BIOS battery examined

Now that even the bios battery I purchased directly from Dell in 2007 is starting to fail (spontaeous clock and bios reset et.c.) I thought I’d examine the bios battery to see if you could switch to a cheaper/better solution than another Dell battery.

As you can see from the first image the battery specs are: 7.2V, 20mAh, Ni-MH, 6/V20HR.

In the second image you see some nasty battery leakage and now we know that there are 6 x Varta V20HR (1.2V/20mAh each) in there, “paddles” for the cable and a metal strips in between for connection, on top and in between (barely visible in between the batteries in the picture). Furthermore the paddles and the metal strips are “punched” into the batteries (there’s probably some fancy technical term for that).

A bit of googling turned up a lot of results, the battery in question is common and cheap, the only problem being the remounting and punching/securing of electrical current to all the batteries.

I’ll leave y’all with this information for now as I personally don’t really crave a correct time and date on the l400… if you decide to make your own battery pack (and succeed) don’t forget to leave a comment!

Side note: Replacing fans on a Dell Dimension 8100

Please excuse my polluting this L400 blog with a post about the Dell workstation “Dimension 8100″, however it could be interresting for a few people and I’m not about to start a whole new blog for one post…

Anyway, I’ve just completed a replacement of both the system/chassis fan and the psu fan on this machine and it is quite possible although a bit cumbersome. Chassis fan (sucks out warm air from the cpu heatsink/shroud) is quite easily replaced, the only “problem” is you have to keep the motherboard plug since it’s a proprietary Dell connection. Just cut off the cables from the new fan and splice them onto a stump of the old fans wires+connector and you’re done.

I’ve put in 2x Zalman fans, one 92mm chassis fan (ZM-FM2) and one 80mm PSU fan (ZM-FM1). Shouldn’t set you back more than 12$ for both.

The ZM-FM2 runs at 2825rpm when installed as is = untolerably high noise, think hairdryer. You really need to use the resistor that comes with the fan. In the pic you’ll se I made a new incision for the resistor but now that you know you’ll need it you can just include it when you make the first cut. Trial and error my friends… With resistor the fan runs at ca. 1700rpm with greatly reduced noise. No errors reported.

PSU fan does not give any speed reading (I don’t think it did before switching either) but should run at maximum to keep the psu happy, the ZM-FM1 is rated at 0.17A, 3000 rpm while the original fan is 0.41A, 3600rpm (this manufacturers documentation says 0.26A though). There’s still noise coming from the psu that I had hoped to get rid of, a sort of electrical whine / buzz. Well, atleast the overall noise is reduced and the computer seems happy enough. No errors reported.

PSU side views (Cover removed)

Old PSU fan (right) and new PSU fan (left)

New chassis fan after the cable mod

40mm fan working in the L400!

Fan mod complete, a fine-toothed saw and a nail file gave two sides the shaving they needed to fit. I ended up having to do some light filing on the palmrest assembly too; a 1mm trim on a 1cm area above the fan. It’s where the topmost leaf of the fan is resting in the pic below. Not a side-blowing fan you might remark – true, but it’s better than no fan at all, the stock fan makes such horrible noise. And hey, even if it sucks it blows…

Fits? A snug fit, not secured but ok. Thanks to the small spaces it’s more or less forced to sit where it is and shouldn’t be able to move around too much. Added a patch of double sided tape underneath, not sure how much contact there actually is between it and the case/felt-pad originally installed. A slight bulge in the upper left corner of the keyboard could not be avoided. Edit: The fan measures 40x40x10 (original size)

Noise? Well, the fanleaves themselves make no discernable noise, there is some kind of little *krrx* coming from what may be miniscule dust (from the filing) stuck in the motor. If I had to do it over again I would enlist someones help and have them vacuum the filings away from the fan as the operation was performed. If the keyboard is screwed down all the way with the leftmost screw the fan starts hitting something. Leaving it slightly unscrewed shouldn’t be an issue.

Fan control? Sketchy as it ever was. Starts when the machine boots and then shuts down, like before. Stressed the 500MHz setting for 30 minutes but could not get fan to start, like before. Restarted and set it att 700MHz = fan runs constantly, as it did before if the system was hot when rebooted. With the new fan that’s not an issue! Testing will continue…

All in all a more or less sucessful mod I’m proud to say

Oh, and a useful tip to anyone about to adapt two wires into a three-pin connector: Leave a portion of the old cables sitting in the connector! I cut it off right by the white connector and that just makes it irritatingly difficult to stuff new cables in there and securing them with tape. Duh! Just leave some and intwine the red and black cables from old and new and put a little electrically insulating tape around it and it will look neat and professional. If my fan solution works in the long run I’ll sacrifice the second dell fan to get a decent looking connection.

