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how can I fix a (no dial tone) modem problem?

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Full Member level 1
Jan 6, 2003
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problems & problems..... that's how we learn...

ok.. I have Creative PCI V90 modem... something happened to the phone line (I think high voltage chock) and after I got no dial tone message when I use it... the problem was: zener diad has beed dameged. so i change it and everything is ok now...
another modem stopped also... and the same msg... but everything (hardware) seems to be ok... I tried to listen to the line while modem tries to open port and connect, I heared some pulses not more than 4/sec... like if the modem tries to open but can not keep opening it...

What do you think the problem is??
the second modem is ACORP AMR1 65000...

thanks for helping

you may try to add
before dialing,
so for example it'll be
it'll help if something wrong just with dial tone
detection circuit

Easy..Your main relay is also damaged.Change it with a new one.Or try to shake contacts with a magnet.


{ok.. I have Creative PCI V90 modem something happened to the phone line (I think high voltage chock) and after I got no dial tone message when I use it... the problem was: zener diad has beed dameged}
its god speaking too you

telling you by way of a localise lightning or vsht discharge that has fryed your chipsets triger enable

you need too fully unscrew it and remove this modem

open the nearest bin!!!! :p

and place it gently in the bin
counting your blessings the zener did the job it did

while with the other hand placing a brand new v92 modem in the slot
then you'll get more like isdn speed at no extra cost 10-12k up dn

and also you get much more resorces if you dont use an irq driven codec modem made thrid party by creative a music audio company

the best modem is intel if you use intel chips and external
or for via try an external

then it wont hog a system irq
youll gain an extra 20 % speeds and less resorce = faster apps

good luck

but bin the crap modem and get less stress {your hair will fall out} :D

aha!! bin.. thank you... i didn't think about it!!!

I want to tell you something... money is not what i'm asking for.. I'm not intrested in this modem at all!!! but I want to fix it to live the sperite of succes... I want to fix it just for fixing... to learn more...

hope you get my point.

hahahaah lol:)

ok well

ill try too help you

first thing too do is see how the codecs health is using a tool for modems {from the chipsset makers site} and generic drivers from creative or use windows defaults}
or you can fire strings at it too test each part

if there is no dial tone then the signal that switches the relay {if it is descrete the fet or transistor} that comes after the diode is missing or the device is gubbed some modems use two fets and one pnp transistor to switch the line on and off
remember you remove the short too activate the line

to test it in circuit do this
take the card out
place a multimeter on diode test
place the + to the base or gate f the transistor to test with collector and emiter for a short
you should have one or a very low 33R resistance depending on the setup of the socket

there will also be a couplng coil too couple accross the modulation from the chip
but as you know you wont get anywhere without first the card being able to pick the reciever up

for this you need two signals the line signal {always there} and the picked up ring tone}
now we know that is says no dial tone
?but does it pick the line up

if it does {you can dial the line then dial on the cpu if the ringer on the phoen stops then the switching works
and its the demodulator limiter
thats the problem the first audio stage maybe the coil has fried so replace it

for switching problem
so once you establish this is switching on and off check for a short too gnd on the collector of the switchers and also for a voltage{ to run the transistor} is being developed by the regulator on the card for a pci card it has a 5 v regulator
sometimes these have a zero R links {look like chip resisotors}

these go open circuit disabling the whole ringer detection and switching supply

the rest is

1} if you get switching {you can add a wire to a point then plug it in and test the end}
its primarily another componet check for short caps and shorted arrester {like a little metal can with two end cups}this should be an open circuit too> 2kv then it will flash
it has a ceramic cup sometime a flash kills it and it melts going short
{if you plug in a phone and listen too the line try ringing the phone and seeing if it answers once set too answer mode}

also check the very thin gold contacts at the socket

sometimes they get melted {you could chase that one for a while}

so...... other than that it mentioned in a topic above

take a good quality scan or picture of each side {with any plastic housings they have removed}

and pm these too me see if i can spot the fault {there is so many types familys of familys of modem}

I think it will be impossible to repair it. The phoneline has probably been hit by lightning and all semiconductors are damaged.

It is not possible ;) There are lots of modem repair service here.Don't be sure that all semicond. are damaged.Try to work it on your computer.If your OS sees your modem but can not receive dial tone, you are lucky.Change zener diodes with EQUAL or ORIGINALs (I am using capitals, coz you must pay attention) Then change relay with (again) equal or original one.Be sure that you can fix your modem like this.Further questions, ask me via pm.

It will be much cheaper to buy a new V.92 modem.

Yea, maybe you are right but everything is not money in this world ;) By the way zener diodes $0,02, relay is under $1 here.The total cost is under $1 again. :D

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