# My gigabit switch



## kamojamo (Dec 8, 2007)

Hey all,
I have a D-Link Gigabit Switch DGS-1008D
It's been absolutely great since i got it about a year ago. I've had my computer on for several days as I have been downloading some large files. I finished the downloads and left my computer idle for a few hours whilst at work. Then I came back home, i go on the internet, i load one site, begin loading the second and suddenly i've got no network connection. I go to where my switch is located (center of the house) and the LED's are flashing. As you know, each lan cable coming in to the switch is represented by and LED on the other side. 

The router flashes 
-all LED's on for 1 second
-the LED for my computer for 1 second
[repeat forever]

I've turned off the power, turned it back on and it does the same thing again.

I took it away, unscrewed it and had a look inside, it was relatively hot but there was no smell and there isn't any obvious physical damage (like blown capacitors or melting or anything).

What do I do? 
Can I reset this thing somehow? (thought turning it off and on would do it but no)
Is there some sort of troubleshooting thing I can do?

Thanks in advance, these forums are always really helpful!

kamojamo


----------



## Kreij (Dec 8, 2007)

Was there a power surge or anything odd?

Switches (including D-Links) are pretty reliable, but they do fail on occasion.

It could be that your poor little switch bit the dust.


----------



## kamojamo (Dec 8, 2007)

thanks Kreij,
there was a lot of rain last night and two or so lightning flashes but
-we didn't have a blackout or obvious surge
-there are other devices that would go before the switch (i think)
-the switch is plugged into a surge protecting 4way power cable thingy.

I've contacted D-Link support, but I'm not sure how long it'll take for them to get back to me!

kamojamo


----------



## Kreij (Dec 8, 2007)

Hi Kamo,

You can have a lightening flash that cooks sensitive elctronic equipment but does show itself visibly (ie. lights dim or flicker).

Surge protectors are great, but a really fast surge will slip past the clamp time resulting in toasted hardware.

I am not presuming that this is your problem, and your contacting the manufacturer is the correct first step.


----------



## kamojamo (Dec 8, 2007)

ok thanks

but say it wasn't the lightning (i really don't think it was)

what else?
is there anything I can do?

wouldn't "Cook" imply that it wouldn't even turn on?!

thanks

kamojamo


----------



## oily_17 (Dec 8, 2007)

On mine,although it is a Linksys, a flashing green LED means that the port is transmitting data.

Does the switch not run a diagnostic when you turn it on.

EDIT: OK this is from the manual for your switch.



> LED Indicators
> The LED indicators of the Switch include Power, 100/1000Mbps, and Link/Act. The following shows the LED indicators
> for the Switch along with an explanation of each indicator.
> 
> ...


----------



## kamojamo (Dec 8, 2007)

thanks, that's helpful
but unfortunately, the light blinking isn't like that, and it goes on forever.
Mine has 8 ports. It blinks all of the LEDs on the bottom row, then blinks mine (just number 8), then all on the bottom row, then mine (just number 8)

like it might be saying "error - on number 8" "error - on number 8" "error - on number 8" etc.

so yeah.

I rly don't want to have to pay AU$100 for another one!!

thanks so far
any more suggestions?

kamojamo


----------



## ddcruz (Jan 24, 2009)

*Solution*

Hello all

kamojamo, I know this response might come to you a bit late, but none the less it might help others who have this issue. I had exactly the same problem until recently, and looks like I found the solution (at least for me).  So I thought I'd share it here, since I have not seen a real solution on the various forums I've visited through.

The one common thing I've noted when searching on this and other forums re the 8 bottom blinking lights and then the top right blinking light, repeating over and over again was about a power surge / storm etc.

The exact thing happened to me.  A couple of months ago there was a really bad storm in S.E. Melbourne, we had a black out in our area and there were some spikes in our electrical systems. 

When the black out was over my Gigabit switch was doing the same routine re the lights.  The problem for me was the actual power supply unit.  

This Switch I've had is about 1.5 yrs old, dunno if I can claim it on warranty from dlink.  I've checked the dlink au website and it quotes 5 years, but dunno if it covers storm damage.

Anyways, I took the faulty power supply and the switch to my local jaycar store today.  The sales guy noted that the output should be 7.5v, however when he did a test, it was actually showing 12v.  He said that the switch must have some sort of built in protection, cause usually supplying 12v to a device that needs 7.5v should have fried the device.

We tried out a replacement power supply and bang.... back in business.

The only kicker was that the replacement power supply cost me around $39.95, cause it's one of those fancy multi volt ones.  If you can find one that is fixed at 7.5v it might be a cheaper option, and if anyone can find one, please respond to this thread, and link it here.

Please let me know if this has solved your problem.

Cheers
deXta


----------



## Tau (Jan 24, 2009)

are you sure its an issue with your switch?

