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Discussion Starter #1
I have a Hitachi 57f710s manufactured in May 2005 that made a loud pop and stopped showing video. It still makes the clicking noise when you push the power button on and off, but it doesn't come on. The front red power led doesn't light up and the two green led's on the power board don't light up either. The 160v capacitor next to the flyback transformer is slightly bowed out, but not enough to have made the loud pop. The 3 fuses in the area seem fine. What's the most likely problem?
The only manual I can find is for the 57f710a, is that good enough?
Thanks.
 

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The manual is likely close, but you need to get the entire manual for that chassis series to be sure what the differences are. Your cap likely vented, a related cap blew, or the flyback blew. If you do not have the proper equipment and skill to troubleshoot a deflection and flyback circuit I recommend that you contact a professional for an estimate. You might have something as simple as a cracked solder joint or you could have a defective component that might be hard to locate. Regardless, it is easy to make mistakes than can be dangerous or can create more problems in these circuits, like damaging the connections on the wires on the flyback transformer. Please be careful.

Check your fuses again, specify which circuits are not powering up (based upon which LEDs don't light up and measurements), test the flyback with either a low voltage drive test or ringing tester, and look for a burned cap.
 

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Discussion Starter #3
That was a quick reply! Thanks.
I found this post on AVSforum:
BTW: Just to clarify for all of you that were wondering about the "S" and the "A" at the end of the model number.........It has nothing to do with color of the TV itself..........The F710S has two NTSC tuners for complete PIP, plus an ATSC tuner for the HD content. The F710A has only ONE NTSC tuner, plus the ATSC tuner for HD content.

With the F710S, you can either watch two SD channels at once or one SD and one HD channels at once, but not two HD channels at once.

With the F710A, you can only watch one SD and one HD channel at once. You cannot watch two SD channels at once, nor can you watch two HD channels at once.

As for the "A" and the "S", the only other difference I found is that the "S" has a RS-232C Control Interface (what ever the hell that is, I've never heard of it) and the "A" does not.

Also, the FULL SPECS sheet lists the "S" as Energy Star Compliant, but the "A" does not. This is not true, because my model is the F710A and it has the Energy Star logo on the front, and I believe it says it in the manual as well. Just wanted to let you all know what I found.
So it looks like the manaul for A should be fine. I would at least want to replace the bulged capacitor to see if that's the only problem before calling a professional. All fuses are good.
 

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Discussion Starter #4
I can't find an exact match for the capacitor. It's 160v 680uF 1 3/4" x 7/8" (22mmx44mm) 105°C. I can find a match on eBay that's 85°C. Otherwise the closest I can find is a 250v 680uF 105°C at bgmicro, or a 200v 680uF at alltronics that doesn't have a temp rating. Would either of these work?
 

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I can't find an exact match for the capacitor. It's 160v 680uF 1 3/4" x 7/8" (22mmx44mm) 105°C. I can find a match on eBay that's 85°C. Otherwise the closest I can find is a 250v 680uF 105°C at bgmicro, or a 200v 680uF at alltronics that doesn't have a temp rating. Would either of these work?
No problem in most cases going up on the voltage rating on a cap. The only caveat is that all else being equal, a higher voltage rating usually comes with a higher impedance, which can matter in some cases. The reality is that all else is rarely equal and you may not be able to tell what the original cap impedance was to start with. Chances are it was cheap or defective anyway. Just get the lowest impedance, longest life cap you can find in the same capacitance that will fit. Digi-key is hard to beat for selection and the Panasonic and Sanyo caps are usually among the best, IME.
 

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Discussion Starter #9
I see. I filtered by 22mm(the one you listed is 25). There's only 1 option that doesn't require a $500+ minimum for that size.
 

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they probably don't stock the 22 so they would have to order a ton just to get them. You should be able to go up in height 3 mm unless it sits under something really close to it.
 

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Discussion Starter #11
After replacing the capacitor, the two green led's light up for a second, then slowly die out. So, the cap was bad, but that still didn't solve the problem. The expert here says replacing the power supply board should fix the problem. There are 2 options on the website for this board, one is $32, and one is $96. What's the difference; should I just get the cheaper one?
Thanks.
 

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We don't have enough information to conclude anything. I would not trust a diagnosis from such "experts." They rely primarily on symptom repair databases and guesses. I would be doing more troubleshooting to isolate the problem. As for the difference in the boards, I would ask the vendor. Probably a rebuilt or salvage board at that price, but maybe Hitachi reduced the price?
 

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I am not a TV technician although at one time years ago with different circuitry I ran a service center for a national chain. My instinct, and it is only instinct, is that the power came up and as it did so a protection circuit kicked in and shut things down due to something still being wrong. I would look closely at resistors near that cap to see if any show unusual darkening or discoloration and if so measure it (them). I would also look for threads in forums related to that cap to see if anyone else has repaired the same issue and what else they found. With luck and God on your side you may find someone has been thru it before and solved it. The reason, and again it is only instinct and nothing more, that I think it may be a protection circuit protecting the TV is that the LEDs did turn green. That means that at minimum they did have the correct power to them to make them glow. At least part of the power supply is providing voltages within tolerance to make the LEDs glow. My guess is that something pulled excess current and the power supply down. Much more testing would have to be done by someone wiser than me.
 

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Hitachi's are pretty easy to troubleshoot, relatively speaking, because the LEDs tell you when a particular power supply is running. You have the additional clue of a swollen cap. The question I would be asking is why that cap failed. Did it just die itself and take something else out with it or dis some other failure cause excessive voltage or current at that cap. Either way, you have a good place to start, as the remaining problems likely include something in the circuits related to that cap.

Changing boards is a problematic technique itself. Techs that I know estimate about 20-30% of the boards they get are defective. There are several reasons for this. First, many parts are not factory new but salvages from set with other problems (presumably). Also, many people without good troubleshooting skills are swapping boards and returning them when they do not solve the problem. Vendors cannot test boards without a working set and this is not practical. Many of these boards are damaged in handling or have other problems introduced because some other problem exists in the broken set that damages the new board. Then there is simple dishonesty and sloppy business practice. It is a well known practice that people send an old defective board back reporting that they received a DOA part. The parts suppliers are left with the dilemma of restricting returns and losing customers, taking the chance on shipping the part to someone else, or very expensive quality control. You can guess what they always choose.
 

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Discussion Starter #15
Encompass Parts said the difference is that the part ending in R is a rebuilt part. So the cheaper part is actually the better part since it's not rebuilt? I've never seen new boards for $32 anywhere else.
 
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