Bios beeps volume too low to hear.
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From: Paul on 8 May 2010 23:27 VanguardLH wrote: > Paul wrote: > >> VanguardLH wrote: >>> John wrote: >>> >>>> This is not so much problem as an annoyance, but could be a problem if and >>>> when a problem does happen. >>>> >>>> Computer is home built - Asus P6T SE with the latest Bios installed (0808). >>>> The case is Lian Li PC-K58B and came with a small bud like speaker that >>>> fits direct to the motherboard. >>>> When booting, the one beep that happens on boot up is hardly noticeable, I >>>> need to have my ear next to the case to even hear it. I've changed the bud >>>> speaker to an 57mm cone 8ohm speaker in the hope that this would amplify >>>> the sound but to no avail, still hardly noticeable. >>>> I've checked though the Bios settings to see if the sound is adjustable but >>>> as far as I can ascertain this isn't possible. I've also enclosed the new >>>> cone speaker into a container to see if the volume would improve. >>>> Is there a way I can get around this problem by amplifying the volume of >>>> the speaker? Has anyone else come across this and if so how did you rectify >>>> the situation? >>> A speaker using a magnetically-driven cone won't work. >> That is not true. All of my computers here have magnetic speakers >> for "PC Beep" and work just fine. >> >> A sample drive circuit for "PC Beep", can be seen here on PDF page 32. >> >> http://www.intel.com/design/chipsets/designex/BXDPDG10.htm >> >> Redrawing the equivalent circuit, it looks like this. >> >> +5V ("VCC") >> | >> +------> >> "SPKR" >> +------< >> | >> 34 ohms >> | >> Logic level ____|/ 2N3904 >> |\ silicon switching >> > transistor >> | >> GND >> >> Maximum power transfer, occurs with a 34 ohm speaker. Maybe they selected >> that, to match well with a 32 ohm speaker. They use a cheap pair of >> resistors in parallel to handle the maximum power/heat expected >> of the circuit (like if you short the speaker terminals). >> >> The logic level signal, lacks the output drive, to drive the magnetic >> speaker directly. The 2N3904 can be run as a saturating switch, >> handling currents of up to 200mA. If it was operated in linear >> mode, it would fry. But saturated, with low Vcesat, even the >> physically small transistor they use, is sufficient. You have >> to check that the 3904 has sufficient current gain, for the >> application. >> >> Even when the circuit isn't perfectly matched, such as using >> an 8 ohm speaker in the circuit, if you do the math, the >> power level isn't significantly reduced. The speaker is >> still getting 0.11 watts or so into 8 ohms. >> >> A piezoelectric can also be used. I have no idea exactly what >> the equivalent circuit looks like for one. My experience is, >> they like lots of driving voltage, at less current than >> a magnetic speaker would use. I've driven my piezo >> headphones to high levels, using an opamp circuit. >> >> With regard to testing that circuit for correct operation, >> I don't see it being particularly easy for an end-user to >> test the '3904 transistor is working properly. If there were >> utilities that could force a logic 1 or a logic 0 onto >> the base of the '3904, it might be easier to characterize and >> verify circuit operation. I can't even be sure, looking at >> a motherboard, that I can find those components. They >> might be near the PANEL header, or they might not. In >> a picture of the P6T, I can see a number of transistors near >> the PANEL header. And no suspicious large resistors. >> >> To "amplify" that output, you would need an amplifier. And >> the amplifier would likely "click or pop" each time the computer >> was turned on. I would use this as a means to get an audio signal. >> The ceramic cap is present, for DC isolation. No amplifier >> necessarily appreciates DC coming at it. The choice of the >> 8 ohm resistor (or the nearest standard value close to that), >> gives a peak to peak amplitude of about 1 volt, which should be >> sufficient to drive a line-level set of amplified computer speakers. >> A 1/8" jack could be placed, where it says "to audio amp". You could >> connect tip and ring to the upper signal, and sleeve to the ground. >> If it still isn't loud enough, change the 8 ohm resistor to 33 ohms. >> The set of amplified PC speakers, would then be dedicated to the >> "PC beep" function. >> >> +5V ("VCC") >> | >> +------> --+ >> | >> 8 ohm resistor, 1/4 watt or 1/2 watt >> | >> +--- 0.1uF 25V cap ----> to audio amp >> | (assume 10K input >> +------< --+ +---> impedance) >> | | >> 34 ohms GND >> | >> Logic level ____|/ 2N3904 >> |\ silicon switching >> > transistor >> | >> GND >> >> There are other examples of "PC Beep" drive circuits. This one >> looks like an emitter follower. See PDF page 74. This would >> likely blow your eardrums out. I don't think this one is >> safe to short the SPKR terminals, whereas the first circuit above >> is short circuit safe. >> >> http://www.intel.com/design/chipsets/schematics/252812.htm >> >> See PDF page 118 here, for another example. This is similar to the >> first link, but with a different limiting resistor. This