Is there a connector for addition of a HDD activity light on Aspire TC-780(KBL) Motherboard

YrbkMgr

 I guess I'm old school, been computing since the 80's. I'd really like an activity indicator light on the outside of the case. Is there a connector on my TC-780 KBL motherboard to which I can connect a light? I have HDD Activity cable/wire with a two pin connector from older machines I have. I'd like to see if there's a connector for this function on the MB.

I appreciate any and all replies.

Thanks...

billsey

I was thinking it best for you to know which pair is the switch first, because plugging the switch in to a live circuit would be a bad thing. The logic for that was actually flawed since plugging the switch into an LED port is only bad if you also have a switch plugged into the switch port. I'll try and be more detailed... Since in order to test the system for a HDD light you need the system to be turned on, you have to have the power switch connected in order to turn the system on and the wiring connection covers up all pins. If you knew for sure which pins were the switch then you could put a switch on those pins and turn the system on without having the full connector connected. Once you can turn the system on and off without the full connector in place, you can easily test every other air of pins to see if any track HDD activity.

Now to your questions...

I don't believe there would be any harm by connecting the LED to those pins in order to test. The LED only allows electricity to flow if it's connected to a ground on one side and power on the other, if it's plugged in backwards no power flows, so either way you don't short out the MB. The issue is it's a bit of a pain to install the sockets into that connector and you don't want to do that any more often than needed.

Paperclip extensions might work, but the bottom portion really want to be female in order to get a good connection to the pin on the motherboard. It might actually be possible if the wire was only touching a portion of the time to get arcing as it shifts around. Arcing would be a bad thing. If you have a set of Molex crimpers and some female connectors you could do it safely though. You just have to still deal with removing them from the connector after testing is complete.

Lastly, I never try and outguess Acer's people. I'm sure they have good reasons (or at least potentially good) for restricting access to service guides. We just have to live with it and at least they do let us Acer Aces access them and share snippets...

billsey

If there is that signal on the MB, it will be in header #8 on this diagram. There are more connections than are needed for the power button and power LED, so you have a chance.

YrbkMgr

Thanks so much for the speedy reply. I verified that A) the connector looks like what you posted, and B ) that there are more pins on that connector than are being used. So grateful. That said, can you make a recommendation on how I can determine which pins would be for the HDD Activity signal? The print is so small on the board that I can't make anything out definitively, and I'm not even sure if it would be silk screened onto the board; so if there's a pin-out or something that can "get me there", it would be most helpful.

Finally, the picture below is the type of wire that I have - I have a half dozen of these types with small variations in the connector, but they're all two-wire pins. Any suggestions on a next step to see if this project will work out?

billsey

So the wiring on those is usually setup with adjacent pins across the connector or adjacent pins along the connector. So:

oooooxoo
oooooxoo

or

ooooxxoo
oooooooo

The LED is polarized, so if you plug it in backwards nothing happens, if you plug it in forward the light lights when appropriate. As long as you are jumpering between two pins using the LED you are likely safe to just try them out. How are the power LED and power switch connected now? Across or along?

YrbkMgr

billsey said:

So the wiring on those is usually setup with adjacent pins across the connector or adjacent pins along the connector. So:

oooooxoo
oooooxoo

or

ooooxxoo
oooooooo

The LED is polarized, so if you plug it in backwards nothing happens, if you plug it in forward the light lights when appropriate. As long as you are jumpering between two pins using the LED you are likely safe to just try them out. How are the power LED and power switch connected now? Across or along?

If I understand how to read your diagram right, it looks like it's adjacent - your second example. I've included a picture for verification. Given that, which two pins do I try? Also what's the best way to test it to make sure the polarity is correct? Can I insert some kind of "extension" (like a pin or something) in the top of the existing connector so I can test?

Again, many thanks for your help with this. After a year, I feel like I'm making progress...

billsey

OK, the next step is where it starts getting tricky. You know those four wires pair up to be the power switch and the power LED. That is four positions on what looks like a fourteen pin header (7 to a side). If I were to make a guess I'd say the next pair in the same row would be a possibility as would the first, second or third pair on the other side of the connector. The last pair sits crosswise and I'd guess is less likely to be significant. If you have more wire pairs setup like your LED example, you could take one and put a switch on it. Plug it in where you currently have the green with white dot and white with green dot. Flip the switch and see if your system turns on. If it does that's the switch pair, if it doesn't that's the LED pair. Once you know which is the LED pair and have the ability to throw the switch, take your LED and put it on the power LED pair with red to color/white and white to white/color. Turn the machine on and see if it lights. If it does our polarity is right and you can try moving the LED to each other possible place to see if any show light on disk activity. Remember that disk activity is more likely to be a flicker than a steady light. If you are able to pinpoint one pair as disk activity then you use a tiny probe to flex the little metal piece that holds the sockets into that Molex connector on the end of your LED and then put those sockets into the main 14 pin connector.

