Why has no reply been posted on Dell’s Chinese official website forum?

Hi

""Post this service, the external monitor still flickered black every time my coffee machine powered on, a clear sign of flawed power isolation/grounding circuitry on the original motherboard.""

To me that is either a poor power circuitry, or more likely a mains spike, or a brown out. 

SURGE PROTECTION recommended, and possibly the building wiring..

AI/LLM is slightly more eloquent....

Ground Loops: When the PC and monitor are on different circuits, ground potential differences create interference. A quick diagnostic is to plug both devices into the same power strip; if flickering stops, a ground loop is confirmed.

EMI Sources: High-power appliances like coffee machines can inject noise into cables. Using ferrite cores on cables or moving data cables away from power lines can help mitigate this.

Power Quality: Using a UPS with line conditioning or ensuring all equipment is on a properly grounded circuit can resolve instability caused by voltage spikes or drops. 

IMHO laptops are more likely to suffer from poor electrical supply (even with a battery to smooth things out) than a Desktop that can stifle spikes and brown-outs a little better.

I note you do not explain the 2nd repair very thoroughly... ""I paid a third-party vendor for inspection, which confirmed damaged memory slots and defective motherboard hardware. The repair was only a temporary fix; the USB 2.0 port remained non-functional afterward.""

Was the Main (Mother) board changed at this point, or something else?  

Because the 3rd repair '"I self-funded a full motherboard replacement via an independent repair shop.'"  ""This firmly verifies the notebook suffered factory-originated motherboard circuit defects and defective power isolation""

I disagree with the sweeping statement about the original factory motherboard, as having 2 prior repairs, it is not known the extent of those repairs.

YES I accept you have grievances, and hopefully a Moderator will pass your case/concerns on, but this is a community forum of very random people, the majority not Dell employees.

So please try and accept that you now have a good laptop and bad memories, and move on.

@anne_droid​ 
 First thank you reply.

@anne_droid​ 

Hi.

Sorry, there was an error with the link just now. Here is the correct response regarding the repair process.<To protect you, your private information was removed from public view. All private data was saved to your private Case. DELL-Admin>

part imp:
Timeline of Failures 1. July 26, 2022 (In-warranty): First failure (unable to boot); Dell only performed static discharge with no part replacement
2. December 26, 2025 (Out-of-warranty): Second failure; third-party inspection identified damaged motherboard memory slots
3. May 2, 2026 (Out-of-warranty): Third failure; total motherboard failure with permanent blank screen.
niuchunguo

@niuchunguo​ Most of tech support does not have access to the old system so they more than likely will be unable to view older service request details. To this extent, Support would be correct in that previous history may not be retrievable. That said, I do have this access and taking a look at the initial in-warranty work order notes, they indicate that the technician did indeed replace the motherboard for your initial issues. The purpose of a warranty is to define a product support period. If issues were unresolved after the initial repair, then they would have needed to of been addressed within the warranty period. If your system is out of warranty, then any repairs would need to be purchased at that time. Dell would not be responsible for any 3rd party repairs or assessments. 

@DELL-Daniel V​ 

HI. DELL-Daniel V

First of all, thank you for your sincere reply and the confirmation information you provided regarding the motherboard replacement carried out under warranty. The original statement reads: they indicate that the technician did indeed replace the motherboard for your initial issues.

I would like to further elaborate on this case and appreciate your continued support!

Overview of Fault Repairs

• First Failure (Within Warranty, July 2022): Black screen, unable to power on. Dell’s after-sales service either resolved the issue via static discharge or replaced the motherboard — these two statements are contradictory, though you have now confirmed a motherboard replacement took place. However, after the repair, the screen still flickered black when an external monitor was connected and a coffee machine was turned on. This symptom points to an underlying hazard in the motherboard’s power isolation/earthing circuit. As you initially analyzed regarding power supply EMI noise sources: high-power appliances such as coffee machines can inject electrical noise into power cables, which can be mitigated by fitting ferrite cores on the cables. Crucially, under the exact same operating environment, an HP ENVY 460 and a ThinkPad operated without any issues. The flickering black screen issue vanished entirely after I personally paid to install an i5 7510 motherboard in the third repair round.

• Second Failure (December 2025, Out of Warranty): Identical black screen failure. As you stated: If your system is out of warranty, then any repairs would need to be purchased at that time. Dell would not be responsible for any 3rd party repairs or assessments. I fully understand all out-of-warranty repairs are at the owner’s cost, so I sent the device to my supplier for paid third-party inspection. The technician identified a damaged memory slot, one faulty memory stick, and a non-functional USB 2.0 port. Since a full motherboard replacement carried a high price tag, I opted to remove the defective memory module and disregard the failed USB 2.0 port to continue using the machine. No formal repair was completed on this occasion; only the faulty memory stick was removed following inspection.

