A31p Annoying "Whine" and sporatic charging issues

[QcMarque]

So, I purchased an A31p off eBay that was listed as "...will stop charging around 30%... was told it was a capacitor..." The unit works great (latest bios, 2GB ram, 320GB hdd, etc) aside from the charging issue.

What happens is this:
I plug in power supply, screen brightens (based on power scheme) and battery begins to charge. When it gets to around 28-33% the screen dims (as though the power supply was unplugged) and there's a whine that comes from near the power plug - almost sounds like an ungreased fan. I've checked the fan (stopped it, etc) and it's definitely not that. My brother in law said it definitely sounds like a cap going out (I've never "heard" a bad cap other than when one literally exploded.)

Any ideas?


Also, 2 other items:
1) The ram clips are on the weak side (1 is actually broken off)... anyone know if I could acquire a couple new brackets to replace the originals (I have an IRDa station... do reballing and the like, so removing the old ones and installing the new shouldn't be hard)?

2) Lastly, I have a red hue to my screen when cold booting or if the lid is closed for an extended period of time. Could this be the LCD itself or perhaps the ATI video chip? I've thought about just reflowing/reballing the thing (possibly upgrading the CPU at the same time), but don't want to go through all the work if that's not the issue.

Thanks!

[goofyGAguy]

When it gets to around 28-33% the screen dims (as though the power supply was unplugged) and there's a whine that comes from near the power plug

Any ideas?

LCD inverter

2) Lastly, I have a red hue to my screen when cold booting or if the lid is closed for an extended period of time.

LCD backlight failing.

[rkawakami]

If it's not the LCD inverter (press the Fn+F7 key combination to turn off the display), then the whining could also be coming from an inductor.

[QcMarque]

The next time it starts the whine I'll try that... would the lcd inverter cause the system to stop charging?

[rkawakami]

Only if were to consume so much current that the voltage drops in the system and thus affects the battery charging circuitry. A bad or loose inductor can also directly affect the battery charger. The T23 system has a habit of developing loose inductors which can either prevent the system from booting or work perfectly but not change the battery.

[QcMarque]

Thanks for all the info... I'll be checking things tonight and reporting back. I wasn't able to find anything, but that doesn't mean I didn't use the proper search terms or the right sub-forum - but doesn anyone know of a tut or something that covers checking and re-mounting/replacing inductors (if that turns out to be the most likely cause)?

[rkawakami]

Checking an inductor is as easy as testing a fuse. If you have an ohmmeter, it should measure very near 0 ohms. If it's more than say 5 or 10 ohms, I'd consider it bad. With the T23 inductor issues it's very easy to find a loose one; they will practically fall off the board if you pry one side up. The culprit is a combination of oxidation and brittle solder. "Black pad" developing on the metal contacts + lead-free solder + board flexing = bad connections. When you remove the inductor, take a good look at the metal contacts. If they are grey or black, scrape it off with a flat screwdriver until you see the copper (usually) exposed. Use some solder wick to remove the old solder from the pads on the motherboard. Apply a very small amount of solder to the contacts on the inductor before placing it back on the motherboard. Heat the contact along the side of the inductor and the solder will eventually melt and attach itself to the board. Of course if you use your IR reflow oven, then you probably have solder paste and a good temperature profile to work with. I've hand-resoldered at least two dozen inductors on T23 motherboards and as far as I know, the systems are still working.

[QcMarque]

Well, I checked my inductors and they all are good (as far as can be told from a multimeter... without seeing the coils can't tell if there's a short). I made sure the solder on them is good, and still I have a "singing" inductor. It's the "upper" one between the ultrabay ports. I'll see if I can locate one on mouser, mcm, or one of the other sites (unless someone wants to donate a known good part, lol!).

I'm currently bidding on a known good A31p and if all goes well I'll have it end of next week - then this will be a parts/spare machine.

Quick questions - anyone know the highest-rated processor this system will support? I've ordered an Intel 2200BG card already, my current system has a 2GHz but if there's a better processor I'll order one (p4's are getting so cheap now, lol.) Also, is there a newerTthinkPad with RS232 and LPT ports (maybe fingerprint reader)? I looked over thinkwiki and didn't find anything better than the a31p, but that's not to say there isn't one. )



Thank again everyone! You've all been very helpful!

[ajkula66]

The fastest CPU these machines will support is P4M 2.6 Ghz, SL6WZ. These babies still command a fairly high price, and run quite hot.

And A31p was the last ThinkPad to have the ports you're interested in without being docked.

Fingerprint reader was introduced on higher-end T42/p models that were stripped of all but the most basic ports, so you'll need a T42/43 with a dock if you really need all of this stuff. FPR can't be added (unless you're intent on using an external one) to any ThinkPads of A3x generation.

[RealBlackStuff]

T23 and T30 also have the RS232 and LPT1 ports.

[QcMarque]

Well, I've been unable to find a new inductor... could be I'm searching for the wrong inductance value or something. The inductor has these markings on it:
097
H363

It's about 1/4" square, SMD, 4 terminal (2 per side). If I understand my research, it should be 36000uH and 9.7 or maybe 0.97 ohms?