hitachi l40c205

[lrr250r]

Hello all have a non working hitachi l40c205 that someone was throwning out. Tv originally didn't power on at all. Upon inspecting the power supply(rsag7.820.1673/roh ver f) I found that the glass fuse was blown and the triac at v811 cracked. When I replaced the fuse and plugged cord in v811 threw sparks and the fuse blew again. I picked up what i was told was a re-manufactured power supply off ebay. Now when i plug it in i hear one click(sounds like its coming from power supply). The red power light comes on however the set doesn't power on. I don't have the remote for the set and the power button is the touch setup. Is there a way to turn set on via jumping any connections. Any tests st this point would be helpful before i place it back out on curb... thanks

[drpj23]

Re: hitachi l40c205

Could you include pics of the power supply and of the outputs using the manage attachments feature, please?

[lrr250r]

Re: hitachi l40c205

you want pics of the orig as well as the so called reman ?

[drpj23]

Re: hitachi l40c205

Sure, am interested to see the cracked component.

[lrr250r]

Re: hitachi l40c205

old board

[lrr250r]

Re: hitachi l40c205

here is the new board......i did notice that c842 on the new board is blue and doesn't look right to me....its black on the old board.

[drpj23]

Re: hitachi l40c205

Wow, it looks like it cracked that green varistor.....wonder what caused all that

Anyways, on the power supply, what are the voltages.

Now, just to clarify, with the new p/s, it has a red standby light but that's it? Power button does nothing at all? or does it go to a red light?

That blue cap looks like a plastic film type; it should be fine.

[lrr250r]

Re: hitachi l40c205

As soon as it's plugged in the light on front comes on red. I do not have the remote for the tv and all the controls on the set are touch. When i touch where it says power nothing happens at all. I tried programming a few universal remotes with no luck. I'm not sure if the problem is in the power supply or the controls. Can you walk me threw where to test for voltages on the power supply?

[lrr250r]

Re: hitachi l40c205

I see some voltage values silkscreened at the connectors.....is that where i should test or are there specific componets you want values on?

[drpj23]

Re: hitachi l40c205

You should have a standby voltage of about 5v on one of those connectors.....but include a pic of the printed legends.

This is sounding like a main board fault since that cuts on the p/s to provide power to the rest of the boards.

[lrr250r]

Re: hitachi l40c205

5v_s 4.77 volts
5v_s 4.88 volts
both 12v pins as well as both both 5v_m pins show no voltage


this is the 14 pins connector from power supply to the main board

[lrr250r]

Re: hitachi l40c205

meter shows no voltage at any of these pins. should be 24,16 and 5 volt values in various pins. all metering done with plugs removed from sockets on power supply.i also don't see any voltage on either side of the glass fuse.

[lrr250r]

Re: hitachi l40c205

wonder if i can remove cracked parts from old board and replace with ones from this board

[drpj23]

Re: hitachi l40c205

Ok that is good. You will not have any other voltages since the power supply is in standby.

Your glass fuse is good since you are getting the 5v and has AC not DC going across it.

And lastly I would not replace parts from the "new" board. Buy parts from a place like digikey so you are not stuck with two non-functional power supplies.

I'll do some research later on that power supply but budm or tom66 can help you faster than I can research. I am very tired lol

Oh I do suspect a prob with main so could you please include pics of it.

[tom66]

Re: hitachi l40c205

You want to check SW. If it is changing when the power button is pressed, but the voltages aren't coming up, it points to a power supply problem. If it's not changing, then it points to a main board problem.

[vinceroger69]

Re: hitachi l40c205

meter shows no voltage at any of these pins. should be 24,16 and 5 volt values in various pins. all metering done with plugs removed from sockets on power supply.i also don't see any voltage on either side of the glass fuse.

it might be worth rechecking for the missing voltages with the plugs connected to the sockets on the power supply.
you should be able to use one of the mounting screws as a earth for your meter then test from the top of the connectors just push the red lead in untill it makes contact then note each reading.

[lrr250r]

Re: hitachi l40c205

Ill check the voltage while hitting the power button as well as with all connectors plugged in. This set has touch controls on the front. Is there a method of jumping points on that board or main board to see if issue is with board....wish it was standarnd tactile buttons.

[lrr250r]

Re: hitachi l40c205

Here are some main board pics......ill pull it later and inspect

[lrr250r]

Re: hitachi l40c205

tom66 what is SW and where would i check it ?

[tom66]

Re: hitachi l40c205

It's on the PSU, pin marked SW. Likely the on/off control.

You may be able to locate the connector for those buttons and find the pins that correspond to the power button, then jumper those to send the signal to the TV.