logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda

Samsung Xcover 3 G388F Touch Issue - Non-Working Touchscreen After Fall, Need Diagram

max_gsm 8847 14
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Report a violation of the law
| New topic
  • #1 16676220
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    Hello, how the topic does not work on the Samsung Xcover 3 G388F.
    The touch is functional because after switching to another phone, everything works as it should. The telephone after the fall, was not flooded, no traces of liquid.
    Maybe some of your colleagues have a diagram for this model.
    Thank you in advance for your help.
  • ADVERTISEMENT
  • #2 16676496
    KamGr
    Level 24  
    Posts: 836
    Help: 77
    Rate: 203
    Have you tried hard reset? I had it too and it helped me.
  • ADVERTISEMENT
  • #3 16676523
    KRY5PIN
    Level 37  
    Posts: 3010
    Help: 312
    Rate: 463
    The phone was down. It has not been damaged or has not dropped February on the LCD where the digitizer is attached ??
  • #4 16715409
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    Resetting did not help, and whether it was after a fall is difficult to say because it looks like new, without mechanical damage, but if you connect the digitizer to another disc it's all oki, i.e. the damage is on the disc. Maybe someone knows which element is responsible for touch in this model?
  • #5 16735165
    marrt
    Level 15  
    Posts: 120
    Help: 16
    Rate: 14
    max you managed to activate the touch, I have a similar case after the exchange of touch no response to touch
  • #6 16735249
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    I just failed but I already know what the problem is, I can take photos and describe what and how. If someone had a diagram for this, I think there would be no problem with repair.
  • ADVERTISEMENT
  • #7 16735273
    mahamalak
    Level 12  
    Posts: 167
    Help: 2
    Rate: 110
    Find the schematic and check the layout responsible for the touch, it will probably be replaced.
  • #8 16735289
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    There's a problem with the schematic for this model, I can't find anywhere unless you know which system is responsible for the touch.
  • #9 16735363
    marrt
    Level 15  
    Posts: 120
    Help: 16
    Rate: 14
    max if you can make a short description based on your photos
  • ADVERTISEMENT
  • #10 16742438
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    At the request of "marrt" and for everyone who has a similar problem with touch I made a small description. In the photo there are three very important resistors, each of them should have a value of 2.2 KoHm, if one does not, or its resistance changes, then the touch will not move and as I described in the photo on each of them must be 1.8V .
    If there is no such voltage on one of them, then the touch will not move, and umnie is so that everywhere I have a voltage of 1.8 V except in the one where it is marked with a yellow line, for me on the other side of the resistor is only 0.7 V and therefore touch doesn't work. I can't trace where this resistor is going because it looks as if something is occupied and this 1V is lost. If it turns out that there is no voltage at all on any of these resistors then you need to replace one more element that is on the other side of the board. I hope that this description helps someone put a problem with touch, and maybe someone comes to where this resistor is marked in yellow. Samsung Xcover 3 G388F Touch Issue - Non-Working Touchscreen After Fall, Need Diagram
  • #11 16745540
    Glemark1
    GSM specialist  
    Posts: 1204
    Help: 190
    Rate: 111
    In the picture I have marked all the lines responsible for touch.
    Resistors are resistors that pull up data lines, clock etc. to power 1.8 in accordance with the I2C bus specification.
    Samsung Xcover 3 G388F Touch Issue - Non-Working Touchscreen After Fall, Need Diagram
  • #12 16749734
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    Many thanks to "Glemark1" for the schematic, everything is fine with me and the touch still does not work because the TSP_CLK line voltage on the resistor disappears, instead of 1.8 V I have only 0.7V, I do not know where this line goes because that is the whole problem.
  • #13 16749837
    Glemark1
    GSM specialist  
    Posts: 1204
    Help: 190
    Rate: 111
    On the other side of the resistor you will not have 1.8V because there is a generated waveform. Connect the oscilloscope and you'll see. This signal is generated directly by the processor.
  • #14 16749876
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    I checked on the second board which is fully functional and is 1.8V on both sides of the resistor and on both.
  • #15 16796784
    max_gsm
    Level 18  
    Posts: 429
    Rate: 42
    Unfortunately I could not cope with this fault, the motherboard went to parts. Thank you for your help in the subject.
| New topic
Report a violation of the law

Topic summary

✨ The discussion revolves around a Samsung Xcover 3 G388F experiencing touchscreen issues following a fall. The user confirmed that the touchscreen works when connected to another device, indicating the problem lies within the phone itself. Suggestions include performing a hard reset, checking for mechanical damage, and examining the digitizer connection. A follow-up revealed that the issue may be related to specific resistors on the board, which should measure 2.2 kOhm and have a voltage of 1.8V. A schematic diagram is sought to assist in troubleshooting, with users sharing insights on the importance of voltage levels across components. Ultimately, the original poster was unable to resolve the issue, leading to the motherboard being deemed irreparable.
Generated by the language model.

FAQ

TL;DR: On the Xcover 3 G388F, 3 pull‑up resistors (2.2 kΩ) must each read 1.8 V; “touch will not move” if one is low. [Elektroda, max_gsm, post #16742438] Why it matters: This FAQ helps phone repairers quickly diagnose no‑touch after a drop by checking the exact lines and voltages.

