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mahjongg
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Re: USB Port Current Boost

Sat Jul 14, 2012 6:11 pm

Went ahead and tried this verbatim. Wireless adapters work in either port and everything just... works. No capacitor upgrade was needed.
Thats what I was talking about! :D
Glad that what I proposed is confirmed working. :ugeek: :roll:
1 Ohm is indeed a lot better than seven Ohm, but note that its still generating a 0.1 Volt drop for every 100mA. So if your PSU is on the edge, and only delivering 4.8 Volt to the PI, a 0.1 Volt drop is still significant.
If its not generating any hot plug (reset) problems lowering the value even more is recommended, maybe not to 0.001 Ohm, but maybe half an ohm, but using a better PSU would be a better solution in such cases.
Note that the resistor will not dissipate a lot of heat (as it should, unless there is a short), so a quarter watter is not needed, as these are generally larger than the polyfuses, so you can also use a tinier 1/8 or 1/16 Watt resistor, perhaps a 1206 SMT resistor will fit.

But do note that soldering resistors to the polyfuses will void your warranty, and may also overheat the polyfuses themselves (not that it matters, unless you remove the resistors again, and do not wait for the polyfuses to recover).
remember the polyfuses are made to be soldered to the board, so heating them up this way won't do much permanent damage, unless your soldering lasts several minutes and the polyfuses literally melt from the board. If your soldering skills are particularly poor I won't recommend this patch.

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Re: USB Port Current Boost

Sat Jul 14, 2012 7:22 pm

Lob0426 wrote:That is good news. Did you plug and unplug to see if your RasPi was resetting?

I just checked my USB polyfuses F1 is 7 ohms :shock: , F2 is 5 ohms and F3 is .001.
So 1 ohm is a lot better than that. :lol:
I did. Hot-plugging is working as expected for all devices. =D

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Re: USB Port Current Boost

Sat Jul 14, 2012 7:27 pm

mahjongg wrote:But do note that soldering resistors to the polyfuses will void your warranty, and may also overheat the polyfuses themselves
Yeah.... I just grabbed 2 irons and removed the polyfuses so they were not in the way of making my resistors nice and flush.

Warranties are just silly on a $35 device anyway. Not even worth my time to fill out the paperwork and pack it up. I'd just order another one ^_^

In any event I think I will pick up several different lower value resistors and experiment a bit, see what the lowest value that still works well is. Thanks for the tips.

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Re: USB Port Current Boost

Sat Jul 14, 2012 9:44 pm

I was using the wrong scale for my checks. F1 is 7.4 ohms, F2 is 5.9 ohms and F3 is .8 ohms so my F3 is well below specs, but F1 is well above specs. F2 is just inside specs for most SMD resettable PTC's. I do not have any 1 ohms here. Radio shack probably does not have them in store either.
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Re: USB Port Current Boost

Sat Jul 14, 2012 10:10 pm

lrvick wrote: Warranties are just silly on a $35 device anyway. Not even worth my time to fill out the paperwork and pack it up. I'd just order another one ^_^
What?? Where is the imperative on the part of a manufacturer / supplier to improve their product or service if you remove that particular feedback loop?

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Re: USB Port Current Boost

Sat Jul 14, 2012 11:10 pm

gritz wrote:
lrvick wrote: Warranties are just silly on a $35 device anyway. Not even worth my time to fill out the paperwork and pack it up. I'd just order another one ^_^
What?? Where is the imperative on the part of a manufacturer / supplier to improve their product or service if you remove that particular feedback loop?
Yes yes... point taken. Just not something that is going to hinder anyone considering modding,

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Re: USB Port Current Boost

Mon Jul 16, 2012 3:08 am

lrvick wrote:
gritz wrote:
lrvick wrote: Warranties are just silly on a $35 device anyway. Not even worth my time to fill out the paperwork and pack it up. I'd just order another one ^_^
What?? Where is the imperative on the part of a manufacturer / supplier to improve their product or service if you remove that particular feedback loop?
Yes yes... point taken. Just not something that is going to hinder anyone considering modding,
@Gritz:
Warranties are not silly if you are one of the ones that had to wait 4 months and yours showed up not working. But you do have a point after you know it works OK. ;) I am waiting for a second RasPi to show up before I dig out the Soldering Iron. A Raspi in hand that works is worth, buying two for $200 dollars each on Eprey. (Ebay)
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Re: USB Port Current Boost (solved)

Sun Jul 22, 2012 10:40 pm

Small world. I too am using an N10 wifi, along with a blue tooth (directly in USB2), a 4 port hub (USB1), and a Logitech "unified"* wireless keyboard and mouse. I've not had any issues with the N10, or resetting, but I have been getting bizarre keyboard repeating. To be fair, I haven't been hotplugging anything either. Anyone know where to find mini fuses? While putting 1 ohm resisters across the polyfuses looks straight forward enough, I'd rather actually put the right size fuses on.
But so far I've not found a supplier that makes one to fit.

