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Sharp 32" Aquos TV No Power


trailmug

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Paying a visit to the bus for some maintenance and thought I would post my experiences with the Sharp Aquos TV in the bedroom in our sig. It's an old 720p LCD, but the cabinetry is nicely built around the exact shape of that television, and I was finding it difficult to find a TV that would even fit in the hole, if I even wanted to try to fashion up some trim. I'm not much for woodworking, so I figured I would go for broke and try to fix it.

It works out that there's a common failure in the Delta power supply board used in these. It uses a single zener diode as a snubber for the standby power supply transformer, which is prone to failing short. The part number on the PCB is D7907. I replaced this once only to have it fail again. Maybe it doesn't like eating the stepped sine wave of the inverter, who knows.. The reference design for the SMPS IC is to use an RC snubber, and the board had solder pads for the passive parts, so I soldered them in. It's been working nicely for a year and a half. Here's the replacement parts list, and a photo of the repair, in case anyone ends up wanting to tackle the same issue.. not a bad deal for less than $1 in parts. 😁

R7917 and R7918: 200kOhm 1/8 watt
C7913: 2200pF 1kV Vishay Series F, PN: F222K53Y5RN63K7R
D7907: remove

If memory serves, this power supply has a "hot chassis," so keep your hands to yourself if you have it plugged in with the case off.

20210701_144435.jpg

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You certainly know your way around chasing electrons….LOL.  I thought you had a PURE sine wave Magnum maybe the PS2812.

I will have to check our Camelot build for the model number.  I have fixed a few LCD flat screens by the capacitor replacement kits that are on eBay….maybe now on Amazon.

Thanks for the tip.

If you have time, could you take your post and pictures and write up a simple HOW TO White paper and PM to @Frank McElroy  He is the czar of files and we have a lot of “HOW I FIXED THIS” files.

Great job.

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It's an original Magnum PS, yeah.. I hooked up a scope to it one time because I was curious, and the quality of the waveform seems to vary a lot with load. I think it would take a pretty expensive filter to smooth out the steps from the FETs.. or mine is just old and has dried up capacitors. For the sake of novel discussion, I did place a car audio 1 farad capacitor across its input with some heavy wire to see if I could cut down on the light dimmers flickering while running the microwave on battery (which I wouldn't generally recommend, but I try not to start up the genset to nuke a hot dog or make a pot of coffee 🙂 ). It helped some, but I'm glad I used heavy wire.. if memory serves, ripple current was as much as 60A. 😮

I wish RV manufacturers used 24V house electrical systems.. It would cut down on a lot of silliness.

invcap.JPG

Edited by trailmug
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You’re better than me. I was trying to get mine to work last week. Previous Owner had disconnected everything and I finally got it rewired where the DVD player works but I still can not get any reception on a TV portion. It can’t find any channels. I even bought a new over the air antenna but nothing. We don’t watch much TV so the DVD should be good for a while. 

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Digital TV reception is a pain in the rear.. I think I'd need a toner if I was going to try to hook up the coax to the roof antenna (which has a stripped motor anyway). It's impossible to get a good "set-top" HDTV antenna, I live 6 miles from the antenna farm and I still need a Channel Master in the attic!

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1 hour ago, trailmug said:

Digital TV reception is a pain in the rear.. I think I'd need a toner if I was going to try to hook up the coax to the roof antenna (which has a stripped motor anyway). It's impossible to get a good "set-top" HDTV antenna, I live 6 miles from the antenna farm and I still need a Channel Master in the attic!

Both in our old and new house we rely on OTA antenna for TV reception, we cut the cord when we moved so no phone or cable. 

Have an ATT $24/month hot spot and a antenna in the attic similar to this https://www.lowes.com/pd/GE-Yagi-Outdoor-HD-UHF-VHF-TV-Antenna/1001330804. 

