Potterton Prima 80F suspected electrical problem?

Hi There,
3 or 4 weeks ago my trusty 12 year old Prima 80F boiler stopped working. At the time I gave it a (small well calibrated) thump. It started working again and I thought no more of it.
Today it failed again. In the specific failure mode:
...The controls are calling for heat. ...The pump is running and the fan is on. ...The pilot light is lit ...but no main burner.
I took off the bottom cover and can see the gas valve is connected to the electrical control PCB/gubbins by a 4 way MOLEX style connector.
* If I carefully wiggle this connector the main burner lights straight away. * If I turn down the temperature control it turns off the main burner as you would expect. * When I turn up the temperature the boiler *sometimes* returns to the failure mode.
I sense a dodgy connection or a dry joint.
Q. Is this a common failure mode? Is there a specific connector or component that is the most common source of this problem. The benefit of your experience is appreciated!
David
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On Mon, 03 Apr 2006 23:03:11 +0100, Vortex wrote:

You've found the fault. You might be able to make a repair with your soldering iron. I've seen this fault on similar models.
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Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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I had a similar fault on a Potterton profile.
The pc board connector pins had dry/cracked solder joints. As someone suggested, at the time, you need a magnifying glass to spot which pins need re-soldering. Go easy on the heat applied as softening the plastic part of the connector is very likely:-(
There was quite a long thread here last Christmas, but I think you already have the conclusions.
regards

--
Tim Lamb

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writes [snip]

Guys thanks for confirming my suspicions.
This morning I have unplugged and replugged all the connectors. Right now "it just works".
If/when it fails again I'll rework the solder joints.
Thanks again,
David.
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