Cooling examined 2

Tried a 5mm heatsink with thermal tape on the cpu and it is definetly 2 if not 3mm:s too thick.
Adding two bottom assembly screws in the previous heatsink holes could perhaps draw the motherboard
1 mm downwards on the cpu side, but you’re left with a wonky board and no way to draw
the needed nb-sink down an equal amount. Darn again.

As it turns out the fan included in the Revoltec chipset cooling set should be much easier and more effective to use than the Scythe Kaze mini, this due to the open sides of the revoltec fan. The Kaze mini has closed walls all around the fan making the modding needed far more extensive than getting rid of a few mm:s of single plastic ridge on the revoltec fan. Good job revoltec. Link to their product description is avaible in links in the right column.

Fan did start with the wires merely held on the connector, so the fan mod should work out. The thing is completely silent when out of the case anyway, I’m hopeful about getting it in there. Did not run constantly as I thought it would (it doesn’t have the third, yellow cable = rpm readings), it ran when turned on and then stopped like the normal fan. Will have to mod the plastic rig of the fan though, a bit too big and round. Doublesided tape will be what’s keeping it there, none of the holes match.

Cooling examined

Hesitance be gone! Cooling on the L400 demystified: CPU cooled via glue/paste contact (dried up in these shots) with metal tape via heatsink (helped by fan when installed). NB cooled via glued/taped on metal plate which scarcely has any contact with the steel wing.

The cpu seems to be covered in some kind of old glueish looking gunk. Would it possible or recommendable to clean it? If I put a heatsink on it I will have to throw away the whole stock cooling rig. Would a small heatsink get too hot and perhaps melt the keyboard close above? Could a slightly bigger heatsink sit comfortably on this small processor? (Jiggle risk…)

On the other hand, the current heatsink is pretty nifty, If I could find a good pad of some sort I could
just remove the gunk, remove the metal tape-thing attached to the heatsink (the grey patch) and reattach
the stock cooling. That is minus the cutout I will have to do to fit the heatsinks on the nb. Currently
the nb cooling pad/metal piece barely touches the metal wing so I’m not worried about temps there.

Ran system for 4 hours after reassembly, the fiddling with the heatsink caused no obvious problems.

Update: There’s not really any choice as far as the cpu and nb goes, you have to use the stock stuff. The lowest heatsink I’ve found is 5mm thick which would produce a noticable bulge in the keyboard. 4mm would work but at this minimal height any obscure heatsink would have such low heat dissipating abilities that it wouldn’t really do any difference for the cpu. (Stock is approx. 3mm thick)

Some rough measurements in mm (w – l – h.  Argh, no table function in the wp editor…)

CPU die 9 – 10,5 -
NB die 29 – 29 -
NB pad 25 – 25 – 1
GPU die 22,5 – 22,5 -

I’ve decided to keep the stock cooling solution but replace the old tape-paste stuff with atleast new, albeit cheap thermal tape.

Ordered:
1 Revoltec chipset cooling set (only bought it for the loose pieces of heat transfer-tape included) 85SEK/14$
1 Scythe Mini Kaze 40x40x10mm fan 80SEK/13$ – RETURNED (revoltec fan better for my use)
1 Dual CF to IDE adapter from www.webconnexxion.com (Addonics distributor in the EU) 19€, 36€ delivered

A few thoughts

CPU-cooling examined: The top part is removable by getting the three scews from under the motherboard.
What lies beneath is hard to say. There are two little cables coming out from what I guess has to be the cpu
and nb. Perhaps one could try removing them and see what happens? Dunno.

I’m hesitant about removing the current cooling arrangement. It could prove difficult to reassemble or replace.

Pre mod weight: ca 1362g (no main battery)
Post mod weight: ca 1337g (I kid you not.)

Difference ca. 25g. Not very much, but atleast I’ve gotten rid of some unnecessary stuff and improved circulation. Replacing the hdd with a cf-ide adapter and 1-2cf cards should nudge the weight in the right direction, lose some EMI, and further improve overall system temperature.