Let us know how it comes out. Just make sure you don't accidentally put the switch onto an LED output when the computer is powered up, that could cause a sizzle, and the best result would be melted wires... You are safe putting the switch on an LED if there's nothing on the power switch LED, since it won't turn on.

As a hint, I think this is the equivalent header for a G3-710, so the pins might be a close match:

YrbkMgr

Thanks for a great reply! So here's the thing - in your answer you lost me with "Once you know which is the LED pair and have the ability to throw the switch, take your LED and put it on the power LED pair with red to color/white and white to white/color." I'm unclear what those instructions mean, and moreover, what the goal is. So after giving that considerable thought, I'd appreciate your opinion on this strategy...

Almost every diagram of the pinouts of a front panel connector on a MB, almost regardless of mfr seem to indicate the same pinouts for HDD Activity LED as the image you posted for the G3-710. Is there any harm in me hedging my bets by trying pins 1&3 from that diagram? Will anything bad happen if I'm wrong? It's a "guess and check" method, so I'd just like to confirm that I'm not going to fry anything.

Another thought is, couldn't I use paperclip extensions on those pins and plug the HDD Activity LED that I have into those and confirm both polarity and functionality? In lieu of that, is there a signal I can probe for with a multimeter to confirm that it's HDD activity?

I sure would appreciate your thoughts.

Finally, most MB mfr's produce some sort of technical manual with pinouts and such - why is Acer such a non-conformist in this regard?

billsey

I was thinking it best for you to know which pair is the switch first, because plugging the switch in to a live circuit would be a bad thing. The logic for that was actually flawed since plugging the switch into an LED port is only bad if you also have a switch plugged into the switch port. I'll try and be more detailed... Since in order to test the system for a HDD light you need the system to be turned on, you have to have the power switch connected in order to turn the system on and the wiring connection covers up all pins. If you knew for sure which pins were the switch then you could put a switch on those pins and turn the system on without having the full connector connected. Once you can turn the system on and off without the full connector in place, you can easily test every other air of pins to see if any track HDD activity.

Now to your questions...

I don't believe there would be any harm by connecting the LED to those pins in order to test. The LED only allows electricity to flow if it's connected to a ground on one side and power on the other, if it's plugged in backwards no power flows, so either way you don't short out the MB. The issue is it's a bit of a pain to install the sockets into that connector and you don't want to do that any more often than needed.

Paperclip extensions might work, but the bottom portion really want to be female in order to get a good connection to the pin on the motherboard. It might actually be possible if the wire was only touching a portion of the time to get arcing as it shifts around. Arcing would be a bad thing. If you have a set of Molex crimpers and some female connectors you could do it safely though. You just have to still deal with removing them from the connector after testing is complete.

Lastly, I never try and outguess Acer's people. I'm sure they have good reasons (or at least potentially good) for restricting access to service guides. We just have to live with it and at least they do let us Acer Aces access them and share snippets...

YrbkMgr

billsey, you ARE an ACE trailblazer!! Most wouldn't give me the time of day as it relates to thinking about this project. You, sir (firm salute), have shined where others have dimmed. (Insert additional gratuitous thanks and admiration of your choice here).

My procedure would be to only connect anything to anything with the power off, then turn the power on - I'd be able to tell in short order if the pins I've chosen were right or not or in the right orientation. If there were a possibility to do harm from testing, I'd just buy some Male to Male jst-style extensions and try it that way (see image below). Since it appears that there won't be harm in (basically) jumper-ing the suspect connectors (one pair of those pins are likely for a reset switch, so... there's that), I'll just hedge my bet and go for pins 1 & 3. If it doesn't work, I'll cut bait and live with no HDD Activity LED. I have a software utility that shows it in the system tray, but I'd prefer a real light.

All of that notwithstanding, again, my most humble thanks for your time, energy, as well as your considerate and articulate replies in helping me sort this. I hope that something good goes your way.

Here are the extensions I was referring to:

billsey

Yeah, I've used that type of extension a lot over the years, most recently mucking around trying to get PID speed control on my CNC router.

The key sentence in your latest message is:

My procedure would be to only connect anything to anything with the power off, then turn the power on

In order to turn the power on to a computer power supply, you short the power button pins together on that connector. It's a chicken and egg thing unless you already know which two pins are the switch... Be sure and let us know how things work out.

Hashym

Hey.. YrbkMgr...i really want to know if hdd activity light worked out on acer aspire tc 780... If it worked what are the correct pins for the hdd activity light indicator