Cross a sharp LCD TV with a BenQ, what would you get? (Part 3)
Continued
Below is a pic of the tube connection and powered up.
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2FBenQLampsExtended.jpg&hash=ddced584370919a011e70440f8a35f18)
Next was to mount the Inverter. Since the BenQ one was of low profile type, the sharp one will never fit the BenQ's inverter mounts. Again I have to compromise.
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2FBenQTVwithSharpInverter.jpg&hash=140322fb5705deab331d492119d23c46)
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2FBenQTVsharpinvertermount.jpg&hash=747dd9183813b09d796412f13f0b08c2)
I have to get rid off the BenQ speakers to mount the Inverter, Since the Tube connectors have HV Insulation and any longer wire than necessary will tend to generate a lot of EMI, second getting HV insulated wires is impossible here, and also the mechanical work associated in all these modification will cost a lot and will take a lot of time, this was the best option. Besides I never like the small speakers it has, and I have a 7.1 one custom built sound system with my HTPC, I do not need any more speakers. 😛. And my audio Rocks. hehehe!!
In the second picture u can see the plastic I used to insulate the inverter since I got electrocuted ones or twice without it. I'll say it was quite an experience touching the HV.
The plastic is quite nice isn't it, I have a cousin who is in business with laser cutting and engraving all kind of materials. The laser engraver is quite unique and one of a kind here, I can make any thing with it, and I am thinking of making bezel facia for this TV, with all the art works and stuff, but that will be a bit later.
The plastic provides a solid mount to the chassis.
The tube connections a kept to a minimum and has HV heat shrink tubing to prevent unnecessary arching to the chassis. Still I donno how long the insulation will hold, it is yet to be tested how long it will take the tubing to degrade.
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2FBenQReessembling.jpg&hash=61fb154c69f4f0247cf9c193ae328de2)
Finally Inverter Assembled
Next comes the PSU modification, but before that a lot of measurements were taken about the voltages and current ratings. I wasn't going to use both the supplies in it, no place to mount and it will generate too much heat and consume unnecessary power.
Initial testing was done without the inverter and with the benQ PSU to see how much power is consumed by the panel and the axillary circuits.
The BenQ Panel was using the LVDS signal and mainly the Auxillary supply like 3.3V, 2.5V and 1.2V that was neccessary for the panel and DSP is regulated by onboard switching regulators on the DSP Assy and all it needs was 12V @ 0.5A and a 5V at around 1.5A tops. The audio amp uses complementary 16V supply and the inverter is powered by a bulk 14V.
The switching voltage necessary to turn on the PSU from stand by and inverter is @ 3V. Plus a stand by 5V @ 0.5A.
Since I attended the sharp PSU before I was quite familiar with it's voltages. 400V DC to the Inverter, Complementary 14V to the audio, two 3.3V @ 1.5A, 6V @ 1.5A and a stand by of 3.3V.
So replacing the BenQ PSU with the sharp one is childs play. Only problem was the ever 5V needed by the BenQ DSP, and it will not operate if it drops even by 0.5V.
I have to use a seperate 5V PSU to oparate the BenQ DSP at stand by and modifiying the sharp ever 3.3V is really difficult since this ever 3.3V feed back loop is cuopled with the charge pump circuit in the sharp PSU, any change I brought to increase the 3.3V to 5V hinders with charge pump operation. And making a charge pump takes more time, and I was in such a hurry to get the TV in to my room 😛.
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F5VPSU.jpg&hash=fdbe0d77585c5a28bec19cd87cbc9f3b)
Here you can see a small 5V PSU I salvaged from my junk. suites well, doesn't it? Well that's settled.
Next was to modify the out puts of sharp PSU. A quick reference to the data sheets of the regulators used in the PSU secondary showed it's easy to generate at least 5V difference as long as the voltage does not go below it's rated output, since these were switched mode regulators. it was easy.
The 3.3V was not necessary, so it's regulators were omitted and the fault detecting circuits were bypassed for this output and the 6V feed back was increased to decrease the output to 5V. Since the sharp PSU and the benQ regulators were of type 1.5A current ratings, It was not necessary to even check if the supply could handle the current, something I learned over the years, Just by looking at the regulators, transformer, inductor and the caps I can assume it's power handling capacity. The Audio supply is OK since I don't need them but to test, and almost all audio amps can handle a change in plus minus 5V or so provided the out put level is kept low.