Also it's odd seeing talk about 700mA fuses. I have a 750mA fuse on my Pi. Also, I may have to rethink my psu, as I think I only ordered one rated at 2A, but currently using my cell phone charger to power it (850m).

* I really love the fact that Logitech did this. Two devices on one plug-in. But, I had been thinking that was the cause of my keyboard issue.

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Re: USB Port Current Boost (solved)

Sun Jul 22, 2012 10:47 pm

Your key board issue is the USB lib driver issue being talked about on the trouble shooting forum your stuck till some one fixes USB v1 or v1.1 only some of the USB 2 devices work ok with no errors but as there's no fix yet join the que
one armed controls engineer, my grammar is bad but lets face it most keyboards don't suit a one armed man

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Re: USB Port Current Boost (solved)

Sun Jul 22, 2012 10:53 pm

jackd wrote:Small world. I too am using an N10 wifi, along with a blue tooth (directly in USB2), a 4 port hub (USB1), and a Logitech "unified"* wireless keyboard and mouse. I've not had any issues with the N10, or resetting, but I have been getting bizarre keyboard repeating. To be fair, I haven't been hotplugging anything either. Anyone know where to find mini fuses? While putting 1 ohm resisters across the polyfuses looks straight forward enough, I'd rather actually put the right size fuses on.
But so far I've not found a supplier that makes one to fit.
Well, this one should fit, and would be a great improvement:
http://uk.farnell.com/littelfuse/1812l0 ... dp/2128235

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Re: USB Port Current Boost (solved)

Sun Jul 22, 2012 11:07 pm

Ignore my previous post. I found a suitable replacement, from the same company. A little higher than I'd like, the 500 might work too. I guess I wasn't looking hard enough. Now all I need to do is find a seller.

750
http://www.te.com/catalog/pn/en/RF1404- ... SMDC075F-2

500
http://www.te.com/catalog/pn/en/RF1403- ... SMDC050F-2

Resistance values are much better too. Should nicely solve everyones' problems without ugly patching. Also, a better solution for desoldering is to use a two pronged iron tip and tweezers (rather than two irons. Another possibility is desolder one side and while still hot gently push a wood toothpick under to lift the cap ever so slightly (note I don't recommend this approach. At All. I've seen it done and done it myself in a real pinch.). Also, if you're really into modding, you can drill a hole in two single tips, cut one in half, take a copper nail (plumbing supplies), and join the two, and voila you have an adjustable two pronged tip. I haven't tried using such a mod. YMMV. Although I doubt such a mod would fit in such tight places.

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Re: USB Port Current Boost (solved)

Sat Aug 04, 2012 12:15 am

I just received in some 1812 500ma and 1.1A poly fuses from Mouser. I will be trying to install them onto RasPi #1. #2 and #3 arrived the other day so it is time to heat up the Irons. We will see what a RasPi can do and how it behaves with these larger fuses. It will be interesting to see if these fuses have enough resistance to cure the inrush, without too high of resistance. They are spec'ed at a lower resistance than the current 140ma fuses (at least on my RasPi #1 5.9ohm and 7.2 ohm).
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Re: USB Port Current Boost (solved)

Sat Aug 04, 2012 3:43 pm

Isnt there also a polyfuse on the intake voltage as well? To stop the SOC from being overloaded.

If you replace the 140mA ones on the USB ports you might just allow the USB ports to draw too much current and cause the RPi to fail due to being underpowered. I'm sure there is a reason they used what they did.

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Re: USB Port Current Boost (solved)

Sun Aug 05, 2012 12:06 am

CCitizenTO wrote:Isnt there also a polyfuse on the intake voltage as well? To stop the SOC from being overloaded.