might not >> be very loud, but changing the resistor value could fix it. This >> might only be about 1/3rd as loud as the first circuit. >> >> http://web.archive.org/web/20061118133939/http://www.winbond.com/PDF/sheet/w83627hf.pdf >> >> Another problem, is figuring out what is driving the logic signal. >> I think you can get PC beep from some SuperI/O chips, or >> from the Southbridge. There might be more than one potential >> source on the motherboard. Trying to trace that circuit, wouldn't >> be easy. It would be easy to verify one leg of the SPKR pins >> is wired to VCC (+5). But for the other leg, you might have to >> ohm around for a while, to find the bit that connects to it, and >> then guess at the connected circuit topology. >> >> I checked the vip.asus.com forums, and I don't see a lot of complaints >> about problems with PC beep on P6T SE. Some people report they're getting a >> beep code, but at the same time, they're not complaining about the >> volume level of the beep. It could be, the OPs board has a fault, >> like a bad '3904. >> >> HTH, >> Paul > > My guess is that the problem was with a soldered-on button piezo speaker, > not with one connected to a 4-pin mobo header (which will usually take a > magnetically-driven speaker). With an integrated "buzzer", the driving > circuit probably won't handle the current load required for a magnetic > speaker. That's why the OP needs to replace the piezo speaker with another > one. There is no piezo. Just the white PANEL header in the lower left corner of this photo. The SPKR pins are on the lower right of the PANEL header. Four pin spacing (as shown in the manual). Even with this resolution of picture, it is pretty hard to make anything out, like what might be driving it. http://www.unitycorp.co.jp/asus/motherboard/intel/lga1366/p6t_se/big_photo.jpg Paul
From: Mike Easter on 8 May 2010 23:46 Paul wrote: > VanguardLH wrote: >> My guess is that the problem was with a soldered-on button piezo speaker, >> not with one connected to a 4-pin mobo header (which will usually take a >> magnetically-driven speaker). > There is no piezo. Just the white PANEL header in the lower left corner of > this photo. The SPKR pins are on the lower right of the PANEL header. > Four pin spacing (as shown in the manual). The OP got the buzzer/tweeter with his Lian Li case, it didn't come on the mobo. I got a buzzer with a Cooler Master case and it was just what I needed for the mobo the case was intended for. I assumed that the 'industry' practices or standards were that the responsibility for the mobo speaker lay with the case mfr/supplier, like the little case wired coil speakers of the past, and that the case people had assumed/ taken on/ the responsibility and decided to save money with little buzzers to 'stick onto' the mobo. John wrote: > The case is Lian Li PC-K58B and came with a small bud like speaker > that fits direct to the motherboard. -- Mike Easter
From: John on 9 May 2010 22:03 On Sat, 08 May 2010 20:46:11 -0700, Mike Easter wrote: > Paul wrote: >> VanguardLH wrote: > >>> My guess is that the problem was with a soldered-on button piezo speaker, >>> not with one connected to a 4-pin mobo header (which will usually take a >>> magnetically-driven speaker). > >> There is no piezo. Just the white PANEL header in the lower left corner of >> this photo. The SPKR pins are on the lower right of the PANEL header. >> Four pin spacing (as shown in the manual). > > The OP got the buzzer/tweeter with his Lian Li case, it didn't come on > the mobo. > > I got a buzzer with a Cooler Master case and it was just what I needed > for the mobo the case was intended for. > > I assumed that the 'industry' practices or standards were that the > responsibility for the mobo speaker lay with the case mfr/supplier, like > the little case wired coil speakers of the past, and that the case > people had assumed/ taken on/ the responsibility and decided to save > money with little buzzers to 'stick onto' the mobo. > > > John wrote: > > The case is Lian Li PC-K58B and came with a small bud like speaker > > that fits direct to the motherboard. Just to clarify the situation the existing buzzer is the same as shown on the link that Vanguard supplied: http://www.pcpartscollection.com/mosp.html I managed to source a replacement from an old computer a friend had in his garage but I'm afraid it made no difference to the volume. I'm an elderly person with some hearing defect so to check that it wasn't my hearing I got my wife (who can hear a pin drop at 50 metres) to listen when I booted up. She remarked that though she could hear the beep it was faint. I then tried three other computers (friends) to see if the volume was better or the same as mine, and found that they all had very faint buzzer beeps. In fact the owners of the other computers were unaware that computers beeped on boot up and had never noticed a beep when booting the computer. I read with interest the points that Paul made, but my expertise is not up to changing the motherboard circuit wiring. I wonder is it possible to amplify either a cone speaker or a piezo buzzer, between the motherboard connection and speaker/piezo?