We have a 2 story house and it is high in the attic and get ~70 channels, we live ~25 miles east of Knoxville.  I have a similar antenna mounted on the garage at a lower elevation and get ~40 channels. 

When we lived in our old house I played with a bunch of different antennas for the house and none got as good of reception as the good as reception as the Wingman on the motorhome even though it was parked at a lower elevation with the house generally obstruction the direction most of the signals came from.  The best antenna I found was an small RCA outdoor that I could mount on a pole but at some point it broke, I replaced it with a King jack type but it didn't compare. 

I even tried the type that you can put in a window, it was very dependent on line of sight reception.

One thing you might try is putting another amplifier on the bedroom TV.   I have two amplifiers in our house.  One amplifier is right at the antenna and feeds channels on the upstairs and kitchen area.  The rest of the TV's are fed through a second amplifier which helps the signal.  Not sure if putting two amplifiers in series is recommended but it seems to work for me. 

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This may be somewhat relevant to the part about getting signal to the bedroom.
I previously struggled with wireless HDMI extenders to get Direct Tv and Dish signal from the box in front. The wireless extenders worked but were sensitive to RF interference, especially around airports. 
so I tried HDMI over Cat5e. I was able to snake a cable from the driver’s side pillar to the rear cavity behind the electrical panels. Then ran it behind covers along the back of the coach and into the bundle that feeds the curbside bedroom slide, and up the outside slide wall to the tv cabinet.

The curved section along the top of the outside walls where the roof meets the upper mold line is hollow and has existing wiring in it. To avoid snagging clamps, etc, I used a wire pulling set called “Magnepull”. It uses a strong roller magnet and matching magnetic torpedo to enable pulling wires through hidden spaces. This allowed me to pull 2 strands of Cat5e (one for spare/futures) along the top of the curved section to avoid snagging. It worked well. So does the HDMI extender. If I were to do it over I would probably upgrade to Cat6 shielded to potentially improve signal quality and limit potential A/C interference. There appears to be some romex cable also running down this channel. 
I hope this helps someone wanting to get wires from the front to back.

Roy

PS: I also used this method to pull a wire for my Winegard Connect 2.0 from the refer vent to the front audio cabinet. But for this I had to drill a hole from the vent framing through the outer roof framing. These pieces of framing are separated by about 3/4” or so. Overall, not too difficult.

 

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I have a Sharp AQUOS model TU-GA1U-S Receiver/tuner that I removed from my 05 Executive when the TV crapped out. It was working when I removed it. the remote and all the wiring goes with it.

I also have the speakers that were attached to the TV.

If anyone is interested it yours if you pay for the shipping.

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  • 2 weeks later...
On 2/8/2023 at 9:16 AM, RIPPPA said:

You’re better than me. I was trying to get mine to work last week. Previous Owner had disconnected everything and I finally got it rewired where the DVD player works but I still can not get any reception on a TV portion. It can’t find any channels. I even bought a new over the air antenna but nothing. We don’t watch much TV so the DVD should be good for a while. 

Fwiw, I struggled with the same thing, I replaced the original tv antenna with a new King Jack digital antenna and mounting plate, still no OTA television. On a trip to Best Buy I talked to a young man in the television sales area, he suggested that I try a digital to analog converter box because of the age of the tv’s, after a bit of plugging wires in and out and experimenting I have tv, and using the Sony Theater in a box with all of the speakers in our coach I must say it’s actually quite nice! I’m not particularly interested in replacing all of my tv’s at this point, I’m sure it will happen but I do like the fact that they fit the cabinetry! 
 

9D75AC5D-386B-4051-B4DD-5FA3B4C4C609.jpeg

326A7690-0A20-485E-9CFB-241295561263.jpeg

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I have the Sharp Aquos AVC ModelTU-GA1U-S that is identical to the one in the picture. I removed it from my 05 Exec when the TVScreen went dark and I upgraded to a Smart TV. I have the remote and Cables. The unit was working when removed. Anyone interested can have it, just pay for shipping.

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