Try bypassing the switch and router and plugging directly into your modem see if the issue persists.  if it works fine plug in the router and repeat the test.  if all goes well plug the switch in, if it stops when the switch is added then you will know that the switch is the issue


----------



## ddcruz (Jan 24, 2009)

*It's the switch*

Hello Tao, thanks for your response, but yes it was the switch all along.  Changing the faulty power supply for the switch fixed the issue for me.


----------



## Wobbly (Jan 28, 2009)

After today's scorcher (36C inside my house when I got home from work!) my DGS1008D died as well - just the lower LEDs flashing forever.  The router was roasting hot, as it was stacked below my ADSL modem as well which just compounded the problem.  I figured it died from the excessive heat, but after testing the output from the power pack it looks like that's the culprit as well - 12v according to my multimeter.

Anyone tried getting the power pack replaced by dlink in AU?


----------



## ddcruz (Jan 28, 2009)

*Dlink Warranty*

heya Wobbly

I've checked on the D-Link website, the warranty for Unmanaged Switches is 5 years.

http://dlink.com.au/tech/warranty.asp

I called up tech support and they sent me an RMA via email.  I only spoke to the receptionist though, so I don't know if I should send in the entire unit with the power supply or just the power supply.

However power supply I bought from jaycar does the job well.


----------



## freetvuser (Nov 2, 2009)

ddcruz said:


> When the black out was over my Gigabit switch was doing the same routine re the lights.  The problem for me was the actual power supply unit.



Thank you very much for identifying the problem. My switch have exhibited exactly the same problem. I have decided to figure out what the problem is with power supply. Had to cut the cover it is glued as not to be opened. Inside I found defective electrolytic capacitor (1000mF 16V). Replaced it. Now switch works just fine.


----------



## hat (Nov 2, 2009)

I put all my important stuff on surge protectors. I have one power strip that takes care of my penrium 3 computer, my laptop, my PS2 and my printer... I need to have it replaced with an actual surge protector. Plus, if you buy a surge protector they usually have some sort of warranty that if your stuff gets toasted while on the surge protector, they give you money to cover the damage.


----------



## freetvuser (Nov 5, 2009)

This issue has nothing to do with surge protectors. It was a defective capacitor. I have seen allot of those in failed motherboards. There where allot of discussions around different forums about failed capacitors in motherboards. If you look at those failed capacitors you will see that top of the capacitor is bulging out that is a clear give away that it is gone. I hope this will help some one else.


----------



## robert_s (Dec 19, 2009)

Just wanted to say thanks to @ddcruz and @freetvuser! I ran into exactly the same problem today - all of the sudden my DGS-1008D Rev. C4, which had been operating flawlessly 24/7/365 for three years, stopped working and blinked the LEDs in exactly the same way as you described here. I searched for "d-link dgs1008d led error codes" and that led me right to this thread.

I followed @freetvuser's suggestion and replaced the bad capacitor in the power supply and now my DGS-1008D is up and running again!

Some additions:

1. To open the power supply, you can use a thin saw to saw in the crack on one of the long sides. Once you're through, put a big screwdriver in the sawed crack and twist it to crack the other three sides open. This method allowed me to keep the casing mostly intact and tape it together after replacing the capacitor.

2. After replacing the capacitor, I measured the output voltage again, and found it was still close to 12 volts (nominal output is 7.5V 1A DC) - yet now the switch is happily initializing and working...

3. The power supply is as simple as it gets: Transformer, 4 diodes, capacitor. You can't build a DC power supply cheaper than that. The upside is that the parts are so standard that you can easily replace them.

Again, thanks for this thread, guys - it helped me fix a broken switch today!


----------



## lemonadesoda (Dec 19, 2009)

^ I would be careful with that. If it is supposed to be 7.5V but you are reading 12v then something else might be problematic. Test the ranormer, test the diode bridge, can you scope and check the output is "clean"? 12v might not be 12v dc but some ac component in it like 6v-18v... a scope could help you there.


----------



## robert_s (Dec 21, 2009)

lemonadesoda said:


> ^ I would be careful with that. If it is supposed to be 7.5V but you are reading 12v then something else might be problematic. Test the ranormer, test the diode bridge, can you scope and check the output is "clean"? 12v might not be 12v dc but some ac component in it like 6v-18v... a scope could help you there.


Good suggestion. I dusted off my old scope and had a look at it - and it's a nice flat DC voltage, only at 13v instead of the 7.5v it should be according to the label.

So I took the power adapter from a DGS-1005D Rev. C3 I have here as well (which has been operating flawlessly) and it appears to be exactly the same model. The sticker on it also reads 7.5v, 1A - and the scope also shows a nice flat 13v DC coming from it.

Then I took the power adapter from an older DGS-1008D Rev. B3 (still working flawlessly as well), and it's a different model, labeled as 5v, 3A - and the scope shows a flat 5v DC coming from it.

