Magnovox 32MF231D

[broksonic]

I picked up a Magnovox 32MF231D tv that has problems and am looking for for some help.

First let me say i know nothing on using (or owning) test equipment. I have no problem with doing some solder work however.

When plugged in the power light (green) comes on and stays on for about 10 seconds, then blinks once, stays on for about 10 seconds again, blinks once then repeats one more time then powers off.

I pulled the back to check the caps of all the boards. All looked good. Also didnt see any other problems with the boards that i could see.

When powered on with the back off, i notice when the front power light blinks off, a green light will blink on in the scaler board (main board)(part # 31381586672). At the same time a red light will blink on the backlight inverter master board (part # KLS-EE32C1-M (P) Rev .03.

Any suggestions as to where to start?

thanks

[retiredcaps]

Re: Magnovox 32MF231D

Any suggestions as to where to start?

Post clear focused top down view of all your boards following the instructions in my sig file below exactly. We want pictures in this composition

https://www.badcaps.net/forum/showpo...94&postcount=1

You will need a multimeter to do some basic voltage tests. If you don't have one, borrow one and post a picture of it.

[broksonic]

Re: Magnovox 32MF231D

OK, found my camera stuff (or whats left of it.. had a house fire, lost alot of it).

I did find my multimeter, thought i lost it in the house fire. Wonder what else i could find if i keep looking.

Let me know if you need any others.

Thanks again.

[budm]

Re: Magnovox 32MF231D

You may want to do some visual inspection on both side of the main board aslo:
https://www.badcaps.net/forum/showth...31D#post232681

[selldoor]

Re: Magnovox 32MF231D

Hi - Photos are quite good thanks- please can you do the backs of the boards and name them as you have the fronts.
Also can you do a close up In picture 1 of 7802 Black rectangle with 8 legs bottom right corner near the silver box ( Tuner Box)
Also at the top of the board there is a green item with F73 on it can you do a close up of it. I would also like you to do a resistance test. Set your meter on ohms and touch the
probes together and note the result. Now put a probe on each end of the green item and advise the result. For this you just need the board on it own and not powered.
Good Rule is Measure Voltage Power On.- Measure Resistance Power off.


Further tests will follow. Practice with your meter on batteries and any odd bits of old electrics you have in order to get used to holding the probes and reading the meter. Do you have instructions for it?

[retiredcaps]

Re: Magnovox 32MF231D

First let me say i know nothing on using (or owning) test equipment.

Hmm, I think I have seen this multimeter model before in another thread. If you have never used a multimeter before, take a look at this short 5 minute tutorial by my fellow Canadian.

http://www.youtube.com/watch?v=bF3OyQ3HwfU

[broksonic]

Re: Magnovox 32MF231D

Ok, as per request...

Back of boards, chip 7B02, and F73 chip.

I checked the back of the boards but didnt see anything.

I tried to check the resistance on F73 chip.. DMM started at -1 and continued dropping. It never leveled off and i pulled the probes at -1.80.

I included a picture of what i had my DMM set at (which could be wrong as i have never tried to test resistance)

[retiredcaps]

Re: Magnovox 32MF231D

I tried to check the resistance on F73 chip.. DMM started at -1 and continued dropping. It never leveled off and i pulled the probes at -1.80.

1) F73 looks like a fuse. Traditionally, most pcb boards are labeled with designators. For example, "F" stands for fuse. However, Magnovox decided to number their components. So 3019 is the board designator for fuse F73.

2) If you had a fire, your multimeter may have been damaged by fire and smoke?

3) Put your multimeter on 200 (two hundred) ohms.

4) Touch your red and black probe together. What is your reading?

5) Now place the red probe on one side of F73 and black on the other side. What is your reading?

6) The "1" on the left hand side of the screen means "out of range".

[retiredcaps]

Re: Magnovox 32MF231D

There are 3 voltage regulators on the back of the main board. I circled them in red.

The following will require the TV to be plugged in with power on. DO NOT touch anything on the power board or any of the heatsinks.

1) Put your multimeter to 20V DC (press AC/DC button until it shows DC).
2) Put your black probe on a main board ground screw. Leave it there for all measurements.
3) Put your red probe on each pin (ignore the top fat tab). Measure the "cut" or middle pin as well.
4) For each regulator you should have 3 readings. Report them like this.

Regulator 7710
part number 1084-33
pin 1 = 0.00
pin 2 = 3.3
pin 3 = 5.0

5) Note if the readings are steady or fluctuating.

Note: I don't know if this board will be "upside down" or not when you take the voltage measurements. If it is, use cardboard for separation so it doesn't touch any other board.

[broksonic]

Re: Magnovox 32MF231D

WELLL i didnt think it was damaged but now im not so sure.
@220 ohms and touched together started at +180.0 and ran down into neg #s.

Tried to do a voltage test on a NEW dc battery.. showed 000

Turned it to continuity and it just beeped without touching anything.