Quick Facts

How do I fix a Samsung Xcover 3 G388F touchscreen that stopped after a fall?

Check the three touch pull‑up resistors. Each should be 2.2 kΩ and show 1.8 V on both ends. If any reads low, trace that line and restore 1.8 V. If 1.8 V is missing on all, inspect the related element on the board’s other side. Verify continuity to the connector. Finally, test TSP_CLK with a scope for a valid clock. [Elektroda, max_gsm, post #16742438]

Where are the critical pull‑up resistors and what values should they read?

They are three highlighted resistors in the touch section. Each must measure 2.2 kΩ and have 1.8 V present during operation. If one drifts or opens, the touchscreen remains unresponsive. “On each of them must be 1.8 V.” [Elektroda, max_gsm, post #16742438]

What voltage should I expect on the touch lines (data/clock)?

Expect 1.8 V logic on the pull‑ups feeding the I2C touch lines. Measure both sides of each 2.2 kΩ resistor; healthy boards show about 1.8 V referenced to ground. Loss of this bias prevents the panel from initializing and tracking touches. [Elektroda, max_gsm, post #16742438]

What is TSP_CLK on the Xcover 3, and why does it matter?

TSP_CLK is the touchscreen clock line. It is generated by the processor and should show a waveform on the IC side. If the line is flat or low under load, touch will not function. “This signal is generated directly by the processor.” Verify with an oscilloscope at the pull‑up and at the SoC pad. [Elektroda, Glemark1, post #16749837]

How do I check TSP_CLK with an oscilloscope?

Probe the resistor that pulls up TSP_CLK. On the processor side, you should see an active clock waveform. On a healthy board, you also read about 1.8 V DC bias. If you only see DC or a depressed level, trace toward the processor for faults. [Elektroda, Glemark1, post #16749837]

Why does one resistor show only ~0.7 V and the touch is dead?

A depressed reading like 0.7 V indicates the pull‑up is loaded or the line sinks current. The poster observed 0.7 V on the TSP_CLK side and the touch failed. Remove shorted components or repair the trace to restore the 1.8 V level. [Elektroda, max_gsm, post #16742438]

Can a hard reset resolve a non‑working touchscreen on this model?

Yes. One technician reported that a full hard reset restored touch responsiveness on the Xcover 3. It is quick to try before board‑level work. Back up data first, then reset and retest. [Elektroda, KamGr, post #16676496]

Is my digitizer bad if it works on another phone but not on this board?

No. If the digitizer responds when connected to a different mainboard, the fault is on your original board. Focus on pull‑ups, the 1.8 V bias, and clock line integrity to the connector. [Elektroda, max_gsm, post #16715409]

Do we have a touch line map or schematic reference for the G388F?

Yes. A contributor marked the touch‑related lines and noted that the resistors are pull‑ups for I2C data and clock to 1.8 V. Use this map to follow signals from the connector back to components. [Elektroda, Glemark1, post #16745540]

What is I2C in this touch context?

I2C is a two‑wire interface with data (SDA) and clock (SCL) lines that require pull‑ups to a logic rail. In this phone, the touch lines are pulled to 1.8 V through the noted resistors, enabling communication with the controller. [Elektroda, Glemark1, post #16745540]

I replaced the touch panel but still get no response—what should I check next?

Confirm the three pull‑ups are 2.2 kΩ and have 1.8 V. Then check continuity from connector pins to each resistor and the TSP_CLK source. If bias and continuity are good, validate the clock waveform at the processor side. [Elektroda, Glemark1, post #16745540]

Could missing 1.8 V be due to another faulty part on the board?

Yes. If 1.8 V is absent on all three resistors, the poster advises replacing an additional element on the opposite side of the board. Restore that rail first, then retest touch. [Elektroda, max_gsm, post #16742438]

What’s an example of a repair that still fails even after checks?

One case documented all checks and still failed to restore touch. The board was ultimately dismantled for parts, indicating a deeper, uneconomical fault. Use this as a stop‑loss benchmark. [Elektroda, max_gsm, post #16796784]

How can I quickly test the three pull‑ups without full disassembly?

With the phone powered, place the black lead on ground. Probe both ends of each marked 2.2 kΩ resistor. Expect about 1.8 V on each end. Any low reading flags that signal for deeper tracing. [Elektroda, max_gsm, post #16742438]

What are typical healthy readings versus a faulty board?

Healthy board: ~1.8 V on both sides of each pull‑up. Faulty case reported: only ~0.7 V on the TSP_CLK side, causing no touch. That statistic distinguishes a good rail from a loaded line. [Elektroda, max_gsm, post #16749876]

Can I rely on DC voltage alone, or must I scope the clock?

Use both. DC checks catch missing 1.8 V bias, but only a scope confirms a valid clock. As one expert said, “This signal is generated directly by the processor,” so waveform presence matters. [Elektroda, Glemark1, post #16749837]
Generated by the language model.
ADVERTISEMENT