Ran for 4½ hours: HD finished at 43C, could be due to actual use for a while.
Ran for 2 more hours: Samsungs hd diagnostic tool. The hdd is making intermittent screeching noises. No fault found.

Round up:

* Remove fan – DONE. Seems to work ok.
* Remove modem – DONE. No problems.
* Remove speaker – DONE. No problems.
* Remove parallell and modem port if possible – FAIL. Not possible.
* Remove battery latch (battery is dead) – DONE. No problems.
* Replace or refurbish cpu/nb cooling solution
* Alleviate the EMI on line-out
* Replace failing HDD with CF-to-IDE adapter and 1-2 CF cards.

Cooling modification to be examnied further next. See y’all.

Oh, by the way, does anyone know of a cheap and fairly reliable way to measure temps, f.e. wireless IR-thermometer or some kind of small sensor thingy? (Cheap = less than 50$ shipped)

If so, leave a comment please.

Removing battery latch (+ motherboard reference pic)

Since my battery is dead and a new one costs ~700SEK (~115$) I might aswell remove even the possibility of putting a battery in. Thus: battery latch removed. You do need to remove the motherboard since the metal arm extends under it, holding it where it should be. Very easy operation, just follow the manual.

Result? Some more gaping holes but what the heck.

Overview: The underside of the motherboard. Notice where the cooling solution can be loosened (part of it), it’s the triangular thingy there to the left. You can also see part of the heatsink (white, curved for fan airflow.)

Removing the speaker

I first thought I’d try running the system after every little mod but once you’re in there you might aswell continue…

The speaker is located at the bottom left, just under the end of the grey, vertical tape you can see in the overview pic. There is a grill in the bottom casing to let the sound out that I had forgotten.

Overview: Audio EMI shield removed and placed to the left, speaker still mounted.
(Don’t ask me what that curved stain is, I have no idea. Don’t use a wet paper towel though, just brush any oddities off.)

After removal: Line out still works ofcourse (mic not tested). EMI seems worse than before though, but much of it seems to be from the HDD, which should improve when switching to CF. Could you insulate the port from EMI by simply adding some light but shielding material? If you know of any such stuff leave a comment…

Removing the modem

After another failed attempt at removing the display assembly (needed to remove modem) I realized the manual must have an error. You have to remove the screw securing the lcd flex cable hold-down clip before removing all the other display stuff. Do this as soon as you’ve removed the keyboard. Be careful when you open the display again, the hinges might skew backwards, damaging the case (…)

Overview: Removed fan, display assembly, palmrest assembly.

The actual removal of the modem is a piece of cake, just nudge it straight upwards, there’s a small connector to the right under the board. Then remove the little cable going towards the modem port. Done!

Note: When you remove the modem retainer bracket you also remove the two middle holes for securing the keyboard. Not a problem in my opinion, the keyboard still feels stable, empty holes covered by bezel.

View: Modem and retainer bracket removed completely.

Removing the fan

Nothing complicated about the removal itself, the question is: will the system work without the fan? If so with warnings? Is it stable? (Click image to enlarge)

Disconnected cpu fan. No warnings in bios, no shut downs. Ran it for 4 hours with OO and FF + Speedfan.
Speedfan reports two temps, but one is constant at 50C and thus probably isn’t cpu core or any meaningful sensor. The other one is the samsung hdd which started at 25 and levelled off at 40C.
(HDD model: Samsung Spinpoint M60 80GB (HM080IC). The disk in the pic is the stock hdd from way back, had to find an untouched view of the system.)

Removed backup battery and removed fan completely. No warnings in bios, takes longer to boot due to memory test though. Ran for 4 hours as above. Edited bios settings seem to keep? But I guess they would disappear had I unplugged it from mains. Will keep the backup battery due to windows warnings and hickups. It’s 1987 again, yay?

Tried opening up the machine further and thought things were going well, until *crack*… there went the
right display hinge. Apparently I didn’t follow the instructions, but hey, I blame the poor lighting.
Be careful though, the plastic breaks fairly easily and it’s such an unnecessary thing to do.
Update: it wasn’t the hinge itself, it just snapped loose, it was the back of the case that cracked by the lan port. Darn. Not very visible though.

Fan details: Left fan is the original that came with the computer. Right is the replacement I bought via Dell about a year ago I think. Both old and new are absolutely unusable if you want to keep your sanity. In underclocked mode (CPU at 500MHz) the L400 rarely uses the fan so then you can live with it.