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2FBenQback.jpg&hash=1d789e8ed77b5af47c88d20b77121880)
Here is a pic of the benQ back before the removal of it's supply.
Now with ever 5V added, it was time to see if the BenQ processor worked switching it's control terminals. There was only one switched out to the PSU. All the rest are powered up when the supply switches on.
The Sharp Inverter has more terminals than I bargained for, at least seven, as a rule of thumb, there will be +Vcc, GND, fault feed back and the back lit brilliance control, still 3 is left and I have no idea what the heck those 3 does, so a quick fiddling was necessary. It seems that the control pin has two inputs which has a high input of 3.3V to be activated for the inverter to power up. The Inverter 400V DC is separate and is powered when the PSU switches on, so that was settled, now since I am using the sharp PSU, getting the supply for the low voltage side of the inverter was no problem, all I have to do was to route the BenQ signals to the sharp Inverter, and I shorted the two control inputs.
Secondly the 5V was applied to the DSP, and for the time being I used the audio amp to test audio and the power for this was also no problem. The two pins left from the inverter was, as I assumed to control the back light brilliance to acomodate for the room illuminance and the likes and is left to be checked once I get into the system menu of the TV.
So after carefully mounting the sharp PSU to the BenQ chassis, and nicely cable tying the wires, crossed my fingers and powered.
The stand by light lit, and the press of the power a few relay clicks and viola!!
The TV came to life, and it stayed on. I was soooooooooooo happy.
Below is the final assembly, notice the cable routing and the 5V supply at the back of the main PSU. ( Sorry for the dark picture, I forgot tht the flash didn't go off)
![[IMG]](proxy.php?image=http%3A%2F%2Fi702.photobucket.com%2Falbums%2Fww28%2FRifaa-ath%2F100_8868.jpg&hash=9b9596db2e9d3bff6d5ee73dbec36c72)
(PS. If you like I can take a clear picture and label the parts, but you have to request since the TV is in my room now)
A real funny thing happened, remember about the left out pins of the inverter brilliance control, well guess what, when I played with the menu settings, the back lit works, when switched from dark, normal to bright. 😕😕
And to think that there is no connection that could possibly control that what so ever, I mean I made no connection except the 400V DC, 12V Vcc, GND, and the joint two control pins. So how the heck is the BenQ DSP is controlling the sharp inverters light output. ****Miracle****. what else. 😒. .....what do you think. Still, I ain't touching that part since it's working, one rule, if it works leave it.
#-Link-Snipped-#
Below is a pic of the tube connection and powered up.
Next was to mount the Inverter. Since the BenQ one was of low profile type, the sharp one will never fit the BenQ's inverter mounts. Again I have to compromise.
I have to get rid off the BenQ speakers to mount the Inverter, Since the Tube connectors have HV Insulation and any longer wire than necessary will tend to generate a lot of EMI, second getting HV insulated wires is impossible here, and also the mechanical work associated in all these modification will cost a lot and will take a lot of time, this was the best option. Besides I never like the small speakers it has, and I have a 7.1 one custom built sound system with my HTPC, I do not need any more speakers. 😛. And my audio Rocks. hehehe!!
In the second picture u can see the plastic I used to insulate the inverter since I got electrocuted ones or twice without it. I'll say it was quite an experience touching the HV.
The plastic is quite nice isn't it, I have a cousin who is in business with laser cutting and engraving all kind of materials. The laser engraver is quite unique and one of a kind here, I can make any thing with it, and I am thinking of making bezel facia for this TV, with all the art works and stuff, but that will be a bit later.
The plastic provides a solid mount to the chassis.
The tube connections a kept to a minimum and has HV heat shrink tubing to prevent unnecessary arching to the chassis. Still I donno how long the insulation will hold, it is yet to be tested how long it will take the tubing to degrade.
Finally Inverter Assembled
Next comes the PSU modification, but before that a lot of measurements were taken about the voltages and current ratings. I wasn't going to use both the supplies in it, no place to mount and it will generate too much heat and consume unnecessary power.
Initial testing was done without the inverter and with the benQ PSU to see how much power is consumed by the panel and the axillary circuits.