If you replace the 140mA ones on the USB ports you might just allow the USB ports to draw too much current and cause the RPi to fail due to being underpowered. I'm sure there is a reason they used what they did.
Yes the 1.1A polyfuse is for replacing the 700ma (750ma on my new boards) and the 500ma polfuses are for the USB ports. The 1.1A is what the original spec called for, though really the 750ma fuse is fine for that. The USB fuses would have been better at 350ma. This would have allowed most devices except HDD's to work directly from the RasPi. PiPass takes power directly to the USB ports without the fuse a fuse at all except the USB fuses. The fuse then only protects the SoC. I am trying tgo bring the RasPi up to a little better than original, Not totally reconfigure it.
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Re: USB Port Current Boost (solved)

Sun Aug 05, 2012 5:26 pm

Replaced the USB 140ma poly fuses with 500ma fuses today. No reset problems at all. Even plugged and unplugged a WiFi dongle and it worked fine, no reset.
Also replaced the 700ma (750ma on newer) with an 1100ma (1.1A) poly fuse. The RasPi will now light up a USB HDD, but the drive chirps. I believe this signals low volt to the drive. The resistance of the 500ma fuse is going up because the HDD is trying to draw more than 500ma, at least that is my guess. The USB HDD adapter that I am using has a "Y" power cable to it. When I plugged the HDD into both RasPi USB ports the chirping stopped and a dialog box in LXDE opened asking if I wanted to view the drive. Of course I could not open the drive as I had to unhook the wireless combo keyboard/mouse to use both ports. :lol: Plugged and unplugged the drive and no reset. So one port will not drive a USB HDD even with the 500ma fuses in place. This does open up the possibilty to run RasPi headless with a USB HDD connected now. By the way I swapped out the 1A iPhone charger for a 2A iPad charger for these tests.

Removing the old fuses looked like a daunting task that would take two irons. It is not that bad and you do not need two irons. I used a 15W iron and heated both ends of the fuses first. You need to do this as quickly as possible. Then I took the tip of the iron on the near side and gently pried up. This lifted the near end out of the solder. I then moved the iron to the opposite side and pulled towards me. The fuse then fell off. I used the iron to smooth both solder pads. Then I laid the new fuse on top of the pads. After lining it up I pressed the fuse down gently with a small screwdriver and applied the iron to the near side to melt the solder. I then did the same for the other side. This sticks the fuse down. I added some solder (.032" 60/40 Rosin-Core) to each side to make sure I had a good connection. I made sure I put solder on top of the fuse pads and dragged it down to the solder pads over the end of the fuse. The fuses I used are sized 1812.

Mouser Electronics P/N's
576-1812L110PRT (1.1A 6v) 1.1A Littlefuse PTC resettable fuses
652-MF-MSMF050-2 (500ma 15V) Bourns PTC resettable fuses

These fuses have a much lower resistance than the original fuses, especially the USB fuses. You should have less keyboard and mouse problems as the voltage to the devices is higher. You wil have to use a more powerfull PSU if you intend to use something like a USB HDD. My guess is at least a 1.5A PSU. That is above the rated amperage of the micro USB connector for two wires connected. That draw will not be continuous so it should work just fine.

Happy Modding All! :D
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Re: USB Port Current Boost (solved)

Sun Aug 05, 2012 10:21 pm

Lob0426 wrote:Replaced the USB 140ma poly fuses with 500ma fuses today. No reset problems at all. Even plugged and unplugged a WiFi dongle and it worked fine, no reset.
Also replaced the 700ma (750ma on newer) with an 1100ma (1.1A) poly fuse. The RasPi will now light up a USB HDD, but the drive chirps. I believe this signals low volt to the drive. The resistance of the 500ma fuse is going up because the HDD is trying to draw more than 500ma, at least that is my guess. The USB HDD adapter that I am using has a "Y" power cable to it. When I plugged the HDD into both RasPi USB ports the chirping stopped and a dialog box in LXDE opened asking if I wanted to view the drive. Of course I could not open the drive as I had to unhook the wireless combo keyboard/mouse to use both ports. :lol: Plugged and unplugged the drive and no reset. So one port will not drive a USB HDD even with the 500ma fuses in place. This does open up the possibilty to run RasPi headless with a USB HDD connected now. By the way I swapped out the 1A iPhone charger for a 2A iPad charger for these tests.

