www.my.electronicshelponline.com/uploads/V26_Service_Manual.pdf
Above is your service and repair manual, below is your user manual.
http://www.retrevo.com/support/Mitsubishi-WD-52825-TVs-manual/id/276ag911/t/2/
Those symptoms you describe, prior the "Reset Button" incident, indicate a fault in the Horizontal section, either a fault in that actual section or the Voltage from the SMPSU, is failed or missing, as usual though one always starts at the SMPSU, and check the voltages are all correct as if they aren't correct here, then no where else can be OK. If you wish to DIY, then these manuals above will be invaluable.
This maybe a classic switchmode power supply problem, there is protection circuitry built in, to detect faults, and there is a "Protection mechanism" which is shutting down the set to avoid a fire, explosion, or both. This set has developed a problem, that is so severe that the set must be shut down, This set should now, be removed from the Power, and in my professional recommendation, you should get a "Quote" for repair, from, an, Approved Service Center, this point is very important for a good result, Always contact, their local, "Head Office" M
itsubish, in your case. Now, when you get the information you want, from the "Quote" well, then you can decide as to repair of replacement. The reason we want an approved agent, is that way, all the engineers are trained on their own brand sets, they have seen almost all faults, and will get the job done quicker, and for less cost, and usually have original parts on hand, also sometimes, there has been a service bulletin in issued and the repair may be subsided or even free.
