Acoustic solutions LCD26761HDF no backlight

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Too bad you DID NOT tell us that you did not check to see if it is putting out the 24vdc after the IC is replaced! I am begining to wonder if you do have the 24vdc all along but the problem was a blown fuse for the Inverter controller circuits.
That is OK, now you know a lot more than before! I am just glad to be able to do remote troubleshooting.
Cheers!

When i first got this set there was no 24v reading at the inverter pin out on psu..with or without inverter lead pluged in..so that IC must have been bad & needed replacing as well as the fuse...was so close to throwing towel in & telling my m8 that he needs another psu..total cost should be 5pounds with the fuses added..so once again you guys you guys fixed this set i was the 1 sh**ing it with multimeter..lol

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Too bad you DID NOT tell us that you did not check to see if it is putting out the 24vdc after the IC is replaced! I am begining to wonder if you do have the 24vdc all along but the problem was a blown fuse for the Inverter controller circuits.
That is OK, now you know a lot more than before! I am just glad to be able to do remote troubleshooting.
Cheers!

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

I jumped it for now as ive no fuses etc
http://i1068.photobucket.com/albums/...5/P1000929.jpg
And its working...thx for being very patient with me..im a very very slow learner lol...if you guys lived near by it would be beers all around..im gonna get them fuses from selldoors link tommoz...so TOM..BUDM..SELLDOOR&again..thx

As the PSU puts out about 4A remember to replace it sooner or later or you will have a mess of melted wire to fix if something goes wrong.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Put 2.2 Ohm in place of the fuse for now.

I jumped it for now as ive no fuses etc
http://i1068.photobucket.com/albums/...5/P1000929.jpg
And its working...thx for being very patient with me..im a very very slow learner lol...if you guys lived near by it would be beers all around..im gonna get them fuses from selldoors link tommoz...so TOM..BUDM..SELLDOOR&again..thx

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Put 2.2 Ohm in place of the fuse for now.

[selldoor]

Re: Acoustic solutions LCD26761HDF no backlight

I think he said 2.2 ohm not kilo ohm

They are very small - see http://cpc.farnell.com/phoenix-passi...70?Ntt=re03770

or These for the 2.2

http://cpc.farnell.com/phoenix-passi...71?Ntt=re03771

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Disregard the R925, that message was for another person in another thread, sorry, too many threads to reply to.

So that 2.2k is ok to test for know fella..thx

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Disregard the R925, that message was for another person in another thread, sorry, too many threads to reply to.

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

What I mean is that you can use small value resistor in place of the fuse. Sometime it is referred to fusible resistor, very common usage in place of the fuse.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Sorry, R925.

3 reds & gold is 2.2k correct...the R925 is that a common part..thx
Found a red red red gold gonna desolder & get bk to you guys...thx

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Sorry, R925.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

At this point, since the PFC is working, then I would say the PS_ON is OK since the 400vdc is now feeding the 24vdc switching power supply circuits, that 1A fuse on the inverter board is for the controlling the Inverter circuits which turns on/off the Inverter Oscillator/output driving/Dimming circuits.
I use Littlefuse PICOFUSE 1A in its place. You can use 1 or 2.2 Ohm 1/4W MOX resistor for now to test.

Budm sorry for not knowing which resistor you mean..dont suppose you know what colour bands are so i can look on some old boards..thx

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

At this point, since the PFC is working, then I would say the PS_ON is OK since the 400vdc is now feeding the 24vdc switching power supply circuits, that 1A fuse on the inverter board is for the controlling the Inverter circuits which turns on/off the Inverter Oscillator/output driving/Dimming circuits.
I use Littlefuse PICOFUSE 1A in its place. You can use 1 or 2.2 Ohm 1/4W MOX resistor for now to test.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Different approach-

I'm guessing you have standby voltages?

Is there an on/off signal going to be the PSU to turn the 24V on or off?

Is that the 12pin of PL802 tom..thx

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Tom how am i checking your sujestion..thx

Can you plz tell me what to check on the schematics..thx

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Different approach-

I'm guessing you have standby voltages?

Is there an on/off signal going to be the PSU to turn the 24V on or off?

Tom how am i checking your sujestion..thx

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

Different approach-

I'm guessing you have standby voltages?

Is there an on/off signal going to be the PSU to turn the 24V on or off?

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

That is 1A fuse as printed on the circuit board, where is this fuse at again? I thought you had checked to see if you are getting the 24vdc OUTPUT after installed the new IC!

No m8 i never checked for 24v after installing new IC..the fuse is on the inverter board..its F1A/76v not 75...should i jump it for now with solder wire till i get a new fuse..what type fuse should i get..thx
I checked google for the type of fuse & came across this
https://www.badcaps.net/forum/showth...18526...should i try the same procedure..thx

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

That is 1A fuse as printed on the circuit board, where is this fuse at again? I thought you had checked to see if you are getting the 24vdc OUTPUT after installed the new IC!

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

So that signal is the Positive, which is fed into the base in one of the two transistors in that section. We need to draw out how those two transistors and resistors are connected to pin 2 and pin 3 of the IC. That voltage must be used to turn on-off the Oscillator circuits of the PFC IC, that is the only thing I can think of.
Can you draw out the physical connections of that section, or the schematic of it?

Budm while doing them last measurements id thought id check the 24v pin out since ive not checked that since IC fitted..all 4 red wires measure 24v..so i took the shield off & found another fuse F1A/75V which seems to be shorted as no continuity..its got 20 as markings only..thx
http://i1068.photobucket.com/albums/...5/P1000915.jpg