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Old 6th Oct 2014, 10:43 am   #21
Joey0027
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Default Re: GPO 746 No Dial Tone

Thank you..that's a useful diagram.
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Old 6th Oct 2014, 11:30 pm   #22
Joey0027
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Default Re: GPO 746 No Dial Tone

Quote:
Originally Posted by Nickthedentist View Post
You can certainly check the resistors, the two "bulbs" and the microswitch contacts easily enough with a meter.
I've tried to follow the wiring diagram to the best of my knowledge & checked the resistors & all the readings are pretty close to those given. I have also checked the bulbs & they both show about 4 Ohms. With regards to the switch, when I put a meter across the top right & bottom right solder joints (terminals 1 & 2 I believe?) I get about 0.5 Ohm & when the switch is depressed no reading.

Is there a particular area that I need to be looking at with the no dial tone fault?

What are C1/C2 & C3? Should I be getting any readings across these?

Many thanks.
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Old 14th Oct 2014, 6:13 pm   #23
Joey0027
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Default Re: GPO 746 No Dial Tone

Any further suggestions or should i just call it a day & scrap it?

Many thanks.
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Old 14th Oct 2014, 6:18 pm   #24
Nickthedentist
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Default Re: GPO 746 No Dial Tone

It's difficult to diagnose this kind of fault remotely.

You could try bypassing the regulator section by soldering-in links which short-circuit each of the little bulbs.

If this is not successful, don't scrap it. Put it to one side. It may yield useful parts for a repair one day, or you might find the fault when you become more experienced with this kind of thing.

If you really don't want it, offer it here. Someone will have it, I'm sure.

N.
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Old 14th Oct 2014, 6:23 pm   #25
Joey0027
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Default Re: GPO 746 No Dial Tone

Thanks Nick.

Soldering for me is a big no no! That's one of those things that I never seem to get any better at with practice!

I'll put the board to one side for now.

Thanks for all your help.
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