Member Avatar for planetrock

After disassembling my Presario 2100 to resolder the DC jack, the computer no longer recognizes the touchpad, and the LEDs for 'on/standby' and 'battery charging' no longer work.

Strangely, the LED for hard-drive activity does work.

The touchpad ribbon cable is connected. I am 99.999% it is seated all the way because I triend re-inserting it many times.

External PS/2 mouse works just fine.

In the Control Panel > Mouse there is no choice for touchpad, only the PS/2 mouse (when it's attached).

*However* - in the Properties and other tabs, it says 'Synaptics TouchPad Properties Version 6.7.4' etc. and clicking on 'Settings' brings up the Synaptics window, which is what you would see when the touchpad was working. But instead of having all the advanced settings for touchpad features, it says 'Properties for Standard Mouse on PS/2 Port'.

There were never any problems or unusual behavior with the touchpad before.

I went into BIOS Setup and reset everything to the defaults.

What could be going on here? Could I have physically damaged anything? I have disassembled the laptop a couple times to clean out the fan and replace the keyboard, with no problems.

many thanks

system:
Compaq Presario 2100 AMD
XP
40Gb, 756 Mb RAM
3 or 4 years old

  • 7 Contributors
  • 8 Replies
  • 2K Views
  • 5 Years Discussion Span
  • Latest Post Latest Post by PRAKASHOM9095

Dani AI

Generated

Good clues in your symptoms, and . After a DC‑jack rework, a dead touchpad plus missing power/charge LEDs (while the HDD LED still blinks) almost always points to a top‑cover cabling issue, not a driver. On the Presario 2100’s Quanta KT7I board, the embedded controller (KBC) handles the touchpad’s PS/2 clock/data lines (TPCLK/TPDATA) and also drives the front‑panel status LEDs (-PWRLED, -BATLED0/1, -HDDLED). If the HDD LED works, the KBC is alive; focus on the flex cables between the top cover and system board (touchpad FFC and the small power/LED board cable). (s-manuals.com)

What I would do quickly:

  • Power removed and battery out. Reseat the touchpad FFC at both ends. Fully open the ZIF latch, insert to the alignment line, make sure the exposed contacts face the connector’s contacts, then lock it. ZIFs come in top‑contact, bottom‑contact, or dual‑contact variants; inserting upside‑down or with a half‑closed latch produces the exact “standard PS/2 mouse only” behavior you’re seeing. (te.com)
  • Inspect the FFC near any bend/crease for hairline cracks. is likely right: these traces fracture easily. Replacing the cable is safer than trimming/scraping as did (that fix can work, but it is easy to over‑sand and ruin more conductors).
  • With a multimeter: check continuity across the FFC for four essentials (TPCLK, TPDATA, Vcc, GND). Then power on and verify you have ~5 V at the touchpad connector (PS2_VCC on this platform). Any open line or missing Vcc points to a bad cable or an upstream filter component. (s-manuals.com)

For the LEDs, reseat/replace the small front status/power‑button cable first. Those LED lines are separate in the schematic, so a misseated or damaged LED board/cable can kill the power/charge LEDs while leaving the HDD LED fine. If cables check out and 5 V reaches the touchpad but it is still absent, suspect a failed touchpad board or ESD/protection parts near the KBC from heat during the DC‑jack repair. At that point, board‑level work or part replacement is the practical path. (s-manuals.com)

Recommended Answers

All 8 Replies

Member Avatar for H2oWorm

After disassembling my Presario 2100 to resolder the DC jack, the computer no longer recognizes the touchpad, and the LEDs for 'on/standby' and 'battery charging' no longer work.

Strangely, the LED for hard-drive activity does work.

The touchpad ribbon cable is connected. I am 99.999% it is seated all the way because I triend re-inserting it many times.

External PS/2 mouse works just fine.

In the Control Panel > Mouse there is no choice for touchpad, only the PS/2 mouse (when it's attached).

