Toshiba LCD 26AV502R - no picture but I do have sound

[vinceroger69]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

now, on the inverter board, check the dc voltage on each side of the fuse f2 and report back. make sure it is resecured prior to applying power. cover can stay off.

Answer: F2 appears to be a surface mount fuse such that it cannot be removed without desoldering. When power applied, I get 0.000VDC across it.

in a dark room, is there a small splash of backlights on start up?

Answer: No, I don't notice a splash on start up.

can you re tsest the fuse black probe on tv metal chassis then red lead test on each side of the fuse its usually 12v or 5v

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Oh duh I feel like an idiot. Sure. I'll measure it and post back in about 4.5 hours (when I get home).

Thanks all!
VV5

[budm]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Check very small black F1 fuse (see picture for example to see what the fuse look like) with '20' printed on top, it is below the printed 'CMO' silkscreen. More likely that fuse had failed, very common on CMO inverter board., It should have 24VDC at both ends with ref. to the chassis GND.

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Fuse F2 shows 24.22 Volts on either side. Fuse F1 shows 0.003 V.

So is this the culprit?

[budm]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Yep. There is print right next to it beside F2, it shows current and Voltage rating of that fuse. I believe it is 1A fuse.
This looks to be your board:
CMO 27-D023043 (VIT70063.50)
http://www.shopjimmy.com/cmo-vit7006...t-inverter.htm

BTW, "Fuse F1 shows 0.003 V." Do you mean one side shows 24V and another side shows 0V?

[diif]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

F2 is the fuse for the inverter board. When you tested did you have the black lead on an earth with the red lead on either side ? Does the multimeter have a continuity mode ? You can test the fuse with that.

I should refresh the page before posting on my mobile. Lol.

[budm]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Yep. There is print right next to it beside F2, it shows current and Voltage rating of that fuse. I believe it is 1A fuse.
This looks to be your board:
CMO 27-D023043 (VIT70063.50)
http://www.shopjimmy.com/cmo-vit7006...t-inverter.htm

BTW, "Fuse F1 shows 0.003 V." Do you mean one side shows 24V and another side shows 0V?

Correction, I mean F1 black fuse.

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

diif,

When I tested F2, the black lead was on earth and I received 24.22 V on both sides of the fuse. Is this normal?

budm,

Similar to my response to diif, I received 0.003V on both sides of the fuse when the black lead was on earth. Apologies for not being clear.

So F2 is good? F1 is shot? What next?

[vinceroger69]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

f2 fuse is good maybe check f1 fuse in diode mode with your mutimeter (test straight across the fuse as meter is in diode mode with NO power too tv) if fuse tests good we need too see why voltage isnt getting to that fuse,

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

F2 is good with continuity. F1 is not. I did the diode test on F1, without power, and showed that it was not open.

So I believe F1 is the culprit. What are my options?

Thanks!

[dskall]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

So do you get voltage on both sides of F1. It can't be good and bad

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Maybe I have my terminology mixed up. Sorry.

When I tested F1 with the black lead on ground, there was hardly any voltage on either side (0.003 VDC). This was with the TV powered on.

With the TV powered off, I put it in continuity, and there wasn't a continuity beep coming from the meter like F2. I think we can rule out F2 at this point.

Now, the diode test for F1 - pardon but I'm not that familiar with how the diode test works (like the results), so I noticed when I put both leads on F1 in diode test mode without the power on, I saw the VDC level increase to about 1.63 V.

Did I do something wrong?

Thanks.

[dskall]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

So you are getting 24v both sides of F2 but no voltage on either side of F1 correct. If that the case it looks like F1 is feed off of F2 so there must be a break in the trace between them. With power off do you have continuity between F1 and F2?

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

dskall,

I am getting voltage on both sides of F2 but nothing on F1 - correct.

Quick question, how would I test for continuity between F1 and F2?

[budm]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Just put the meter in 200 Ohm range, then one probe probe of the meter to either end of F2 leg, another probe top the top end of the F1 fuse, it should show <1 Ohm depends on your meter probes resistance.

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

All,

There's only one side of continuity between F2 and F1.

Here's what I did for measurements. I called them left and right.

Left Side F2 to Right Side F1: 0.3 Ohms
Right Side F2 to Right Side F1: 0.3 Ohms

Then,

Left Side F2 to Left Side F1: 62.3 kOhms
Right Side F2 to Left Side F1: 62.6 kOhms

So, I believe F1 is bad, but does the "left" side of F1, being high resistance, indicate a problem in the trace?

Thanks!
VV5

[dskall]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

From your inverter picture you are sure you are getting voltage on top end of F2 white fuse and no voltage on top end of F1

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Here's what I did.

Black lead on ground, red lead checking fuses.

Results are as follows:

F2 Fuse, left side = 24.22 VDC
F2 Fuse, right side = 24.22 VDC

F1 Fuse, left side = 0.08 VDC
F1 Fuse, right side = 24.22 VDC

Sorry of the "left" and "right" are confusing. Just makes it easier in my head.

[budm]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

Here's what I did.

Black lead on ground, red lead checking fuses.

Results are as follows:

F2 Fuse, left side = 24.22 VDC
F2 Fuse, right side = 24.22 VDC

F1 Fuse, left side = 0.08 VDC
F1 Fuse, right side = 24.22 VDC

Sorry of the "left" and "right" are confusing. Just makes it easier in my head.

OK, now you telling us you do HAVE 24VDC on one end of F1 fuse? I thought you told us you do not have any Voltage (0.003v on either end of F1 fuse at all. Just change that F1 fuse and finish with the repair, the thread is getting too long for a simple fuse.

[VictorVictor5]

Re: Toshiba LCD 26AV502R - no picture but I do have sound

budm,

Apologies - that fuse is really small so I had to use some force on the probe to get a reading. But I can confirm that I get one side voltage, the other side I do not.

So what does this mean?