• Third Failure (May 2, 2026): Exact same black screen, no power-up. I paid for a third-party replacement of an i5 motherboard, after which the long-standing flickering black screen when activating the coffee machine with an external display connected disappeared completely.

This identical fault has occurred three times in sequence, and the issue was fully resolved only after fitting an i5 replacement motherboard.

Technical Analysis

All three failures presented identical symptoms with no change in user experience until the third motherboard swap to an i5 unit eliminated every fault. This confirms the device suffered from an unresolved hardware defect for five years, detailed below via fault logic analysis:

1. Analysis 1 – Interpretation of the first motherboard replacement The original i7 motherboard and the warranty replacement i7 motherboard exhibited identical persistent faults and identical failure patterns across three breakdowns, while the i5 motherboard operates flawlessly. This strongly suggests both i7 motherboards share the same inherent flaw, indicating a potential batch quality defect specific to i7 model motherboards. The units operated with latent faults that progressively worsened until total hardware failure, and there is a clear difference in earthing design between these i7 boards and the replacement i5 motherboard.

2. Analysis 2 – Interpretation of the static discharge troubleshooting If the first service visit only performed static discharge without hardware replacement, the exact same recurring faults across three incidents still persisted unchanged until the i5 motherboard swap. This implies the original i7 motherboard carried the root defect from the outset, with fault severity escalating after the warranty expired — the visible damage manifested as a faulty memory slot and defective RAM, allowing limited operation after removing the bad memory stick, followed by total motherboard failure in the third breakdown. This again confirms the original i7 board ran with an unresolved progressive fault, with distinct earthing characteristics compared to the i5 replacement.

3. Analysis of static discharge in relation to the second repair One interpretation claims the static discharge reference refers to the second failure, yet the second breakdown was handled entirely by an independent third party with no Dell service involvement. How can Dell confirm that static discharge was the troubleshooting step performed by this external vendor?

4. Ambiguity in Dell’s wording regarding static discharge Cross-referencing supporting documentation yields conflicting interpretations: the AI tool Doubao associates the static discharge description with the first repair, while DeepSeek links it to the second. The ambiguous phrasing in Dell’s official email creates two possible readings, both damaging to Dell’s position:

   • If Dell now asserts the static discharge notation refers to the second repair (citing formal records of hardware replacement on the first visit): this inadvertently validates Analysis 1, confirming two defective i7 motherboards with shared identical faults and substantiating suspicions of batch-wide quality defects.
   • If the static discharge notation originally referred to the first repair (my position aligned with Doubao’s analysis): Dell previously claimed no hardware repair was performed under warranty, framing static discharge as a non-hardware fix to argue the three breakdowns stemmed from separate unrelated issues and avoid liability. This stance directly contradicts later email records confirming a motherboard swap on the first service visit, eroding Dell’s credibility while failing to absolve them of responsibility — it still proves two faulty i7 motherboards with persistent unresolved manufacturing defects.

Core Questions

Three identical recurring failures conclusively demonstrate the device shipped from the factory with an inherent motherboard circuit flaw and defective power isolation design, which Dell’s in-warranty service never fully rectified.

I have five decades of professional experience working in the ICT industry, with comprehensive expertise in power isolation, earthing architecture, and the relationship between three-pin plug protective earth and equipment functional ground. The flickering external display when the coffee machine activates, plus the tingling electric sensation on the chassis, unequivocally stem from a broken connection between the device casing and the mains protective earth.

The consistent fault performance on two separate i7 motherboards paired with full resolution on an i5 motherboard eliminates my home power supply and operating environment as root causes. Supporting documentation including schematic diagrams and original photographs of my residential setup is available on the website for verification.

Given the persistent flickering screen defect remained after the in-warranty i7 motherboard replacement and vanished entirely after my aftermarket i5 motherboard swap, I have reasonable grounds to suspect a widespread batch defect affecting this series of i7 motherboards, a conclusion also supported by batch quality analysis generated via Doubao AI.

