = +12V swithced (turns on when PS_ON is applied)
PIN 3, 4 = Ground

CN507:
PIN 1 = +5V swithced (turns on when PS_ON is applied)
PIN 2 = Ground
PIN 3 = +12V swithced (turns on when PS_ON is applied)

CN502:
PIN 1, 2 = +5V swithced (turns on when PS_ON is applied)
PIN 2, 3, 4 = Ground
PIN 6, 7 = +5V swithced (turns on when PS_ON is applied)

So check the ENABLE PIN to see if it toggle when power switch is toggled.

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

thanks for all that info...i dont see how pressing on the vga heatsink could help since the standby power light doesnt even come on but i went ahead and tried that anyway with no effect...

in cn504 there are only 3 pins that have wires coming from them
pin 1, 3, and 5
they are 0, 0, and 5.06

none of these pins change voltage when power button is pressed.

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

i think i had my pins reveresed but u get the idea...pin 1 has 5v, pin 3 is ground, and pin 5 should change when power button is pressed... what volts should it have? it just says PS_ON

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

Pressing on that heatsink has to do with pictures problem, not what we dealing with right now. You may find that out after we fix what is wrong and get the TV to turn on to see the pictures.

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

CN504 pin 5 (ENABLE), it should toggle between <1 (OFF) and >2VDC (ON).

[budm]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

It is 11, so I am going to bed, will try again tomorrow, night.

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

i havent taken the power supply board off, but on the front side i can see a little white arrow pointing towards a pin...does the white arrow point to pin1?

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

oh ok well thanks and ill keep trying...hopefully figure this out tomorrow then

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

i did notice that when i measure the voltage on CN6 Pin1 it drops from 4.98 to 3.6 when i push down the power button. when i release the power button it goes back to 4.98

none of the other pins on CN6 do this.
CN6 is where the button board connects to the mainboard. so i imagine it gets a signal via that voltage drop and then is supposed to tell CN401 to send the PS_ON signal to CN504 on the power supply.... but neither CN401 or CN504 do any changing of volts on any pins when the power button is depressed....

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

i see some...corrosion? idk even what to call it but the solder looks cloudy on the VGA connectors... what is that and should i try to clean it up?

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

is there some way i can "trick" the power supply into turning on?

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

like if i jump one of the 2.13v lines to the PS_ON pin?

[triplefour]

Re: MAXENT MX26X3 L2614XW02L no standby light, no power on

im not gonna try anything sketchy tonight ill wait till tomorrow to get some professional opinions