The BenQ Panel was using the LVDS signal and mainly the Auxillary supply like 3.3V, 2.5V and 1.2V that was neccessary for the panel and DSP is regulated by onboard switching regulators on the DSP Assy and all it needs was 12V @ 0.5A and a 5V at around 1.5A tops. The audio amp uses complementary 16V supply and the inverter is powered by a bulk 14V.
The switching voltage necessary to turn on the PSU from stand by and inverter is @ 3V. Plus a stand by 5V @ 0.5A.
Since I attended the sharp PSU before I was quite familiar with it's voltages. 400V DC to the Inverter, Complementary 14V to the audio, two 3.3V @ 1.5A, 6V @ 1.5A and a stand by of 3.3V.
So replacing the BenQ PSU with the sharp one is childs play. Only problem was the ever 5V needed by the BenQ DSP, and it will not operate if it drops even by 0.5V.
I have to use a seperate 5V PSU to oparate the BenQ DSP at stand by and modifiying the sharp ever 3.3V is really difficult since this ever 3.3V feed back loop is cuopled with the charge pump circuit in the sharp PSU, any change I brought to increase the 3.3V to 5V hinders with charge pump operation. And making a charge pump takes more time, and I was in such a hurry to get the TV in to my room 😛.
Here you can see a small 5V PSU I salvaged from my junk. suites well, doesn't it? Well that's settled.
Next was to modify the out puts of sharp PSU. A quick reference to the data sheets of the regulators used in the PSU secondary showed it's easy to generate at least 5V difference as long as the voltage does not go below it's rated output, since these were switched mode regulators. it was easy.
The 3.3V was not necessary, so it's regulators were omitted and the fault detecting circuits were bypassed for this output and the 6V feed back was increased to decrease the output to 5V. Since the sharp PSU and the benQ regulators were of type 1.5A current ratings, It was not necessary to even check if the supply could handle the current, something I learned over the years, Just by looking at the regulators, transformer, inductor and the caps I can assume it's power handling capacity. The Audio supply is OK since I don't need them but to test, and almost all audio amps can handle a change in plus minus 5V or so provided the out put level is kept low.
Here is a pic of the benQ back before the removal of it's supply.
Now with ever 5V added, it was time to see if the BenQ processor worked switching it's control terminals. There was only one switched out to the PSU. All the rest are powered up when the supply switches on.
The Sharp Inverter has more terminals than I bargained for, at least seven, as a rule of thumb, there will be +Vcc, GND, fault feed back and the back lit brilliance control, still 3 is left and I have no idea what the heck those 3 does, so a quick fiddling was necessary. It seems that the control pin has two inputs which has a high input of 3.3V to be activated for the inverter to power up. The Inverter 400V DC is separate and is powered when the PSU switches on, so that was settled, now since I am using the sharp PSU, getting the supply for the low voltage side of the inverter was no problem, all I have to do was to route the BenQ signals to the sharp Inverter, and I shorted the two control inputs.
Secondly the 5V was applied to the DSP, and for the time being I used the audio amp to test audio and the power for this was also no problem. The two pins left from the inverter was, as I assumed to control the back light brilliance to acomodate for the room illuminance and the likes and is left to be checked once I get into the system menu of the TV.
So after carefully mounting the sharp PSU to the BenQ chassis, and nicely cable tying the wires, crossed my fingers and powered.
The stand by light lit, and the press of the power a few relay clicks and viola!!
The TV came to life, and it stayed on. I was soooooooooooo happy.
Below is the final assembly, notice the cable routing and the 5V supply at the back of the main PSU. ( Sorry for the dark picture, I forgot tht the flash didn't go off)
(PS. If you like I can take a clear picture and label the parts, but you have to request since the TV is in my room now)
A real funny thing happened, remember about the left out pins of the inverter brilliance control, well guess what, when I played with the menu settings, the back lit works, when switched from dark, normal to bright. 😕😕
And to think that there is no connection that could possibly control that what so ever, I mean I made no connection except the 400V DC, 12V Vcc, GND, and the joint two control pins. So how the heck is the BenQ DSP is controlling the sharp inverters light output. ****Miracle****. what else. 😒. .....what do you think. Still, I ain't touching that part since it's working, one rule, if it works leave it.
#-Link-Snipped-#
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