Would say its out, so will have to get a new one.

Any suggestions for a new one?

[retiredcaps]

Re: Magnovox 32MF231D

Any suggestions for a new one?

1) Try taking a q-tip with isopropyl alcohol and cleaning the input jacks. Let it completely dry. Afterwards, try touching your probes together again. If it is working, it should read less than 1.0 ohms. If not, do NOT use this multimeter on any voltages as it is damaged.

2) What is your budget for a multimeter?

3) Are you in a hurry to get one?

[tom66]

Re: Magnovox 32MF231D

It could also just be a low battery, maybe?

[broksonic]

Re: Magnovox 32MF231D

Still no good on the meter...

hmm budget for new one... lets see, rent due, power due, phone/internet due, water due...all today.... you get the idea i bet...

sooner the better..but with all the "dues" i could wait a bit.

[tom66]

Re: Magnovox 32MF231D

Still no good on the meter...

hmm budget for new one... lets see, rent due, power due, phone/internet due, water due...all today.... you get the idea i bet...

sooner the better..but with all the "dues" i could wait a bit.

You can get a real cheap one for about $3 from some big hardware store in US. It's not as fancy as your other one, but it will do the job fine for the task at hand.

[retiredcaps]

Re: Magnovox 32MF231D

You can get a real cheap one for about $3 from some big hardware store in US.

Tom66 is referring to this one ...

http://www.harborfreight.com/7-funct...ter-98025.html

[broksonic]

Re: Magnovox 32MF231D

Ok, New DMM purchased (see pic).

With the new DMM set at 200 ohm the F75 (fuse) showed a .07

The 3 voltage regulators (refer to picture) are as follows..
DMM set at 20V DC

7T10 pin 3 (top one in picture) 12.03
pin 2 - 5.01
pin 1 - 0.00

7B45 pin 1 (right side in picture) 5.15
pin 2 - 3.30
pin 3 - 0.00

7U28 pin 1 (bottom one in picture) 4.12
pin 2 - 3.26
pin 3 - 2.60

Only flux i seen was when the lights flashed (refer to 1st post in thread)

Wasnt sure about the part numbers. If they are stamped on the top of the regulators i couldnt really read them (@49yrs old my eyes are not the greatest anymore) have to get a stronger magnifying glass.

Also noticed a change in the lights flashing. (refer to 1st post again)

Now when plugged in front power light comes on as well as the scaler board green light, the master backlight inverter boards red light flashes once.

Both green lights stay on for about 25 seconds then flash off and the red backlight flashes 2 long flashes.

Green lights come back on for about another 35 seconds and flash off while red backlight flashes1 long 2 short.

Green lights come back on for about another 30 seconds and system powers off.

Power switch on front will now turn set back on (wouldnt before), and the flashing will repeat.

[selldoor]

Re: Magnovox 32MF231D

Set your meter on 200 ohms and touch the probes together - what do you get?

"Wasnt sure about the part numbers. If they are stamped on the top of the regulators i couldnt really read them (@49yrs old my eyes are
not the greatest anymore) have to get a stronger magnifying glass."

Can you take "macro" photos of them and post, sometimes easier to see that way.

[selldoor]

Re: Magnovox 32MF231D

Two things to check on the board in pics 1 and 4.
On the underside left hand side bottom there is a 5001 looks like a cold solder on pin?
Also the area is stained - can you look at closely and see if you can see why?
On the other side - pic 4 top right ah-ha its actually near 5001 inductor again! there is a small white box what does it say on it . I think it may be another fuse could be that F88 sticker is telling us something. Please test as with other fuse.
Please also look at the soldering on cap 2002 - probably just shadow but looks odd.

[broksonic]

Re: Magnovox 32MF231D

Set your meter on 200 ohms and touch the probes together - what do you get?

0.03

Can you take "macro" photos of them and post, sometimes easier to see that way.

Not sure which # on the chip is the part #, but here is what is on the chips

7U28
PHD38N02
LT
PEm0610 A1

7B45
L1117
33
GK1S0613

7T10
L1117
50
GK1LJ610

[broksonic]

Re: Magnovox 32MF231D

Two things to check on the board in pics 1 and 4.
On the underside left hand side bottom there is a 5001 looks like a cold solder on pin?

Looked ok, but retouched it. No change.

Also the area is stained - can you look at closely and see if you can see why?

Have no idea on the stained areas. There are stains in multiple locations... maybe heat related? Used a bit of rubbing alcohol on a q-tip and it came back light brown but didnt come up easy and i didnt rub long.

On the other side - pic 4 top right ah-ha its actually near 5001 inductor again! there is a small white box what does it say on it . I think it may be another fuse could be that F88 sticker is telling us something. Please test as with other fuse.

Showed a 0.08

Please also look at the soldering on cap 2002 - probably just shadow but looks odd.

Looked fine