Help with Landline telephone

[Navivanuva]

I have a home telephone that doesnt work properly. The problem is that the "off hook tone" doesnt stop even after i hook the handset.. I checked the switch inside and it works good. Any ideas? Thanks

 

[KrisBlueNZ]

Could be several things.

1. It could be something else connected to the line. Either try a different phone in the same socket, or take that phone to someone else's house and try it there. Just to confirm the problem is in that phone.

2. Take some photos of the inside of the phone. Include a closeup of the circuit board.

To attach photos to your post: Each photo should be in JPG format and no larger than 140 kilobytes. Click the Go Advanced button, and click the paper clip icon in the toolbar above the text area. On the Manage Attachments dialog, click Browse, select the file, and click OK. Repeat this for the other files. Click Upload. When the files have appeared in the Current Attachments area, scroll to the bottom of the dialog and click OK.

3. Do you have a multimeter?

 

[Navivanuva]

I've checked the line with other telephone and the line is good. I also tried the phone in my friend's house and the probem persisted.

I have attached the picture of the pcb inside the phone

Yes i have a multimeter.

Also i have tested the switch in the phone. The switch is working properly.

 

[Electric Al]

Probably not worth repairing !

Replace it . Phones are cheap !

 

[KrisBlueNZ]

It won't be economical to repair but sometimes people want to learn. Or reduce their e-waste.

But to be honest, diagnosing the fault would be a lot of work for both of us, unless you can draw up a schematic from the board. Do you have any electronics experience? Do you know what all the components are on the board? Can you draw up a schematic?

If not, we could both spend literally dozens of hours on it, and although I like to help with repairs, and I do have spare time, I really don't have that much for a repair to a cheap device like that. I hope you understand.

 

[davenn]

................

Also i have tested the switch in the phone. The switch is working properly.

despite your assurances...
I can almost garantee the switch ISNT working correctly !!

Dave

 

[kpatz]

If you think the switch is working ok (did you test it with a multimeter?) perhaps the switch controls some other circuit that handles the on/off hook. Have you traced where the switch wires go on the board?

Normally the switch is in series with the phone line (after the ringer circuit), and then it goes through a transformer coil and the other side of the transformer goes to the mic and speaker. So if the phone is staying off hook, the switch is staying closed. When you say you get the off-hook sound, do you get it on that phone or on another one?

 

[Navivanuva]

Thanks for the replies... I know it isnt economical to fix it, but i am just curious and want to learn. Sorry but i dont have the schematic of it.
I resoldered all connections just to be sure, and now the off hook tone stops when the switch is pressed. But now there is another problem. When i connect the phone and pressed the switch (just like when the phone is on hook), calls cannot come in. Also When i try to press the number to make a call, there is no sound, and calls cannot be made..

Well, i know the basic electronic components like transistor, capacitor, resistor, diode, etc.. I fixed a few phone in the past ..

Thanks guys..