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#101 |
New Member
Join Date: Jul 2020
City & State: Greenfield
My Country: United States
I'm a: Knowledge Seeker
Posts: 2
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![]() Just to add that for the D55u-d1, I only did it to one CPU, not two
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#102 |
Member
Join Date: Sep 2015
City & State: nyc
My Country: usa
I'm a: Knowledge Seeker
Posts: 24
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![]() Has a main board part interchange ever been determined? Just picked up an m50-c1 that needs a new board. Bad board is gxfcb0qk012040x / 715g7288-m02-000-005t.
Found https://www.tvpartstoday.com/756TXFC...fcb0qk0120.htm which lists "756TXFCB0QK0120 Vizio Main Board, 756TXFCB0QK012, 715G7288-M02-000-005T, GXFCB0QK012040X, GXFCB0QK012030X, GXFCB0QK012020X, CBPFETEKX6C, M50-C1" I do see that the d50u-d1's gxfcb0qk0220030x is much cheaper and more readily available. Looks like a similar board, but the picture shows the cn210 connector is populated on this model. edit: shopjimmy states "PLEASE NOTE: The main board you receive may or may not have connectors at locations CN210, CN212 and CN203. These connectors are not used in model M50-C1 and will not affect functionality. " Last edited by ziddey; 05-24-2021 at 07:27 PM.. |
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#103 |
Badcaps Veteran
Join Date: Sep 2020
City & State: Guelph
My Country: Canada
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 232
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![]() I can see that D50u-D1 has much better heatsink construction and I think springs are used to hold it down. Basically the springs should provide even pressure between heatsink and chips and maintain it even if board is flexing.
I thought about this previously and modified M43-C1 heatsink. I removed all pins and put 4 M2 screws/nuts and springs in between. This has been running for 2-3 months, will see how long it will last. At least seeing these D50u-D1 boards available means that they don't fail as badly as M's. |
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#104 |
Member
Join Date: Sep 2015
City & State: nyc
My Country: usa
I'm a: Knowledge Seeker
Posts: 24
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![]() While looking for a replacement board, I threw the old one in the oven.
Preheated to 425'f, and then tossed it in. Cut the heat after 6 minutes, and cracked the door after 10. Waited half an hour (way too little time) and gave it a go. Guess the tv works for now... |
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#105 |
Member
Join Date: Sep 2015
City & State: nyc
My Country: usa
I'm a: Knowledge Seeker
Posts: 24
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![]() Just realized the coax soldered itself shut in the oven.
![]() Got it opened back up, but not without completely melting and making a mess of the plastic insulation. Seems to be working now though.. Might not be a bad idea to stick a paper clip or similar in the coax port before putting it in the oven. It'd be a lot easier to desolder that than to try and clean out the port otherwise. Maybe it'd have been possible to flow out working from the inside, but I didn't feel like taking the tv apart again. Last edited by ziddey; 05-30-2021 at 08:10 PM.. |
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#106 |
New Member
Join Date: Jun 2021
City & State: Berlin, Md
My Country: usa
I'm a: Knowledge Seeker
Posts: 3
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![]() Hoping someone can help me find the value of, or hook me up with the smd ceramic capacitor on the back of the main board at position C478 (backside/middle of board). I knocked it off and lost it after removing the heat sink on XFCB0QK003020Q.
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#107 | |
New Member
Join Date: Dec 2020
City & State: Albany
My Country: United States
I'm a: Knowledge Seeker
Posts: 10
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200F preheat 6 min 350F for 3.5 min 450F for 4 min That replacement board I got didn't work. Not sure if it's DOA or if it's not the right one. I for sure should have tested it when it arrived but it never felt worth it to take the tv apart when it was working ![]() |
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#108 |
New Member
Join Date: Dec 2020
City & State: Albany
My Country: United States
I'm a: Knowledge Seeker
Posts: 10
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![]() I kept trying more aggressive profiles until the connectors started melting. Each time the TV would come back to life for a few hours then die. I kinda wonder if the thermal grease on the heatsink stopped working after being in the toaster so many times.
I then tried a more proper reflow: I chopped off the heatsink and tried a reflow with my hot air SMD station, but I busted an inductor along the way. Nothing happens now with the original main board. I'm throwing in the towel and bought a TCL 635. Overall I'm happy that the toaster oven thing gave 8 months of extra life on the TV. It meant I got to get a 2021 model TV instead of a 2020 (though TVs are super expensive right now with the chip shortage). Thanks everyone for their ideas and camaraderie! Good luck fixing your TVs! |
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#109 |
Member
Join Date: Jun 2017
City & State: Seattle WA
My Country: United States
I'm a: Knowledge Seeker
Posts: 50
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![]() Saved another one with reflow oven 375F(laser temp gun shows board slightly hotter)/8min. This time a P502UI-B1E (2nd one repair by this method). circa 2015 50" Vizio UHD.