Removing the old fuses looked like a daunting task that would take two irons. It is not that bad and you do not need two irons. I used a 15W iron and heated both ends of the fuses first. You need to do this as quickly as possible. Then I took the tip of the iron on the near side and gently pried up. This lifted the near end out of the solder. I then moved the iron to the opposite side and pulled towards me. The fuse then fell off. I used the iron to smooth both solder pads. Then I laid the new fuse on top of the pads. After lining it up I pressed the fuse down gently with a small screwdriver and applied the iron to the near side to melt the solder. I then did the same for the other side. This sticks the fuse down. I added some solder (.032" 60/40 Rosin-Core) to each side to make sure I had a good connection. I made sure I put solder on top of the fuse pads and dragged it down to the solder pads over the end of the fuse. The fuses I used are sized 1812.

Mouser Electronics P/N's
576-1812L110PRT (1.1A 6v) 1.1A Littlefuse PTC resettable fuses
652-MF-MSMF050-2 (500ma 15V) Bourns PTC resettable fuses

These fuses have a much lower resistance than the original fuses, especially the USB fuses. You should have less keyboard and mouse problems as the voltage to the devices is higher. You wil have to use a more powerfull PSU if you intend to use something like a USB HDD. My guess is at least a 1.5A PSU. That is above the rated amperage of the micro USB connector for two wires connected. That draw will not be continuous so it should work just fine.

Happy Modding All! :D

So if I am doing to support an external drive directly via the usb port should I use more than a 500ma?

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Re: USB Port Current Boost (solved)

Sun Aug 05, 2012 10:50 pm

I've been following this thread for quite some time and I'm now ever-so-tempted to 'fix' this fundamental USB fiasco. However, I think a UK source of components would be better for many:

MERCHANDISE TOTAL: £1.02
Delivery Charge: £12.00
Order Total: £13.02

Excuse the lack of formatting but you'll get the gist. Three tiny components in a (used?) Airlight jiffy bag should be £1.70 by Recorded Delivery. A bulk purchase anybody?

EJ

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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 1:14 am

oakfan52 wrote: So if I am doing to support an external drive directly via the usb port should I use more than a 500ma?
You could try a 750ma polyfuse (that still is only 3.75 watts, but better than 2.5 watts). But you might have to run an even larger fuse for the power (Larger than 1.1Amp) Remember the RasPi uses some power too. And then there is the Micro USB connector that could limit the power input also. Most USB HDD's need at least 4w to operate.

A modified PiPass would be better, if you intend to run a USB HDD off of a single port. Run power from the input side of F3 into the bottom port (F2), possibly putting a .5 ohm resistor in line of the PiPass. This runs the power past the board and protect the traces which might just not hold up under a steady load if the HDD pulls above 500ma all the time. The other USB port will remain as original. A powered hub is realy the best answer for a USB HDD.

Either way you will have to use a more powerful PSU, like 1.5A TO 2A.
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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 1:58 am

ejsolutions wrote:I've been following this thread for quite some time and I'm now ever-so-tempted to 'fix' this fundamental USB fiasco. However, I think a UK source of components would be better for many:

MERCHANDISE TOTAL: £1.02
Delivery Charge: £12.00
Order Total: £13.02

Excuse the lack of formatting but you'll get the gist. Three tiny components in a (used?) Airlight jiffy bag should be £1.70 by Recorded Delivery. A bulk purchase anybody?

EJ
you only need comparable parts not the exact parts. Look for PTC resettable fuses. I found these at Newark and Digikey also. Newark was cheaper. I am sure you will find them at almost any components house. I would have ended up paying more for shipping than the parts but I bought some other parts along with these. If I order again I am going to search a little more for a better price and buy them 10 or more each.
Mfg. part #'s
MF-MSMF050-2; Bourn PTC Resettable Fuses 15V 100Amps (500ma PTC fuse 15v)
1812L110PR; Littlefuse PTC Resettable Fuses 6V 1.1A (1.1Amp PTC fuse 6v)
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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 9:33 am

