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6870QYC004B / 6870QYC004C / 6870QYC004D LG YSUS board - upgraded, tested, $40 credit for the old dud

Buy a serviced and tested LG YSUS board 6870QYC004C and send your old dud to get even better price

In stock


Coppell TV Repair LLC offers you a functional replacment for a defecive LG Y-sustain module 6870QYC004B / 6870QYC004C / 6870QYC004D as shown on the picture.

The board is used in a number of 50'' plasma TVs driven by LG plasma display technology. It is known under several other numbers such as 6871QYH039B.

The last letter denotes some minor differences in the PCBs used to produce the final product, but all three boards are compatible with each other.


You are purchasing a functional module that is same or 100% compatible with the one advertised in the subject of this listing.

Upon receiving and installing the module in your set you have the option to return your old malfunctioning dud and receive credit towards the purchase price shown here, subject to the below listed conditions.

The board you will receive can be brand new, used or, most commonly, a board serviced by us, Coppell TV Repair LLC.

Unless it is brand new (which is rare for the modules we offer as we specialize in servicing hard to find or expensive TV boards) it is guaranteed the board will be tested by our staff and there will be a label on it attesting to it.

Before placing an order please ensure that this is indeed the board in your set by comparing the number on it.

Failure symptoms

There are different ways the YSUS 6870QYC004B / 6870QYC004C / 6870QYC004D fail and there are therefore different manifestations of a failure.

It is important to remember that nobody can predict how exactly a board will fail and it is not necessary for your board to have failed in any of the ways described here; it can always be a unique or less popular failure.

With that in mind, here are the most common indications of a problem with the YSUS board:

1) Flashing display
Usually accompanied with "ticking" coming from the YSUS board, about once every second, in sync with the blinking display, this failure indicates one of the two large ICs on the board has failed.
We replace both ICs, though, since the still live one is not too far from failing either.

2) No image on display (black screen), sound possibly present
Sound is actually likely working fine even if you do not hear it as it is easy to lose proper input and therefore sound if you see nothing on the screen and start pressing buttons in hope to bring it back to life.

This is a typical YSUS failure symptom in many plasma TVs.

For double-checking it you may want to leave the TV to work for 4-5 minutes and test the temperature on the two heat sinks on the board - they should both be warm. If either heat sink is cold that indicates failed IC underneath.
The same test applies to the ZSUS board.

3) When powered on the TV clicks on followed by a quick click back off and never comes alive
While there are many possble reasons for this behavior there are just two in regards to the sustain boards: a blown fuse on the YSUS board (the ZSUS does not have its own fuses) or a failed and shorted sustain board (YSUS or ZSUS), but without having blown a fuse on the YSUS. Either condition would have the same result on the TV not willing to stay on.

Note 1: An open 4.0A fuse on the YSUS board does NOT automatically mean the board is bad! Since YSUS and ZSUS in 50HP66 are in parallel after the fuses it can be either one of them that caused the fuse to blow! 

Note 2: After confirming both fuses on the YSUS are good, you can try disconnecting the ZSUS from YSUS and try powering on again. If problem persists then ZSUS is probably not the source.

Note 3: You can use a digital multimeter to check each board's Vs to GND resistance on the power connector. A low resistance which is the same in both directions (Vs to GND and GND to Vs) indicates a faulty board.


Unless otherwise explicitly stated elsewhere in the listing the boards we sell come with a standard 90 days warranty.

Customer is responsible for return shipping and Coppell TV Repair LLC is responsible for shipping back to customer. Returned boards subject to exchange, service or refund, subject to availability and agreement by Coppell TV Repair LLC and customer.

Returned boards must carry the Coppell TV Repair LLC identification stamp or label and must not have been damaged, modified or otherwise tampered with in order for warranty coverage to remain in force.

Boards returned with request for refund / order cancellation will be subject to restocking fee covering forward shipping cost, transaction cost and $10 fee for the board testing needed prior to slating it for sale again.


Products will usually ship on the next business day after purchase is placed and paid. Unexpected delays may occur. If you do not receive a tracking number or message from us within 3 business days after purchasing please contact us.

When shipping method is specified during payment it is our first choice to utilize that method for shipping.
Yet sometimes it is not possible or may result in delays, e.g. a late Friday FedEx shipping of inexpensive and durable product may have a chance of being shipped in Friday than the following Monday; in such cases we reserve the right to substitute FedEx Ground with USPS Priority and, in some very rare cases, USPS First Class service. If shipping costs differ significantly you are in your right to contact and request price adjustment.

When shipping option for the order is "Free shipping" we will usually utilize cheapest available method.
See below for important disclaimer regarding the USPS First Class Mail packages.

    We do not advertise delivery time and do not take responsibility for delays to packages as long as tracking information proves they have been shipped in a timely manner by us.

    Be advised that the following delivery services are NOT insured per USPS policy:

    • Domestic: USPS First Class;
    • International: First-Class Package International™, Priority Mail International® Flat Rate Envelopes and Priority Mail International® Small Flat Rate Boxes; services to some countries may also not be covered, for details read the USPS article on the subject.

    What this means is that if you choose any of the above services as your delivery method you agree to hold us free of claims against loss of value should your package gets damaged or lost in the carrier system as long as the tracking information by the carrier shows the package was accepted by them and processed into their system.


    Upon receiving and installing the purchased module you can return your old one to receive the advertised credit.

    The credit will normally be issued as a partial refund towards your original payment; when this is impossible or inapplicable we may use other forms of payment such as PayPal or check.

    It takes 2-3 business days after the delivery of your board to us for it to be processed and the refund issued.

    In order to receive the full advertised credit the returned dud must meet all of the following conditions:

    1) It must be sent back within 14 calendar days of the delivery of the module you purchased from us, both per carriers' records. Make sure you keep your tracking number, you may need it!

    2) The board must arrive in good physical condition allowing subsequent electrical repair and reuse of the board. Sometimes when components fail and burn they also leave burn marks on the board. Most of the time such traces are not affecting the ability to restore the board's functionality, but in some extreme cases this may be a problem.

    3) The board must not have missing or replaced components or have otherwise been tampered with.

    Exceptions vary from all 3 listed conditions, but we reserve the right to be the judge on whether your board qualifies for an exception.

    If a board arrives that does not meet the above conditions and we do not consider it appropriate for extension we will contact you and offer you to get it back for the sole cost of the return shipping and/or offer you a trade-in price we consider reflecting its condition.

    The returned module must arrive in good physical condition and without previous traces of repairs or tampering in order to qualify for the full advertised credit.

    Modules that do not meet those criteria will be subjected to partial refund or no refund at all (depending on their condition and trade-in value).