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Hi,
The HAWCO unit is the main part of the controls for the Mk1 & MK2 Rayburn Nouvelle Boiler Burner. Its now obsolete, difficult to find and loads of money.
Ours started clicking on and off during the burner power down cycle. The Rayburn still worked so I left it. The clicking slowly got worse, going on longer. I thought about replacing the entire set of controls with the latest controller board but that's £1000 I'd prefer not to spend.
So I took the HAWCO unit apart and discovered that there are 4 blue electrolytic capacitors inside. From experience I know that these type of capacitors can dry out over time and lose capacitance. I checked them and found that all 4 were about 10-15% of their marked values - which explained the clicking behaviour. I replaced them with ones from my component supply and it now works perfectly. You need to be able to solder to do this.
The marked values on the old ones were
4u7 63V
47u 10V
100u 10V
100u 40V - this is the physically much bigger one. Its used to smooth the power supply.
The capacitors are readily available online. You might have to buy packs of 10 rather than individual components but I'd expect to pay no more than about £10 for the lot. Just make sure you match the capacitance, voltage rating and physical size for each one. The capacitors are polarity sensitive so make sure the - symbol matches the orientation of the one you take out. Taking a photo before you start is a good way of remembering which way round it goes.
Unfortunately I didn't think to take photos of the unit before repairing it, but attached is a picture of the 4 removed capacitors
The HAWCO unit is the main part of the controls for the Mk1 & MK2 Rayburn Nouvelle Boiler Burner. Its now obsolete, difficult to find and loads of money.
Ours started clicking on and off during the burner power down cycle. The Rayburn still worked so I left it. The clicking slowly got worse, going on longer. I thought about replacing the entire set of controls with the latest controller board but that's £1000 I'd prefer not to spend.
So I took the HAWCO unit apart and discovered that there are 4 blue electrolytic capacitors inside. From experience I know that these type of capacitors can dry out over time and lose capacitance. I checked them and found that all 4 were about 10-15% of their marked values - which explained the clicking behaviour. I replaced them with ones from my component supply and it now works perfectly. You need to be able to solder to do this.
The marked values on the old ones were
4u7 63V
47u 10V
100u 10V
100u 40V - this is the physically much bigger one. Its used to smooth the power supply.
The capacitors are readily available online. You might have to buy packs of 10 rather than individual components but I'd expect to pay no more than about £10 for the lot. Just make sure you match the capacitance, voltage rating and physical size for each one. The capacitors are polarity sensitive so make sure the - symbol matches the orientation of the one you take out. Taking a photo before you start is a good way of remembering which way round it goes.
Unfortunately I didn't think to take photos of the unit before repairing it, but attached is a picture of the 4 removed capacitors
Attachments
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