WL-500g Deluxe: powers on unreliably

[wtzm]

Hello all!
In addition to my WL-500g which works flawlessly since I bought it in August 2004, I have recently added a WL-500g Deluxe (V) to my collection - mainly for experimentation and out of curiosity.
As well as my WL-500g its power is (usually) switched off during the night. Now I have the following problem: When power is reapplied in the morning, the Deluxe fails to power up - the leds which show lan-connectivity light up correctly, but the PWR-Led stays dark. The router isn't accessible via the network and no bootloader messages appear on the serial port.
It starts to work correctly if I disconnect and reconnect power again. Returning this unit for warranty repair is not an option, as the seal is already broken.
What I have tried so far: Adding an additional 100µF capacitor parallel to C180 for better input voltage filtering and an 1µF capacitor parallel to C118 (for stablilising 3,3V) didn't really improve the condition...
Has anyone else experienced this problem?

[Oleg]

You're #3 already. Have you tried using wl500g power supply with deluxe?
The Power On Reset is built using MAX811 IC. Perhaps you've to check surroundings and check reference schematic from MAXIM.

[Oleg]

P.S. Let us know of your progress.

[wtzm]

I have already tried another 5V power supply I had handy, although this wasn't the WL-500g power supply.
Thanks for the hint Oleg, have already found the ic on the pcb (fortunately there was only one suspect ). If I find a solution, I'll post it here.

[grisa2006]

Hello!

Is there any progress on it?

I had the same problem (Asus WL500g Deluxe).
I 've just unpacked the router at home, plugged in AC, and router
just did not powered, lan1-4 ports blinked once.
After several try, I was able to power it, but when I remove the
power supply, and wait for several hours or so, it did not power again.
I took it back to the reseller, and got another one.
But that one also had this problem, so I took it back again,
they gave my money back, but noted that they thought it is a "speciality"
of this router I didn't think so...

Anyway, I would give it another try, if I can be certain that this was only
a specific problem with those two router (uhh, unlikely?)

So, is there any asus wl500g deluxe out there, which were powered flawlessly
at first time?

regards
Andras

[wtzm]

Nope, no progress on my part.
I delayed the reset by pulling the #MR pin of the MAX811S low for a certain amount of time after power-on (few seconds), because I guessed that the problem is maybe related to initial instability of the supply voltage; but this didn't change anything...
I have also populated C157 with a 0,1µF capacitor (don't know why I did this - the solder pads were there, so I just tried it...). No change.
The MAX811 datasheet mentions that #MR should be left open, if it isn't used, but I don't think the way that ASUS implemented this (weak pull-down R124 to GND + C136 to GND) is linked to this problem.
Furthermore #RESET should have a 100k pull-down, which is 10k (R127) in this case, but then again the datasheet mentions that this value really isn't critical.
BTW: I only have basic knowledge of electrical engineering, so I'm probably the wrong person for finding the cause of this fault.
I wonder if ASUS is actually aware of this, so I might just try mailing them, explaining the whole situation (+ telling them that I know I have already voided the warranty) and asking them if they know of any workaround , which does _not_ involve replacing the entire bcm5365p or anything like this ^^.

[wtzm]

Update:
It seems like I have been successful in finding a workaround that fixes this problem on my router: A ~1000µF capacitor between #MR and GND adds a delay of approximately 4 seconds and now the router already started correctly 5 days in a row; without this modification it used to fail at least every second day.
So to all the people out there, who are experiencing this problem: Open case, look for the connector labeled J5. Connect the capacitor to the pins #RESET and GND (negative pin of the capacitor connects to GND, of course) and report if this fixed the problem or not. I refrain from posting pictures here, because I had only 100µF caps in stock, so this looks like a terrible mess.
If you don't have enough room for the capacitor near J5, you can connect it directly to the MAX811S, pin 1 (GND, marked with a triangle) and pin 3 (#MR, it's the one nearest to the processor).

Bear in mind that you're doing this on your own, neither I, nor anyone else (including ASUS) can be held responsible if you follow this instructions and destroy you router, harm yourself, et cetera.

[Pjotrek]

One of my (three) WL500GX’s has a problem at power-up. If it has been without power for more than about 10 minutes, it comes up without PWR, AIR and WAN leds. The active LAN leds do come on. The router does not respond to pings from wan or lan.
If I now turn off power for a short time and then reconnect, it comes up normally, and everything works perfectly.

I have tried everything I can think of, clearing nvram with ‘mtd erase nvram’, reflashing bootloader, resetting to factory defaults, reflashing other firmware, both Oleg, OpenWrt and the special Clear-Flash-firmware, but nothing seems to help.

[Edited - after move]
I will now try what is described here above. A report will follow.

[Edited - after applying capacitor]
Nope, that did not help. The only difference is that now the WAN-led also comes on. PWR and AIR stay off until the unit is powered up again.

[Edited - after applying 2000 µF]
2000 µF made it! Now it works! Thanks everybody!