Lob0426 wrote: you only need comparable parts not the exact parts. Look for PTC resettable fuses. I found these at Newark and Digikey also. Newark was cheaper. I am sure you will find them at almost any components house. I would have ended up paying more for shipping than the parts but I bought some other parts along with these. If I order again I am going to search a little more for a better price and buy them 10 or more each.
Mfg. part #'s
MF-MSMF050-2; Bourn PTC Resettable Fuses 15V 100Amps (500ma PTC fuse 15v)
1812L110PR; Littlefuse PTC Resettable Fuses 6V 1.1A (1.1Amp PTC fuse 6v)
Missing the point. Not everyone has a local Radioshack nor Fry's nor has a need to create a merchant account for additional electronic components. There could be a niche for selling the 3 polyfuses as a set on eBay.co.uk, with no shipping (sic) required, just post (not a sea vessel in sight).
[Yes, my powers of observation/Googling was capable of searching the parts numbers, thanks ;):p]

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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 11:14 am

How about a thankyou for the work he has done and shared with the community :roll:

Texy
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https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555

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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 12:55 pm

texy wrote:How about a thankyou for the work he has done and shared with the community :roll:
Texy
Yes, of course, a MASSIVE Thank You, to all the folks that are trying to get to the bottom of this.
8-)

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Re: USB Port Current Boost (solved)

Mon Aug 06, 2012 5:52 pm

ejsolutions wrote:
Lob0426 wrote: you only need comparable parts not the exact parts. Look for PTC resettable fuses. I found these at Newark and Digikey also. Newark was cheaper. I am sure you will find them at almost any components house. I would have ended up paying more for shipping than the parts but I bought some other parts along with these. If I order again I am going to search a little more for a better price and buy them 10 or more each.
Mfg. part #'s
MF-MSMF050-2; Bourn PTC Resettable Fuses 15V 100Amps (500ma PTC fuse 15v)
1812L110PR; Littlefuse PTC Resettable Fuses 6V 1.1A (1.1Amp PTC fuse 6v)
Missing the point. Not everyone has a local Radioshack nor Fry's nor has a need to create a merchant account for additional electronic components. There could be a niche for selling the 3 polyfuses as a set on eBay.co.uk, with no shipping (sic) required, just post (not a sea vessel in sight).
[Yes, my powers of observation/Googling was capable of searching the parts numbers, thanks ;):p]
There in lies the problem. I am in the U.S.
I have bought stuff from the U.K and had it shipped postal. About a month to get the stuff. And it cost more than these parts cost to get it. To ship any other way would be at higher cost than the components themselves also. I posted the part numbers so others can retrofit their RasPii. If you would like to source and retail the parts in the U.K. you are welcome to the enterprise. To ship here in the U.S it would probably cost at least a few dollars unless I dropped them in an envelope and put a stamp on it. No guarantee the parts would not be damaged or lost if done that way.
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Re: USB Port Current Boost (solved)

Fri Aug 10, 2012 12:31 pm

n00b question:
Why are you using 15V fuse? Shouldn't it be like 6V?
Is it ever going to trigger when it's operating voltage is 15V but the board runs @5V??
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Re: USB Port Current Boost (solved)

Fri Aug 10, 2012 6:35 pm

Stomp wrote:n00b question:
Why are you using 15V fuse? Shouldn't it be like 6V?
Is it ever going to trigger when it's operating voltage is 15V but the board runs @5V??
You will find that many of the components on the Raspberry PI have various voltage ratings. For the fuse I coud not find a 6v alternative, so I went up. That fuse will work just fine if an over-current is encountered.

Here are a few pictures of the fuses replaced. F2 is now a 700ma fuse (used to be F3 fuse on this board). The 500ma fuse was working just fine to power the RasPi through the hub. I was seeing low voltage at TP1/TP2 so I replaced the Fuse and it made no difference. The RasPi was just not meant to be powered this way, but it works anyway. :lol:
New USB fuses1.jpg
New USB fuses
New USB fuses1.jpg (33.78 KiB) Viewed 3191 times
Here is the RasPi runing with no PSU of its own. It is sending Data and RECIEVING power through just a single cable. The hub was modified by adding a power wire from the input to pin #1 of the USB Data connector. That pin was not connected at production. The red wires sticking out the side are so I can disconnect the power jumper. That way it can still be used as a normal hub.
hub powered.jpg
RasPi Power and Data through single cable to USB Hub
hub powered.jpg (52.35 KiB) Viewed 3190 times
And finally a screenshot of the RAsPi running from the USB hub.
No PSU screenshot.jpg
screenshot without PSU, powered by Hub
No PSU screenshot.jpg (45 KiB) Viewed 3191 times
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