Sanyo 46", Model DP46840, Manufactured: July 2010.
This post provides information in hopes it may help someone else.
A friend of a friend brought this set to me. It would not power up. It would attempt to come on and the power relay would click and the green power-on LED would light, but after a few seconds, the set would shut down & the relay would click off. Research on the Internet came up empty. Lots of people had this same problem, but no one posted a fix.
My usual troubleshooting failed to find the cause of why the set was going into shut down mode. Was able to find a service manual online for $15 and the owner bought it for me.
I found a missing +13vdc power source in the audio amplifier section. There is a switching regulator there that takes in +24vdc and outputs +13vdc. This regulator (IC1670) and the audio amplifier (IC001) are tiny surface mount devices. I wasn't sure if the regulator was bad....or if the audio amplifier was bad and loading down the regulator. I had to cut the tiny printed circuit board copper trace to isolate the 2 circuits.
That determined that the regulator (IC1670 p/n QXXGA0500165P or LV5806MX-TLM-H) was bad since it had +24v input and 0v output. Well, I could not locate that IC chip anywhere...Nobody sells it.
I could buy a whole new Main circuit board (1LG4B10Y04600_B) for $150 to fix this $600 set, but I wanted to fix it cheap.
So...I substituted in a standard linear regulator from my junk box that I had on hand: LM7815 (+15vdc regulator). I mounted it onto a heatsink, then mounted that onto a plastic crossmember and wired it into the circuit. Yes....I had to isolate the old regulator by cutting some more traces.
Set works great, the regulator only gets warm. I ran it for 10 hours for a burn-in test at a fairly high volume level.
Note: Circuitry is also applicable to the 42" Sanyo, model DP42840.
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