Checked PSU and got 12V (standby voltage on this model) and saw PS_ON trigger with power on. Then onto Betty Crocker. Works again for the time being. Toaster oven is batting 4 for 4 so far. 3 Vizio TVs with main boards of this general design and a Nintendo Switch. TVs gets pretty light use and Switch probably gets the most use and still going after 8-9mo. On these Vizio main boards, I think its really important to remove the heat sink but it is crazy hard without the right tools. What I use is - Hakko FR-301 powered suction desoldering tool on fairly high temp - Soldering gun (ex Weller D-650) 2 people, 4 hands, 2 heating devices, lower post melting temp with leaded solder (low melt solder probably even better). If we had a bigger opening diameter tip for the Hakko to go completely around the heat sink post, might have been able do the job alone. Standard tips don't wrap around this big posts. I also found the thermal paste completely dried and hardened on this one. Took while to even get it off.. hardest I've ever seen. So part of the repair longevity is probably fresh thermal paste which is only possible with heat sink removal. Not saying this is the proper fix but prob best most DIYer can do without access to BGA reflow station. Last edited by howardc64; 08-10-2021 at 01:55 AM.. |
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#110 | |
New Member
Join Date: Jun 2021
City & State: Berlin, Md
My Country: usa
I'm a: Knowledge Seeker
Posts: 3
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#111 | |
Member
Join Date: Jun 2017
City & State: Seattle WA
My Country: United States
I'm a: Knowledge Seeker
Posts: 50
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I tried some small fans with original heat sink but it didn't move much air at reasonably low audible RPMs. Also can't mount it to provide good cooling. The original heat sink don't have much room for any good solution. But custom heat sinks need to have secure contact to the chip surface and original heat sink mounting holes aren't perfect for the job. A combined custom heat sink such as you are attempting might provide a solution. Sorry but I gave up on forced air cooling after a brief attempt. |
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#112 |
New Member
Join Date: Jun 2021
City & State: Berlin, Md
My Country: usa
I'm a: Knowledge Seeker
Posts: 3
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![]() I'm currently looking at making adjustable threaded plastic stand-offs to avoid whatever v+ continuity I had with the metal ones preventing the tv from booting. This will allow me to use the best cooling solution I have atm, the Asus fan blowing between the HS and the board. BUT, it's a 12v fan and I'd like to use a switched 12v point on the board, if there is one. maybe howardc64 could advise of a spot on M43 board or unit that has switched 12V.
A waterblock would likely be the best one could hope for, I'm sure alibaba or Banggood type places would have an afordable option. Might even really add longevity after a good reflow. Also, when using flux and trying to get it under the chips, only apply on 3 sides to avoid a vaper lockout thing. As advised by knowledgeable youtuber.. |
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#113 | |
New Member
Join Date: Dec 2021
City & State: Lakeway
My Country: United States
I'm a: Knowledge Seeker
Posts: 2
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![]() Quote:
I just reflowed one of these board in a toaster/reflow oven with a controller I built a while back to reflow small prototype boards, and the TV has been running for a couple of days now, will see how long it lasts. I heated the board to 50C for a minute, then ramped up to about 170C, another couple of minutes to get there, when raised up to 190C, but because thermal inertia the temperature on the board continued going up and got up to about 210C at the heatsink, stayed there for a minute or so and started going down slowly. My controller uses a thermocouple I normally just keep close to the PCB, but in this case since I didn't remove the soldered heatsink, only the rubber pads on both sides. I put the thermocouple in a hole the heatsink had, hopefully to ensure the reading would match the temp at the ICs closely. Posting in case it helps anyone reading this thread. |
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#114 | |
Member
Join Date: Jun 2017
City & State: Seattle WA
My Country: United States
I'm a: Knowledge Seeker
Posts: 50
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#115 | |
Member
Join Date: Sep 2015
City & State: nyc
My Country: usa
I'm a: Knowledge Seeker
Posts: 24
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![]() Quote:
Updating on this. The oven treatment only worked for a few months, and I ended up giving this part a shot. Received GXFCB0QK012030X, which has two additional connectors compared to the original 12040x. Working well. |
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#116 |
Badcaps Veteran
Join Date: Nov 2015
City & State: BC
My Country: Canada
I'm a: Knowledge Seeker
Posts: 1,341
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![]() Ebay seller kcrownie repairs this board now. I have used him before for Samsung F model year boards and some LG boards before with no issues.
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#117 | |
New Member
Join Date: Dec 2021
City & State: Lakeway
My Country: United States
I'm a: Knowledge Seeker
Posts: 2
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#118 |
New Member
Join Date: Jan 2014
City & State: Atlanta, Georgia
My Country: USA
I'm a: Knowledge Seeker
Posts: 1
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![]() Just to add a data point: My M43-C1 had this same issue, and I replaced it with a D50u-D1 main board and it works perfectly; no modifications needed.
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