Re: LG 55LW9500 no video, no audio
Thanks for the help Nick.
The heat soak on the heatsink of IC101 provided no change.
I used a heat gun 100C (212F).
I checked the SMD caps around the HDMI chip and found no anomalies, however, I did find caps under IC101 were all reading 17 to 18 ohms.
These are all connected to the +0.9v core which feeds into multiple VDDC's AON_VDDC and AON_POR_VDD on the as well as TVM_OSC_AVDD on IC101/BCM35230.
Has anyone experienced this fault?...
krustyone
Member
Last Activity: 09-03-2023, 04:40 AM
Joined: 11-04-2013
Location: Melbourne
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Last edited by krustyone; 04-21-2020, 06:08 AM. -
Re: LG 55LW9500 no video, no audio
I checked the gate and source pins and they are both at +12v.
After disconnecting the LVDS cable, the +0.96v is no longer present.
The next step is to trace back the PANEL_CTL signal to IC602 which appears to control the main on/off functionality and miscellaneous related tasks.
Suspect the chip is working with some level of normality as the IR function is working however, I'm not sure what the purpose of the MICOM MODEL OPTION to the bottom left of the image....Leave a comment:
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Re: LG 55LW9500 no video, no audio
Thanks for your help budm.
I couldn't find the SMD fuse you spoke of however, I traced back what should be the 12v rail at the TCON, which is reading +0.96v back to the mainboard.
The source of Q507 in the PANEL_POWER section is reading 12v as it should coming from L511, PANEL_CTL is reading high at 3.5v however the drain of Q507 is reading +0.96v, the same as the TCON.
I suspect Q507 has failed.
Apparently it is common to replace Q505, Q506 and Q507.
Can someone please confirm...Leave a comment:
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Re: LG 55LW9500 no video, no audio
Ok. All voltages to and on the mainboard checkout ok and are within tolerances.
All on board power rails are correct.
All voltages on the TCON board appear to be missing.
PDIM is at 3.2v
INV_ON = .038
The heatsink above the XD Engine is warm to the touch.
TCON processor is cold.
There are 2 flashing leds on the LED driver boards that are flashing in sync.
Anywhere else you would like me to check?Leave a comment:
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Re: LG 55LW9500 no video, no audio
Here you go.
Checking voltages now....Leave a comment:
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LG 55LW9500 no video, no audio
Hi all,
I have an LG 55LW9500 that powers on by remote and the sensor touch and yet displays no image or back light.
There is no image with a torch.
24v is available to both LED driver boards and all supply rails check out ok going to the mainboard.
I tried hot air reflow of the CPU on the mainboard with no change.
Before I spend money on a new mainboard, does anyone have repair pointers for an EBT61548601 mainboard.
Thank you. -
Re: LG 50LA6230 Service Manual
Thanks Diif.
It actually doesn't look that bad but I can count 4 to 5 LEDs that are out.
The LEDs are obviously in series?Leave a comment:
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Re: LG 50LA6230 Service Manual
Hi Neil,
Correct. It has a flicker to the left of a screen.
Just wanted to arm myself with the manual first.Last edited by krustyone; 04-17-2020, 05:36 AM.Leave a comment:
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LG 50LA6230 Service Manual
Hi all,
Just wondering if anyone might have a service manual for a LG 50LA6230-TB or similar please.
Chassis is AAUYLJD.
Thank you. -
Re: Yamaha RX-A1030 I Protect
Ok, an update.
The board with the +LB, -LB supplies is impossible to get to with the amp fully assembled.
I can confirm AMP_LMT is producing 3.1v at the digital board.
I can also confirm that -LB is missing in that it is only reading +1.5 however +LB is at +54.6 which based on another schematic I have for the RX-v1067 with the same Main 1, 2 and 3 boards, is normal.
Currently, all speaker outputs are showing +1.2v.
I couldn't find any issues with Main 1 or 2 after checking all voltages and transistors etc...Last edited by krustyone; 03-10-2019, 07:59 PM.Leave a comment:
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Re: Yamaha RX-A1030 I Protect
Thanks R_J.
I’ll do those checks and report back.Leave a comment:
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Re: Yamaha RX-A1030 I Protect
Can someone please help me to understand the +LB & -LB supply on page 152 in B5. Both of these voltages are missing.
I found a schematic that utilises the same amp and supply boards as the RX-A1030 that shows test voltages.
After pulling the receiver apart to get to the MAIN board, I disconnected the MAIN 1 & 2 to concentrate on the +LB & -LB supplies that are generated around Q1009 & Q1010 from -B & +B.
I have connected MAIN directly to the transformer which is connected directly to mains....Leave a comment:
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Re: Yamaha RX-A1030 I Protect
After conducting the checks you suggested and having erratic voltages depending on what relay had kicked in, I decided to cut the power to both each of the amps progressively.
It appears MAIN 1 might be the cause to pull the -B rail down as I still had rails that were different by 10v.
After both amp modules were disconnected, both the -B & +B rails held steady at 55v respective of their relevant polarities.
What I did note was that -LB_R, +LB_R, -LB_L and +LB-L were all missing the -59v as listed at CB106.
...Last edited by krustyone; 03-05-2019, 05:23 AM.Leave a comment:
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Re: Yamaha RX-A1030 I Protect
Correct. Although they are both linked at intersection B2 on page 152 so what ever the voltage is on one, it will be the same on the other.Leave a comment:
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Re: Yamaha RX-A1030 I Protect
Also, I_PRT_L & R are reading 59v.Leave a comment:
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Re: Yamaha RX-A1030 I Protect
Thanks for that R_J.
I check both 12v supplies and they appear to be okay.
Doing some more checks around MAIN 1 and MAIN 2, I noted the positive and negative rails to output stages where around 55 volts in stead of 59.
Also - and + LB_L ate showing around 2 to 4 volts. Well short of the expected 59 volts.
I should also add that when the second relay kicks in after about 3 seconds, the 55 volts at the output stages progressively begins to fall although this has only happened once or twice when it...Leave a comment:
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Yamaha RX-A1030 I Protect
Hi all,
Normally fix TV's however this is the first amp I have worked on in the modern era....
The amp after resetting the protect, will power up until the speaker relays kick in after which it performs an immediate shutdown.
Checking the speaker terminals reveals -7.5volts on all terminals except for the Zone 2 channels.
All output transistors appear to be ok with no obvious shorts etc.
It looks like I have a floating ground somewhere however I'm just not sure where to start looking.
Any advice will be greatly... -
Re: New Members - please post your introductions here
Craig from Australia.
Just an electronics enthusiast that is learning how to fix all types of electronics.Leave a comment:
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