Nokia 5110 Speaker problem

[Albinus]

Hey guys,

While I know a fair bit about various mobile phone technologies, I know bugger-all about their internal workings. Ever since I got my Nokia 5110 (second-hand off a friend), it works fine except that when I hold the phone to my ear, the speaker picks up the GSM pulsing noise (like when you hold an active GSM mobile near a cheap set of speakers). It's not that bad, but rather distracting at times.

I pulled the phone apart, and looked at the speaker, it's about the size of an Australian $2 coin. Does this interference indicate a faulty speaker? Or does it mean I need more shielding somehow? I don't want to order another speaker and find it won't fix the problem LOL

Any ideas guys? :?:

[Beefy]

My sister and I both have 3210s, hers does the same thing u just mentioned, whereas mine works fine.. it's got me buggered...

[Bahamut Zer0]

5110s, 3210s and in some cases the 3310s all exhibit similar faults due to their age. 5110 especially as it is a very old model phone. Typically the screen goes first, or the antenna. A good majority of my mates all have 3210 model phones and are getting the speaker problem as well, and those who still own a 5110 have faulty screens.

Anyway, you can try taking it to your mobile shop and get them to give you an assesment of whats wrong. Mobile phone techs know their stuff, and deal with faulty/shoddy nokia gear pretty much all day long. :)

Most cases its just loose/damaged cabling/connection from speaker to pcb.

[Beefy]

old age? the 3210s aren't THAT old.. :) and with mine / my sis's phones.. hers is only 8 months old.. mine's like 1 1/2 years..

[Albinus]

Well I got the phone in November last year, complete with a new screen so that *hopefully* won't be a problem for a while.

The connection from the speaker to the PCB is actually a "push-down" one, where the speaker is held in place by the phone's frame and makes contact via two little pins on the bottom. But I just wonder why I keep getting interference noise :?:

The speaker still picks up the noise even when I use an external aerial (car kit)... so it's not a faulty aerial on the phone methinks.

Thanks anyway guys :wave:

[tangcla]

The speaker prob doesn't have anything to do with the age of the phone, from my experience. It occasionally happens on my 8310, and that's new as! :D

It's got to do with interference. Haven't had time to figure out any more than that. Maybe if I get the time, I'll turn it into a theorem -- like some dude spent a few years proving a theorem that on a graph between any point, there will be a point of zero gradient :)

[jquirke]

TDMA interference can be caused by

*dirty PCB

*insufficient force holding phone together (for example, 8210 requires a torque of 17 Ncm on screws, not sure for 5110 - imagine it would be greater)

* Leather case with metal clip on back

* Charger plugged in

[Albinus]

TDMA interference can be caused by

*dirty PCB

*insufficient force holding phone together (for example, 8210 requires a torque of 17 Ncm on screws, not sure for 5110 - imagine it would be greater)

* Leather case with metal clip on back

* Charger plugged in

Wow, you seem to know what you're on about

The PCB is clean, I pulled the phone apart and cleaned all the contacts with special contact cleaner and no physical damage was noticed. Insufficient torque? Well the screws are tight enough to hold it in place, not as tight as mechanics do up oil bolts

I have tried without my case, same result. And no difference is noticed with the charger in (or out).

My Data Comms teacher said it's probably caused by poor shielding or a faulty capacitor (it's the amplifier picking up the interference apparantly - not the speaker). So I might have to find a good GSM phone repairer...

[jquirke]

Wow, you seem to know what you're on about

The PCB is clean, I pulled the phone apart and cleaned all the contacts with special contact cleaner and no physical damage was noticed. Insufficient torque? Well the screws are tight enough to hold it in place, not as tight as mechanics do up oil bolts

I have tried without my case, same result. And no difference is noticed with the charger in (or out).

My Data Comms teacher said it's probably caused by poor shielding or a faulty capacitor (it's the amplifier picking up the interference apparantly - not the speaker). So I might have to find a good GSM phone repairer...

Yes that's correct it's not the speaker, its the audio amplifer picking up RF signal (TDMA beats) from the radio circuit. You can prove this with a handsfree.

However, for a 5110, unfortunately, unless it is easily fixed it is probably not worth fixing :-(

[Albinus]

You can prove this with a handsfree.

Well actually, I got a handsfree and the noise isn't there! Any ideas... could it be the speaker? And I used a patch cord as well so I don't think it's the antenna either :?:

[jquirke]

Well actually, I got a handsfree and the noise isn't there! Any ideas... could it be the speaker? And I used a patch cord as well so I don't think it's the antenna either :?:

Well that is really interesting - I suspect the circuit to the speaker then is not well shielded - remember the speaker is close to the antenna/RF interface.

I suppose it wouldn't hurt to try another speaker, although I suspect it won't remedy the problem. Why not borrow a speaker from someone with a 5110 just to see..