1. Why did Dell initially claim static discharge does not constitute hardware repair, attempting to argue the original unit had no manufacturing fault and dismiss the three identical recurring failures as unrelated issues to evade liability?
2. Why did Dell later revise their statement to confirm a full motherboard replacement was completed under warranty, framing the service as a complete resolution to argue any post-warranty damage is the customer’s sole financial responsibility?
3. During our email correspondence, I brought up the issue that **the external display would flicker and cut to black whenever I turned on the coffee machine**. The Dell China technical support staff asked me, "Are you certain about this?" I confirmed the issue, yet they never brought the matter up again afterward. I believe they knew the root cause but were unwilling to acknowledge it openly.
4. When I requested access to the original warranty service records, Dell claimed system upgrades rendered the records unavailable — this contradicts their own email correspondence explicitly stating the service history was retrieved: they indicate that the technician did indeed replace the motherboard for your initial issues.
5. Following confirmation of the first in-warranty motherboard swap, what underlying defect plagued the original factory-fitted i7 motherboard? Dell must hold this information. The second i7 motherboard developed a faulty memory slot, operated temporarily after removing damaged RAM, then suffered total catastrophic failure. The chassis tingling and flickering screen persisted without exception from new device setup through both i7 motherboard lifecycles, only disappearing after switching to the i5 unit. What does the identical fault behavior across two i7 motherboards prove, and what does the full resolution on the i5 motherboard confirm?
6. Whether the flaw lies in the i7 motherboard hardware itself or non-compliant earthing connections during assembly, only Dell possesses full transparency on this matter.

I wish you luck.

@niuchunguo​ I am unable to view the site links being shared. As mentioned, most of Tech Support no longer has access to the older system, so they are unable to retrieve any older details. The initial work order notes indicated your system had no power so the board was replaced for that. There are no reported known issues for the Vostro 7510 regarding external video or power that I can see. Further more, the original motherboard and the replacement motherboard were slightly different revisions, so they would not be of the same batch. If the flicking screen issue remained unresolved after the first in-warranty repair then it should have been reported to tech support at that time for further troubleshooting. As anne_droid said, this likely would stem from dirty power draw. Dell would be unable to account for all power scenarios. I would not be certain what would be the differences between an i5 and i7 board would be, but you can assume the i7 had more power draw. As the unit is out of warranty and nearly 5 years old, Tech Support would be unable to investigate an issue like this much further.

@DELL-Daniel V​ 
 

Can you read Chinese? Please try to access this port to retrieve more information. It contains extensive materials in both Chinese and English

Evidence of Contradictions and Liability Evasion

Prior to the first repair, instead of inquiring about the machine malfunction and actively resolving it, Dell emphasized irrelevant issues unrelated to the repair. Does lack of ownership proof justify denying repair? (I registered and activated the machine on Dell's official website immediately after purchase)! Is this not evasion? Screenshot of the original email for Dell's factory machine registration is as follows:

Screenshot of the original email highlighting irrelevant content on July 22, 2022:

When I raised concerns about three identical malfunctions suspected to be a batch quality issue during this repair, Dell began emphasizing that the machine had no prior repair records.
Email from Dell to NCG on May 6, 2026, emphasized:
There are no corresponding hardware repair records in the system (referring to the unbootable issue reported on July 25, 2022 (within warranty period) and sent for repair; resolving it via "electrostatic discharge is not considered hardware repair"). See original email screenshot as follows:

Email from Dell to NCG on May 14, 2026 (Ultimate after-sales service opinion):
The first report of unbootable issue on July 25, 2022 (within warranty period) was resolved after Dell's official after-sales testing and "motherboard replacement". See original email screenshot as follows:

Why are there contradictory statements in different periods? The email content is clearly inconsistent—what is the purpose?

Personal Assessment Based on the Above

• The "external screen black flickering when coffee machine is turned on" is likely the trigger for frequent recurrent faults. Dell once asked "Are you sure?" in an email, to which I confirmed. The phenomenon no longer recurred after motherboard replacement. Reviewing Dell's original email regarding the July 26, 2022 warranty repair: no parts were replaced at that time, only electrostatic discharge was performed! Question: The three malfunctions occurred in July, December, and May respectively—why would static electricity be more prevalent in summer and cause faults? The phenomenon disappeared after motherboard replacement, clearly indicating that the first issue was not truly resolved; only simple electrostatic discharge was done, without investigating the root cause of summer static electricity leading to crashes!
• Combined with the "static electricity theory", it can be inferred: Defects in the motherboard's power isolation caused static accumulation; the device worked temporarily after the first electrostatic discharge; the second malfunction damaged the memory slot, one memory stick (and USB2.0 port), and the device worked temporarily after removing faulty parts; the third malfunction caused complete motherboard failure!
• Regarding the compatibility issue between the USB3.x port and Ugreen hard drive enclosure: on the surface, it seems to be Ugreen's incompatibility, but Ugreen actually upgraded the hard drive enclosure firmware for me. Both are well-known manufacturers, and the liability for compatibility issues should be determined objectively!
• In summary, based on my 50 years of experience in radio (linear circuits) and ICT industry, I judge: At the very least, the power isolation of this motherboard is highly likely to have defects.