Re: toshiba 32av500u sound but no picture
So then the reading on the transformer 331 70chk would be 223 ohm if the meter was set to 2k ohm.
If the second transformer on the slave board didn't give any continuity from the 3rd pin and side pin could this mean its bad also.
Does a reading of 223ohm on the first make sense?
Thanks for the info, pointers and corrections they are much appreciated.
HotHead
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Last Activity: 06-15-2015, 07:14 PM
Joined: 03-20-2011
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Re: toshiba 32av500u sound but no picture
Ok so here is what I got.
Multi meter set to Ohm/resistance setting 2k.
The fuse on the master inverter (f1 72v 5 amp) reads 0 as though I was touching the leads. The fuse on the slave board reads 0 also but starts to climp up to 1 like I said before.
The 8 Power MOSFETs (4 on each board fdd 8447l)
The 4 on the master board read nothing at all. Multi meter stays on 1. I'm testing the resistance on the 2 leads that are soldered to the board. There is a middle lead but it is not soldered to anything. Either way...Leave a comment:
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Re: toshiba 32av500u sound but no picture
I also notice some scortch marks around the legs of the transformers. Is this normal?Leave a comment:
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Re: toshiba 32av500u sound but no picture
No I do not see any flickering from the backlights at all.
I do have 24 volts coming of the power supply that feeds the 2 inverter boards. Not sure if this is the BL-on.
I did an ohm test on the fuses(white ones next to connector on inverter coming from power supply) The master inverter fuse reads 0 and the secondary starts at 0 and climbs. I stopped when it reached .750 on 2000ohm setting.
The power moasfets are the 8 ic s? 4 on each board...Am I testing voltage on these?
The voltages winding resistance test...Leave a comment:
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toshiba 32av500u sound but no picture
Hello again.
I have tried all inputs on the tv with the same results. Always sound with no picture. I did the flashlight test and do see a picture moving in the background and see the menu screen.
I have encountered this problem before with a different tv and the transformers on the inverter boards were shot.
Seems like the same thing here but before I go removing the two transformers(one on each board) is there a way to test them while still connected or should I test elsewhere before removing them? I also read that some of the 8 medium ic could be bad and should be replaced?... -
Re: Sanyo brightness problem
Ok so I received the ic as15f and swapped it out with the old one.*
I used an exacto and a combination of the two methods mentioned to remove the old piece. First I scored all the legs close to the ic itself and then snapped each one while rocking the exacto back and forth. Went fine until the last leg. Instead of cutting through, the pad came away with the chip. Oops! (note to self, Dont Force)
I ended up following the trace and soldered a wire between both points. Not so easy...those things are darn small!!
I should of snapped a pic...Leave a comment:
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Re: Sanyo brightness problem
You are spot on! 16 through 22...
16. 7.26
7.27
7.24
7.22
6.85
6.83
22. 6.87
Ordered the chip and will wait a long 3weeks. Now like you said the hard part...! Removing the old chip. :-(
Sooo feel like ordering a hot air desoldering station but can't justify the cost. No idea when I'd need it again...but it's tempting. Lol
Gonna look for solutions. I guess I have time.Leave a comment:
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Re: Sanyo brightness problem
Well getting the chip seems to be easy enough. There are numerous sellers. In your opinion would you think there are more faulty parts causing the excessive failure in this ic?
Also if you don't mind me asking another question...why weren't the VGMA 16 through 22 important, I figure they are test points for the same ic?
I guess my big question now is replace the ic(and try my hand at smd soldering) and hope there is nothing else wrong or buy a complete new board(at a higher cost) and hope it functions.
Any advice?Last edited by HotHead; 06-22-2014, 05:51 PM.Leave a comment:
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Re: Sanyo brightness problem
Thanks for the quick replies...
Moreno83, what board were these caps on and where were they located? A visual inspection on my boards show no signs.
Tom66, here are the results from testing the VGMA 1-15.
Starting with 1 and ending with 15
5.82
5.37
5.37
5.37
5.37
5.37
5.37
5.37
5.37
5.37
5.90
6.30
7.31
7.31
7.28
No idea if this is good or bad!?Leave a comment:
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Sanyo brightness problem
Hi
TV model is a sanyo DP42848
It has a brightness problem. You can barely see the image or tv menu. I've tried resetting the colors, brightness, tint ect and still the same problem on any source input.
