Help with Hitachi TV power supply board repair

[Navagator]

I have an older Hitachi Rear Projection TV that still works great or I should say did work great until 3 or 4 days ago. I came in and tried to turn it on and it was just dead. So, I unplugged it and plugged it back in. Nothing, not even the slight click that it makes when you plug it in. So, I removed the power supply board and inspected it visually for bulged caps or burnt spots, anything that didn't look right and couldn't find anything.

I noticed on the bottom of the board there was a row of solder joints with voltages printed next to them(10.5v, Gnd, Gnd, 5.6v, 5.6v, Gnd, 16.5v, Audio Gnd, Audio), which are coming from the large transformer on top. I checked all of these voltages and they're all reading between 12.5 to 12.7 volts except for the 16.5v joint and it's reading .6 volts. I'm not an electronics technician but I assume this isn't right.

I would really appreciate any help anyone could give me in fixing this issue. It's an old TV but it shill has a great picture an I would prefer to fix it if I can. As I said I'm not an electronics technician but I can desolder/solder components, so if I could just figure out which one/s are bad I might be able to fix it.

Thanks in advance.

 

[Tony Stewart]

The problem could be upstream of the 16V or a short downstream, but unless you know how to isolate which way to go by disconnecting the output, it's like trying to teach someone how to fly an airplane in the air in real time and the stall indicator comes on.

But check upstream 1st after you find a schematic.

 

[Lightium]

Did you look for a fuse?

 

[Navagator]

The problem could be upstream of the 16V or a short downstream, but unless you know how to isolate which way to go by disconnecting the output, it's like trying to teach someone how to fly an airplane in the air in real time and the stall indicator comes on.

But check upstream 1st after you find a schematic.

Thank you for your reply. I'm afraid that's a little more than I can handle.

I had a chance to buy another set just like mine a few months back for 50 bucks but didn't, now I wish I had.

 

[Navagator]

Did you look for a fuse?

Yes, there is 3 fuses. They all look to be in tact.

 

[Lightium]

I suggest you find a reputable repair technician in your area. What's the model of the projector?

 

[Nigel Goodwin]

I suggest you find a reputable repair technician in your area. What's the model of the projector?

Or even better replace it with a decent LCD TV, rear projection sets never gave particularly good pictures when new, and they age particularly poorly as well.

Luckily they are long since gone now

On a positive note, such as it is, they are relatively light for their screen size!.

 

[Navagator]

I suggest you find a reputable repair technician in your area. What's the model of the projector?

It's a 57F710E.

 

[Tony Stewart]

Sadly, they don't allow picking apart scrapped electronics in the trash depots in Toronto where you might find plenty of rear projection TV's but you often see them left at the end of the driveway for free pick-up.

I liked the effect of the transparent mirror glass when I picked that from one for my tool shed. The tree reflection made the illusion of seeing thru the building.

 

[tepalia02]

Do not forget to perform a short circuit test on the board.

 

[Nigel Goodwin]

Do not forget to perform a short circuit test on the board.

Is that supposed to mean anything?.

 

[Doug]

I don't see a post from the transformer on the 16.5.. maybe a chassis version that didn't use 16.5 from the transformer

 

[Navagator]

I don't see a post from the transformer on the 16.5.. maybe a chassis version that didn't use 16.5 from the transformer

Yes, the 16.5v connection isn't hooked up to the transformer. I overlooked that.