Drayton Digistat SCR Wireless
Receiver Repair Capacitor – Iskra KNB1530 0.68uF
If your Drayton Digistat SCR is not working correctly it may be due to a common fault where the capacitor inside the receiver becomes
defective over the life of the product. The capacitor is soldered to the circuit board inside the unit and can be replaced to rectify the problem.
This Iskra capacitor
is direct replacement for those used in Drayton, British Gas and Iflo branded wireless thermostat receivers.
Iskra are the exact
supplier for these wireless systems and replacing with an original equipment
manufacturer part ensures that the unit will operate as the manufacturer
intended.
Description
This capacitor can be replaced by a competent DIY-er but it is recommended you use an electrician if you have any doubts.
Fitting instructions are at the end of this listing and can be e-mailed on request.
This fix is a cost effective solution and extends the life of the receiver saving the need for an expensive replacement unit.
Depending on the year of manufacture an Iskra KNB1530 or KNB1560 0.68uF capacitor was used inside these units. The difference between these two item numbers is the size of the capacitor plastic casing. The capacitance value of the component is exactly the same. The item in this listing (Iskra KNB1530 capacitor) was used in the original design of receiver units and so it is a suitable replacement for all units.
Click HERE for our PDF Repair Guide
Delivery
Free Postage and Packaging - 1st Class Delivery
Items are processed 6pm to 9.30pm - Monday to Friday. They are then dispatched the next working day.
ATTENTION: This E-bay listing is for the supply of capacitors only. Any repair
attempts you do are at your own risk and any information contained in this
listing is for general information purposes only. The free DIY repair guide is
available to download in PDF format (no purchase necessary). Only the
component/s are mailed out.
Drayton Digistat SCR & British Gas WR1 Wireless Receiver Repair Guide
This Drayton Digistat SCR repair guide details how to replace a faulty capacitor on the circuit board within the unit. This will fix the common problem where the unit indicates that the heating is on but the switching relay does not click to turn the heating on.
If you are following this guide you do so at you own risk.
Tools & Parts Required
1 x Drayton Digistat SCR Wireless Receiver
2 x Flat head screwdrivers
1 x Replacement Capacitor
(Iskra KNB1530 0.68uF)
Basic Soldering Skills
Soldering Iron
Solder with flux core
De-Solder Braid (optional
& not pictured)
Small wire cutters
Scalpel knife
Repair Procedure
Turn off your electric before removing the receiver from the wall back plate that is near your boiler. There should be an isolator switch near to the receiver or turn off all the electrics at the main fuse box for your house.
Remove the Digistat receiver from the wall plate by undoing the two small screws on the base of the unit and when loose the unit can easily be removed.
Turn the unit onto its front face. There are four tabs on the unit that need to be released to separate the two halves of the unit. The plastic is thin and so some light cosmetic damage may occur. This will not be a problem as when the unit is back on the wall it will never been seen.
With one screwdriver carefully push
out the wall of the casing whilst at the same time using the second screwdriver
carefully get it into the join of the two halves and leaver the back section of
the casing upwards. When the back of the casing is above the locking tab you
can move on to the next tab and repeat the process. Be careful not to insert
the screwdriver in too far as on some versions of PCB the radio transmitter
circuit is close to one of the tabs and damage can be caused.
Do the same procedure for all four tabs and the unit shall be in two halves. The tabs will now catch on the circuit board so just flex gently the side of the casing with your fingers and then the plastic back plate and circuit board will come apart from the front section of the case.
There are now two more plastic clips holding the circuit board to the casing. Release the small clip first and then the larger one. Be careful with the exposed circuit board to avoid damage. Handle the board at the edges rather than the main surface.
With the circuit board free it can be turned over and the capacitor that requires replacement can be seen. Place the circuit board carefully on to your work surface.
Using a flat blade screwdriver gently prise the capacitor up from the circuit board. It is held with a sticky pad that is used to hold the capacitor in place during the manufacturing process of the unit and shipping.
Units may now have the capacitor glued solidly to the board which are harder to move. The screwdriver method will not be sufficient on its own in this case. You will need to carefully and gradually cut into the glue using a scalpel or Stanley knife. Start at the corners of the capacitor and gradually work towards the middle. It puts the PCB under some stress so be careful only to apply enough force to aid the cutting of the glue. Be very careful of nearby components and your fingers.
(Edited Jan 2014. Thank You to M.Bishop for this information and technique)
There are two methods for de-soldering the capacitor from the board. If you have solder braid or a solder sucker removal tool then you can remover the solder with these items and then remove the capacitor. If you do not have these items then there is a method that you can follow without using them.
Turn the circuit board over and identify the two connections that are for the capacitor. Apply heat with the soldering iron to the connections whilst applying light pressure with the screwdriver to pull the capacitor out. You will have to alternate between the two connections moving it a little bit at a time with each. The capacitor will eventually come free from the board.
Bend the leads on the new capacitor at 90° to the plastic casing and cut the leads to approximately the same length as the old ones. A few millimetres longer is ideal to give sufficient lead length to solder to. You don’t want to cut the leads after they are soldered as this can cause the solder joint to crack.
Offer the capacitor to the circuit board contacts and if the holes are clear push the leads in and the put the capacitor in place flat to the circuit board. If solder is blocking the holes you will have to heat the solder in the holes whilst applying a little pressure to the capacitor to push the leads in. You will need to alternate again between the two contacts until the capacitor leads are in sufficiently.
You may then need to add a little solder to each contact depending on which removal method you followed.
This is an example of a good solder joint. There is not too much solder and it is volcano shaped. To achieve this heat must be applied to the lead and then the pad for the solder to stick to both surfaces.
Please visit YouTube for basic soldering technique.
With the capacitor now replaced the unit can now be reassembled. Insert the circuit board back into the back plate with the clips and then offer that assembled half to the front casing. Be careful to ensure the buttons are correctly seated in the casing. When they are together push the two halves until all four casing clips are fixed.
The receiver unit is now fixed and it can now be replaced on the wall mounting plate next to the boiler. Once the two fixing screws are done up the power can be restored to the boiler and you can enjoy your now working central heating.
Technical Data
Manufacturer -- Iskra Kondenzatorji d.d.
Construction -- Polypropylene film, metallized
Part number -- KNB1530
Capacitance -- 0.68uF
Operating Voltage -- 275 VAC
Class -- X2
Tolerance -- ±10%
Length -- 32mm
Height -- 20mm
Width -- 11mm
Terminal Pitch -- 27.5mm
Terminal Length -- 30mm ±5mm
Terminal Diameter -- 0.8mm
Component Datasheet
This E-bay listing is for the supply of capacitors only. Any repair attempts you do are at your own risk and any information contained in this listing is for general information purposes only.
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