Mitsubishi Flashing Timer LED

[lcaillo]

Some Mitsubishi sets, starting with the early models with ATSC tuning and digital inputs that use the DM modules, have been experiencing a problem with constant flashing of the timer LED and no power. This symptom indicates that the set has not completed the boot cycle that should take about 70 seconds whtn the set is plugged in or reset. This has often indicated a problem in the DM power supply that is caused by defective capacitors. Usually, the fix is to replace the 1000 uF capacitors in the DM module.

Unfortunately, Mitsubishi has been slow to recognize this problem and from the start on these sets recommended replacing the DM for any such problem. The original intent was to "dumb down" the repair process to make it easier to service the sets, reducing all problems to board level repair. Many techs have become accustomed to this type of service, as many manufacturers are moving away form field repair at the component level to board swapping. This makes repairs cost prohibitive in many cases. For instance, the DM for a WS-65813 retails for $435.00. Add labor charges and you have a very expensive repair. Fortunately, many sets can be fixed just by replacing a handfull of caps, if the tech is willing to do his homework, or if one is willing to DIY.

Apparently, Mitsubishi got a supply of sub-standard caps. All of the caps than tend to fail are Jamicon made, and seem to fail by an increase in dielectric absorbtion, followed by d.c. leakage, overheating, then swelling and losing capacitance. The problem may occur before the caps swell in an obvious manner, and may be present even with the set working normally. The problem often shows up only after a power outage or when the set is unplugged. The set will often run normally with capacitors in very poor condition and not present a problem until a boot cycle is attempted.


A very good guide for the WS-xx813 sets:
http://www.fixya.com/howto/h159332-m...m_board_repair

And for a WS-xx859:
http://www.jeremyburns.com/Mitsubish...-Light-Fix.pdf
http://hdtvoice.com/voice/showthread.php?t=32186

Refer to the recommended parts distrubutors in the Manufacturer and Vendor Reference Information thread for suppliers for the caps. I highly recommend B&D Electronics for high quality parts and a good selection of caps. They will be happy to discuss the best caps for the application.