Seeing i have sound, i can still see the image and the tv does not shut down and after reading some and reading some more would it be logical to suspect the t-con board t420gw01 v2 to be at fault.
More so the ic chip as15-f?
When the tv is on this chip gets real hot! Can't touch it for more than a half second. Is this the chip that controls brightness,color,tint... -
Re: Samsung ln40b550k1f no picture but has sound
Ok, so I am back after a long wait. Here's the update!
Ordered some transformers qgah02095 012tm32c from overseas (instead of qgah02095 ny0924db) and wasn't too sure if they were the same even though they were for the same board.
Tested the resistance of each transformer and they all appeared good. Just finished replacing all three and the tv is now working with a picture and sound for over 45 min.
Hope it last years!
Thx for the help, this site is tops!!!Leave a comment:
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Re: Samsung ln40b550k1f no picture but has sound
Hi again. I take it from the lack of responses I have done wrong. :-(
Sorry.
I have taken the time to remove all three white transformers from the board and have tested them.
Multimeter set to 2k ohm
Transformer #1
Primary .013 secondary #1 1.171 secondary #2 1.174
transformer #2
primary .013 secondary #1 +#2 zero
Transformer #3
primary .013 secondary #1 1.071 secondary #2 zero
Transformer 3 broke while I was removing it. I forced it. My bad.
But transformer 2 came...Leave a comment:
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Re: Samsung ln40b550k1f no picture but has sound
hi again, sorry for the delay. Been busy but got around to testing inverters and finally was able to upload some pics.
After reading several tutorials i decided to test the transformer on-board as a first step.
not sure if i did the test right. I tried to follow the diagrams on a few sights for primary and secondary coils but got a little confused along the way.
I have edited the photos and put in the results i got with the multimeter. I used two settings, 1: @ 200ohm and 2: @20k ohm.
Again, not sure if...Leave a comment:
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Re: Samsung ln40b550k1f no picture but has sound
Goes off as in the ccfl turns off. no light whatsoever when picture is out.Leave a comment:
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Re: Samsung ln40b550k1f no picture but has sound
Here's the power supply/inverter board. this one uploaded.
It's not too clear....Last edited by HotHead; 05-06-2014, 07:08 PM.Leave a comment:
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Re: Samsung ln40b550k1f no picture but has sound
I dont know why but i cant post pics.
I open it up and there seems to be no visible problems that i can see.
no bad caps or scorch/burn marks.
Are the ccfl s easily accessible, i would think not. Can you test a ccfl?
As for pictures, I'll try again but the page times out.Leave a comment:
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Samsung ln40b550k1f no picture but has sound
Hi
I have a samsung that does power on fine, shows a perfect picture and sound. After about 2-3sec the picture goes off but the sound stays on. The picture comes back on after about 5 sec and goes out 2-3 sec later. It does this four times then the picture does not come back on and the sound is still ok.
I have tried different inputs(cable,av,ect) same results.
I haven't opened it yet.
What possibilities could it be? Most post I've read have been the inverter board, t-con, bad bulb but these post all said no picture at all.
Any insight would be a great h... -
Re: Adding a volume control
Thank-you for the replies and here are a few pictures. I hope they are clear enough.
momaka, yes the t.v. will be sending the audio to the sub (2-ch) and then the sub to the speakers. I believe it does amplify.
999999999, i do believe that the amp for the speakers are in the sub, new here so forgive me if i am wrong but the amp is the 7ic s at the bottom. No? The output audio of the t.v. through the jacks are not adjustable from the remote or t.v. menu.
I don't think i'll need independent adjustments as i...Leave a comment:
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Adding a volume control
Hi
I have a Craig cht742 subwoofer (output 30w) and speakers. The volume used to be controlled by the receiver but the receiver is no longer working.
I'd like to use the speakers connected directly to the tv audio out but they play at full volume when powered on.
Is there a simple way to solder a volume control directly to the sub and control all out audio?
Any help or direction would be appreciated. -
Re: Tube tech?
I should of put the make and model.
It's a Victor (1939) A-31 Globe TrotterLeave a comment:
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