Planar PL2010M-BK -Black screen

[K_K3N]

Re: Planar PL2010M-BK -Black screen

I did replace 3 bad caps .. could they have blown the fuses?

[budm]

Re: Planar PL2010M-BK -Black screen

Unless you created the solder bridge when you install the two new caps which are connected after the fuses. Those 3 caps you have circle are for the buck regulator circuit to power the main logic/scaler board.
OK AP4501, see spec sheet.
Check the RESISTANCE between S and D pins of all 4 devices.

[K_K3N]

Re: Planar PL2010M-BK -Black screen

ok there are S 1 and D 1's as well as S 2 and D 2's on the diagram

one one side S1 and D1's pass ohms
the S2 and D2's don't

on the other side the chips are flipped , and I get the opposite
S2 and D2's pass ohms s1 and D1's do not

Are the bad or is that normal ?

[selldoor]

Re: Planar PL2010M-BK -Black screen

"Pass Ohms" is not really accurate enough

We need to know that actual results of the test - do it like this
Mosfets

If you have a manual range multimeter, set it to 200 ohms (two hundred). This is for 3 pin ICs only. You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any reading is less than 30 ohms you might have shorted mosfet. Remove from circuit and repeat the tests to verify.

Some mosfets are more than 3 pins. To test those, identify the part number and search for its datasheet. Once you find the datasheet, the pins will be designated source (S), gate (G), and drain (D). It will probably be documented as S1, S2, G1, G2, D1, D2.

Simply test

a) black on pin S1- red on pin G1 - record ohms
b) black on pin S1- red on pin D1 - record ohms
c) black on pin G1- red on pin D1 - record ohms

Repeat for the "2" pins. That is S2-G2, S2-D2, G2-D2.

and post the results - some may be "OL" "OF" or "1"

These fuses blowing seems a common fault so hopefully the mosfets will be good

Check that the caps you replaced are the correct way round (polarity)

I also asked you to post the pictures on this forum - not offsite
so I have re attached them here so they available in future.

[K_K3N]

Re: Planar PL2010M-BK -Black screen

I work night shift .. I'll will run this test tonight after I get home from work
Much thanks

[K_K3N]

Re: Planar PL2010M-BK -Black screen

I have a very old fashioned meter
with dial set to RX 10 ohms
I get the needle to move to about 50 ohms
between the S1 an the G1 on each chip
I get about 35 ohms between S1 and either D1

the other have of each chip I get nothing well the needle barely moves ( stays on the High end of the scale near 200 )

I have some slow blow 2 amp fuses a bit big ( older electronics tend to be )
I am sure I can figure a way to get them on . If that is what is needed.

Again Thanks a Heap,
K_K3N

[budm]

Re: Planar PL2010M-BK -Black screen

"I get about 35 ohms between S1 and either D1" No need to get the new fuses util you remove the MOSFET and test it again off board.
You should get a digital meter.

[K_K3N]

Re: Planar PL2010M-BK -Black screen

I went a head and put on a pair of fuses .. I get a flash on the screen when 1st powered up now . so the tubes work . I take a better look at video board now.

[budm]

Re: Planar PL2010M-BK -Black screen

So the backlights stay on? or they flash on for seconds and then go off.

[K_K3N]

Re: Planar PL2010M-BK -Black screen

they flash .. then go out .

[budm]

Re: Planar PL2010M-BK -Black screen

It should stay on if you have it hooked up to running PC, otherwise you still have problem in this inverter board. Bad lamp, bad MOSFET, transformers, caps will give you 2-seconds to black. All it take is one bad lamp to cause it to go black after seconds.
Also check the fuse to see if they are still OK.

[K_K3N]

Re: Planar PL2010M-BK -Black screen

OK Thank you .. I may close it up for a while ... as I have some other projects waiting to be finished ( computer builds )
Thank you again

the flash is at both top and bottom . with only one fuse it was bottom only ...with a PC hooked up the power light stays green , so it is getting a signal from the PC .

wondering if I still have the eye sight to try an de-solder the mofset's an re-solder new ones on.