*However* - in the Properties and other tabs, it says 'Synaptics TouchPad Properties Version 6.7.4' etc. and clicking on 'Settings' brings up the Synaptics window, which is what you would see when the touchpad was working. But instead of having all the advanced settings for touchpad features, it says 'Properties for Standard Mouse on PS/2 Port'.

There were never any problems or unusual behavior with the touchpad before.

I went into BIOS Setup and reset everything to the defaults.

What could be going on here? Could I have physically damaged anything? I have disassembled the laptop a couple times to clean out the fan and replace the keyboard, with no problems.

many thanks

system:
Compaq Presario 2100 AMD
XP
40Gb, 756 Mb RAM
3 or 4 years old

I'm having the EXACT same problem. Does anyone have a solution?

Please help.

please e-mail to

THANKS!

Member Avatar for H2oWorm

HELP!

PLANETROCK, have you rec'd any e-mail responses on this or did you figure out what the problem was?

Member Avatar for planetrock

neither


nor did I get any replies at other laptop repair forums where I posted the same message: TechSupportGuy, AskLaptopFreak, HP...

Member Avatar for jbennet

i have the same problem on a thinkpad but with the little ball mouse thing

Member Avatar for rmrd

Often times, these cables are fragile and you could've easily broken some of the copper connectors on the inside of the cable by bending it on removal or re-insertion.

Given all the other facts of the situation, this is likely the case. Look into purchasing a replacement cable -- though an entire top assembly for your model laptop on eBay would probably be cheaper.

Member Avatar for karunadheera

After disassembling my Presario 2100 to resolder the DC jack, the computer no longer recognizes the touchpad, and the LEDs for 'on/standby' and 'battery charging' no longer work.

Strangely, the LED for hard-drive activity does work.

The touchpad ribbon cable is connected. I am 99.999% it is seated all the way because I triend re-inserting it many times.

External PS/2 mouse works just fine.

In the Control Panel > Mouse there is no choice for touchpad, only the PS/2 mouse (when it's attached).

*However* - in the Properties and other tabs, it says 'Synaptics TouchPad Properties Version 6.7.4' etc. and clicking on 'Settings' brings up the Synaptics window, which is what you would see when the touchpad was working. But instead of having all the advanced settings for touchpad features, it says 'Properties for Standard Mouse on PS/2 Port'.

There were never any problems or unusual behavior with the touchpad before.

I went into BIOS Setup and reset everything to the defaults.

What could be going on here? Could I have physically damaged anything? I have disassembled the laptop a couple times to clean out the fan and replace the keyboard, with no problems.

many thanks

system:
Compaq Presario 2100 AMD
XP
40Gb, 756 Mb RAM
3 or 4 years old

I had the same problem with my ASUS F3E. Solved it myself. I have recognized that the ribbon cable (AWM E118077 2896 80C VW-1) connecting Synaptics Touchpad and main board has been bent by myself when reassemble. It had caused three of the connectors disconnected ( i tested both ends with multi- tester.)

It is very difficult to find a spare cable (the same one) here in singapore.

So I got the duty myself to repair the cable.

Fortunately i had bent near the closer end to the main board. I removed the disconnected (about 1.5cm) part with a paper cutter. Rubbed 0.5 cm of the cut-end to bring up the copper-lead connectors (This has to be done extremely carefully - I also passed this second time).

There was an existing plastic pallette in the removed end. I glued the same under the newly rubbed end - so that the thickness of the end gets the same as original.

Fixed the connectors back making sure I do not bend it again badly.

Hurrrrrrrrrrrrrraaaaaaaaaaaaaaaih!. It works guys. :)

But you have to have really good vision and confidence when doing the rubbing part. Because it can also remove the required metal lines in the ribbon. Make sure you have a very sharp paper cutter knife first.

Give it a try or else contact me if you need help. I'm in Singapore.

Member Avatar for stan91

I fed up with my broken ribbon. Couldn't make it to work.
Got new one from www.2fix.net for less then $10
Working fine now.

Edited by stan91 because: n/a
Member Avatar for PRAKASHOM9095

I also have similar problem after fixing the graphic nvidia chip by Repairer. no light comes for touchpad and machine is working fine with external mouse.
-thx

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.