RZ37LZ55 LG LCD Power Supply Repair Kit 6709900002A

The 6709900002A power supply fitted to the LG RZ37LZ55 does have some reliability issues. Failure of this power supply is common with the resulting symptom that the set is completely dead or stuck in standby. The power supply often fails at switch on and can be accompanied by an all mighty bang. The bang is due to the switching device IC904 failing. This device is an STR-T2268 and you may find that part of it has blown off. The reason for failure is defective SMD ceramic capacitors. After replacement of  three SMD ceramic capacitors, a zener diode, an SMD resistor a fuse and the afore mentioned STR-T2268 full working order will be restored.

Please note this kit consists of the parts required to repair the power supply. It is your responsibility to fit them and this can only be done by persons with experience in the repair of electrical equipment. A good degree of soldering skills is also required.

Many of these repair kits have been used in our workshop for the repair of this power supply with a 99.9% success rate.

The kit contents are as follows:

• F901 - T5A 20mm fuse
• IC904 - STR-T2268
• C920 - 220nF SMD capacitor
• C921 - 4.7uF SMD capacitor
• C924 - 1uF SMD capacitor
• R920 - 330R SMD resistor
• ZD911 - 1N5226B 3.3V zener diode

The repair procedure is to remove the power supply from the set and identify all the components supplied in the kit. All of the components are very close to the STR-T2268. On some boards anti moisture varnish surrounds the area of IC904 print side. It is important that this is all carefully picked away with a pin or sharp knife before desoldering or resoldering any components.The photographs show the location on the board of each component. It is very important to establish all the components positions before you start work. It is further advised that only one component is changed at a time. The process is straight forward for those with good soldering skills. Please note that some reforming of the legs on the STR-T2268 may be required and that ZD911 is mounted on the component side of the board. ZD911 is obscured by C918 a large brown capacitor. ZD911 is a polarised component, ie it must be fitted the correct way round. The three capacitors and resistor are not polarised. The STR-T2268 cannot be fitted incorrectly.

After fitting all the components all your work should be double checked. It is important to ensure that there are no solder splashes. Some of the components are close together and this is an easy mistake to make. If you do make a mistake then it is likely that the power supply will fail at switch on.

For those not able to fit the repair kit we can do it for you. We have a quick and efficient board exchange / repair service. Get in touch for more details.