Step 1:
i had same problem with my magaworks 5.1 thx550.
i have tried to find solution in web but it was only one which voltage sense resistor 2Mohm track in PCboard was damaged.
after check PCboard in my megaworks thx 550 i found that tracks are quite well and voltage sense resistor is well too.Step 2:
REPAIRING PROCEDUREin below items there are repairing procedures that i did with my THX550.to access to BCboards it is required to remove electronic boards from woofer case.
1- remove cover of woofer.2- remove woofer speaker from case by cutting and marking connected wires.
3- remove all Philips screws around cover and remove electronic parts smoothly, care about glues around power cord.4- remove and disconnect power supply board from other parts.
5- replaced switcher TOP234Y and capacitors C102, C206, C205 and D10 as below photos.
7- now it is time to re assemble electronic parts very carefully and prepare for test. it is better to use isolated transformer and put a lamp in serial to protect PCboard against short circuit. if green LED (POWER LED) is on it means that every thing is O.K.
8- in this step all of electronic parts should remy megaworks 5.1 550 gets - 3_12_2013_9_02_39_am.jpgconnect sub woofer connections.
Step 3:
after replacing damaged parts my THX 550 is working well maybe for next 10 years.
i hope above mentioned instruction can be useful and helpful.
I found the same problem in my THX250D unit. Main fuse was burnt and the track for 2.2M resistor was broken under the main cap. The track was destroyed by arcs between main power rails! I saw some of them when powering the unit.
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SOURCE: Megaworks THX 550 does not power up
I was able to repair my sytem using the guidelines from pouakai at (http://forums.creative.com/t5/Speaker-Systems/Successful-repair-of-MegaWorks-THX550-power-supply/m-p... My system also would not turn on. The problem was on the power PCB - the one with the two large heat sinks attached. I found that the piece of PCB track joining the 2M ohm resistor (connected to the LINE-SENSE pin of the TOP243Y switcher) to the positive output of the full-wave bridge rectifier, was broken. This could have been caused by corrosion from the glue (which covered that section of track). I also replaced the 2M (0,5W) ohm resistor, just incase it was also to blame. The 2M ohm resistor is located under one of the two black heatsinks. I used a short piece of wire to replace the PCB track (from the large filter capacitor next to the resistor) to the 2M ohm resistor. Plugged everything back in, and it worked! The circuit diagram given on page 21 of the TOP234Y's data sheet was very useful, and helped me understand how the circuit functioned. I hope this is heplful for others who have this "no power" problem!
SOURCE: No power up on my
@bronk50 He said "No power up"... Useless reply !
I too have a Megaworks system and sometime after it has lost current for an extended period, it won't power up... but it does magically after some minutes. I don't remember exacty what I did last time it did start up, but it eventually got on !! My advice:
Let the sub plugged to the wall. Put the rear switch to OFF then wait 30 minutes. If it does not start up after that, let the switch ON and cycle ON/OFF after another 30 minutes.
Hope this helps! This system is underestimated... The subwooofer is so musical. Great bass comes from this system. Another hint: Keep your bass volume at 2 bars, I found it to be the sweet spot before it goes boomy :-)
I was able to repair my sytem using the guidelines from pouakai at (http://forums.creative.com/t5/Speaker-Systems/Successful-repair-of-MegaWorks-THX550-power-supply/m-p...
My system also would not turn on. The problem was on the power PCB - the one with the two large heat sinks attached. I found that the piece of PCB track joining the 2M ohm resistor (connected to the LINE-SENSE pin of the TOP243Y switcher) to the positive output of the full-wave bridge rectifier, was broken. This could have been caused by corrosion from the glue (which covered that section of track). I also replaced the 2M (0,5W) ohm resistor, just incase it was also to blame. The 2M ohm resistor is located under one of the two black heatsinks. I used a short piece of wire to replace the PCB track (from the large filter capacitor next to the resistor) to the 2M ohm resistor. Plugged everything back in, and it worked!
The circuit diagram given on page 21 of the TOP234Y's data sheet was very useful, and helped me understand how the circuit functioned.
I hope this is heplful for others who have this "no power" problem!
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how old are they? have you checked the plug fuse!
they are 4 years old. I checked the fuse, it seems ok... I am still looking for someone who can repair this...
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