From: VanguardLH on 10 May 2010 02:02 John wrote: > On Sat, 08 May 2010 20:46:11 -0700, Mike Easter wrote: > >> Paul wrote: >>> VanguardLH wrote: >> >>>> My guess is that the problem was with a soldered-on button piezo speaker, >>>> not with one connected to a 4-pin mobo header (which will usually take a >>>> magnetically-driven speaker). >> >>> There is no piezo. Just the white PANEL header in the lower left corner of >>> this photo. The SPKR pins are on the lower right of the PANEL header. >>> Four pin spacing (as shown in the manual). >> >> The OP got the buzzer/tweeter with his Lian Li case, it didn't come on >> the mobo. >> >> I got a buzzer with a Cooler Master case and it was just what I needed >> for the mobo the case was intended for. >> >> I assumed that the 'industry' practices or standards were that the >> responsibility for the mobo speaker lay with the case mfr/supplier, like >> the little case wired coil speakers of the past, and that the case >> people had assumed/ taken on/ the responsibility and decided to save >> money with little buzzers to 'stick onto' the mobo. >> >> John wrote: >> > The case is Lian Li PC-K58B and came with a small bud like speaker >> > that fits direct to the motherboard. > > Just to clarify the situation the existing buzzer is the same as shown on > the link that Vanguard supplied: http://www.pcpartscollection.com/mosp.html > > I managed to source a replacement from an old computer a friend had in his > garage but I'm afraid it made no difference to the volume. > > I'm an elderly person with some hearing defect so to check that it wasn't > my hearing I got my wife (who can hear a pin drop at 50 metres) to listen > when I booted up. She remarked that though she could hear the beep it was > faint. I then tried three other computers (friends) to see if the volume > was better or the same as mine, and found that they all had very faint > buzzer beeps. In fact the owners of the other computers were unaware that > computers beeped on boot up and had never noticed a beep when booting the > computer. > > I read with interest the points that Paul made, but my expertise is not up > to changing the motherboard circuit wiring. I wonder is it possible to > amplify either a cone speaker or a piezo buzzer, between the motherboard > connection and speaker/piezo? The unit that I linked to that showed a 4-pin connector to a bud buzzer meant you were using the 4-pin mobo header for the speaker connection. That should handle a *small* 8-ohm speaker. It looks like you have a flaw in the mobo regarding the driving circuit for the speaker. Oh well, if you didn't know what the beep counts meant (long beeps, short beeps, how many of each) then you aren't losing anything important to you that you could do anything about. Once the OS starts loading and it loads the audio drivers, your external speakers are going to get used, anyway. I know some Dells use the externally attached speakers for the warning buzzer instead of using one like you have. The POST beeps come through the powered speakers (so obviously you must have them powered to hear the beeps). I haven't bothered to read the online manual for your particular motherboard to see what it might support for sound issued through the backpanel connectors.
From: Paul on 10 May 2010 02:06
John wrote: > I wonder is it possible to > amplify either a cone speaker or a piezo buzzer, between the motherboard > connection and speaker/piezo? Sure. You could take something, like a "portable karaoke" machine, which has a microphone and a speaker, and hold the microphone inside the computer. But this will also pick up fan noise, computer noise, and generally be a bad idea. (You'd need to build an enclosure around the microphone and speaker, to keep out other noises.) You could try contacting Asus support, and see if they even know their P6T SE is a sub-standard design. Maybe they already know that some batch of boards, had the wrong value of resistor stuffed in them, causing the speaker level to be weak. I think a superior solution, is to rig up a circuit that connectors to the speaker pins. (Mainly, because the solution would be "quiet" when the beep interval was finished.) But to build that, you'll need to be a hobbyist, and have access to parts. And it doesn't sound like you're really that interested in doing that. I don't blame you. This should all be unnecessary. Paul |