So I conclude that the DGS-100xD Rev. Cx power adapters (at least the European 230V/50Hz models) have always delivered almost twice the DC voltage it says on the sticker label. And since these aren't switching power supplies, I suppose it makes no difference whether you put a load on it or not (or am I wrong!?). Nonetheless, the switches don't seem to mind the higher voltage, just as long as it's DC (i.e. the capacitor is ok)...


----------



## fwlehmann (Dec 31, 2009)

*Don't forget the lo load voltages*

With a bit of electronic background you should remember the relationship between V / A / R

High Voltage with low amp rating can suply a high current (Amp) device at a lower voltage. 

ie, measure the power supply with no load and 12-14V is indeed normal. (for a non switched power supply using pasive components only - ie cheap)

the moment you load it with say 1A the voltage drop to 8.1 (Tested on a brand new Unit just taken out the box.) remove the load (ie less amps = higer voltage) and you back to +-13V

You can use ohms law as well to calculate the Resistor needed to give you the desired voltage, and you can then measure the A. 

It is no fault of Dlink to have the PSU's as it is. if you load it with 1A it provides the right voltage. 

It is however wrong to use such a cheap electrolytic capacitor, where the electrolyte is basicaly dry even in a new psu. The Cap measured outside the rated value by 55% ! This in the long run will cause problems described, after about 6-12 months if not sooner. also because the tolerance is so out, the 16V is very close to the actual output and it needs a VERY light surge, that won't be noticed even on a normal multi meter to break it. 

My advice is replace the Cap now, even if yours is still working. (You would lose the warantee on the PSU though) but i'd rather have no warantee, and a working switch than one failing on me in a critical network environment. 

But the best solution is a Switchmode PSU that delivers 7.5 no matter the load. (Like Cisco etc use) Then your switch should last years and years to come. 

Wilhelm

ps happy new year to all.


----------



## fwlehmann (Dec 31, 2009)

*voltages agan*

5V, 9V, 12V etc is easy to generate stable with the 780X range of regulators. 
7.5V is a bit more tricky. There you can look at an LM350 adjustable regulator that can eaily cope with the 1A needed. Plenty of Kits on the market for beginers as well. You can easily make your own 7.5V supply for under $10. (and it should be better quality than the factory one)

Wilhelm


----------



## tricity (Jan 18, 2010)

fwlehmann, I think you are on the right track. I had the same problem, lower row of LED blinks, single upper LED blinks. It appears that this error signal has something to do with the power supply.

A few observations about the D-Link's power. Internally, the switch does not use the 7.5V. Rather, there are two switching step-down converters to produce 3.3V and 1.2V, respectively. These power the cable drivers and the chip.

Because of these internal converters, the external voltage is relatively uncritical (as long as it it clean). The converters fail at voltages below 5.5V. I tried them up to 10V, and they work reliably. At 7.5V, the switch draws 500mA. At lower voltages, the current is higher, and it goes down to some 380mA at 9V. This indicates that these converters become less efficient at higher voltages.

My original D-Link power supply provides 12V no-load voltage, but this drops to 8.5V when it is connected to the switch. This is typical behavior for an unregulated power supply. If you want to replace the power supply, you don't need to have an accurately regulated one (although a regulator, such as the 7808 or the LM350 suggested by fwlehmann help get clean power). With clean power, I mean power that has low ripples, fluctuations, and transients. If you have an oscilloscope, look at the input (those 8.3V or whatever it is in your case). If your D-Link switch does the error-blinking loop, chances are good that your power input drops below 6V at some time in the 60 Hz cycle.

I have not found confirmation in any other post, but I could imagine that this error code indicates unacceptable power fluctuations.

Quick fix, also mentioned elsewhere in this post - add a capacitor. Example, solder a 4700 microfarad, 25V capacitor across the power input (voids warranty, needless to say). My guess is that this will help in many cases where the cheap wall plug-in power supply is not totally blown.


----------



## tricity (Jan 18, 2010)

I thought perhaps some photos would help. There is a lot of space where to place a capacitor. I decided to use that cut-out region. On the lower side of the PCB, there is the 7.5V input plane (see my fiber-tip markings). Above, on the other side, is ground. You need to scrape off a small region of the green soldermask to expose the copper. Then solder the capacitor wires to the exposed spots.

If you are at it, you might as well add a MOV or a transient suppressor the same way. This might help you in a lightning storm (unless the transients are carried by the network cable - the D-Link switch has no protection from that end!).

And, yes, I think the chip gets a bit hot, so I added a heatsink as well (orange thing in the second photo).


----------



## robert_s (Jan 27, 2010)

@tricity, could you add which hardware revision of the DGS-1008D you have? The sticker on the bottom of the case should say which one. As D-Link has been selling different hardware designs under the same model name, adding the Hardware Rev. to the photos you posted is important.


----------



## tricity (Jan 27, 2010)

Good point, Robert, and thanks. 

The switch has the part number BGS1008DA.C1, thus the hardware version is C1.


----------

