Re-using a Broken Television as a Monitor

or

What To Do With a Broken Television when You Can't Fix It

I was given a broken television.  Technically this television was doubly broken: once when the HDMI inputs stopped working and once when everything stopped working. After the first fault it was taken to a television repair shop (yes, they do still exist) and they couldn't fix it as the parts are not available. I had a look at it on that occasion and found that some RGB inputs did still work, so we fed a signal in there and that allowed the television to live a little longer.

After the second failure nothing appeared on the screen at all, and the backlight did not switch on, so I was given the television to see if I could fix it or do something with it.

The television is an LG 39LE4900 and looks like almost every other television on the planet. Once opened I found a power supply PCB

 and a control PCB:

I also found an inverter PCB, under a metal cover, which powers the backlights:

and what I later found out was a TCON PCB, also under a metal cover:

I had a quick look at the boards and nothing seemed to be obviously wrong. When I powered the television up nothing appeared on the screen and the backlights were off. The remote control worked, in that it turned the television on, but nothing appeared on the screen. I used a torch to see if the LCD was displaying something even though the backlights were off and it wasn't.

I managed to find a service manual on the internet for a similar model, but the control PCB was the only board that the manual had schematics for. I thought this was a bit odd at the time, but it actually makes sense, I'll explain later. unfortunately, as the service manual model wasn't exactly the model I had, all of the component numbers were different to my PCB. I could work out that there was basically one large, presumably custom, chip that controlled almost everything. I checked voltages of power supplies and everything seemed fine.

I also tried to find a serial output from the board that worked, but no luck.

The next step was to get some replacement PCBs from ebay. I did this and eventually replaced all of the PCBs and found that the television still didn't work. This was a bit odd. I then took the step of buying a complete new screen (and a couple more PCBs) to see if that would work with the old and new PCBs. It didn't. This was a bit surprising as I had expected to get something working at this point. 

I then started looking at the PCBs in more detail and found that the TCON board and inverter were made by AUO, and there was actually a datasheet for them. Well, sort of. There was a datasheet for the LCD and backlight and TCON and inverter PCBs, all bundled as a module. AUO seems to sell this as a module that manufacturers can use in their products. LG have done this and then added a PSU and controller PCB. This explains why the controller was the only PCB with schematics in the service manual. The  rest of the electronics was bought in. (Except maybe the PSU which I think is a standard LG board).

The LCD/backlights/TCON/Inverter can be thought of as a larger version of a 16x02 LCD module. That also has a display, backlight, and driver circuit. The only difference is the size of the LCD and the interface used. With the AUO datasheet I now had details of the two connectors that the module provides, one for data and one for backlight. The data input is LVDS.

After another search, I found that the schematic for the PSU PCB was also on the internet, which was useful as I could then hardwire the supply to the LCD backlights. After having done this, I found that the backlights worked fine on both screens. This was good news.

 I then decided that fixing the television wasn't really practical, but I might stand a chance at turning it into a monitor. I'd recently fixed the display on my Novena

 

 laptop so had played around with LCD panels and knew I could get cheap driver PCBs that would take VGA or HDMI and drive an LVDS interface.

I decided to make a hacked together VGA to LVDS adapter PCB attached to a flat cable connector adapter PCB. The VGA/LVDS adapter needs +5V, whereas the PSU PCB in the television only provided +24V or +12V so I had to also use a DC-DC converter to power it. I hardwired the LVDS signals from the adapter PCB to the flat cable PCB using wires. I cut the connector that the adapter PCB supplied off the end.

Once this monster was all wired up and attached to the television, power was applied and a laptop supplied a VGA signal. And it worked. the picture was upside down, but the laptop could flip that and once done the television now displayed a nice stable picture. Well, it did when I could accurately and firmly attach the flat cable from my PCB to the TCON board. I'd been unable to get the connector that the LG control board used, so I'd bought the one that the TCON board used. This connector rather than being the FPC type connector that attaches to the end of the flat cable, attached to a connector that fits round the end of the cable. 

 

This meant that I had to use a piece of folded paper to hold the bare flat cable in ot the connector. I also tried 3D printing a flat spacer to wedge in the socket, but it wasn't ideal. In the end I bought a couple of new cables that were the same length as the original but had the connector on both ends rather than just one end. These work perfectly.

 With this mess of wires and boards working I decided to make a PCB. This would mean that the electronics and wiring could be tidied up and I could use one PCB rather than two or three. 

 

The VGA LVDS adapter was mounted on the new PCB, as was the DC-DC converter. The footprint I used for the converter was a very generic one, which lets me wire almost any DC-D converter I can find on to the board. The wiring holds the converter in place.

I also put a footprint for a Blue Pill on this PCB so I have the option of using that to perform housekeeping functions like turning the supply on and off and providing a timer to turn off the screen after a certain time. I haven't used the Blue pill to do this yet, I just turn the monitor on and off at the mains.

I can also use this PCB as a general Blue pill breakout PCB. I have five PCBs and will probably only ever use two, so the other three can be repurposed.

The PCB fits nicely in on the mounting holes that the AUO module provides, and the VGA connector is accessible once some metalwork has bee cut away.

I've been using the monitor for a few weeks now and it seems ot work fine. I'm making a PCB for the second screen as well, so I'll have that up and running too, I hope. I checked the screen with the first PCB I made and it does also work.

Why the televisions didn't work with the new control PCBs I don't know. I have tested every other PCB I bought and they all work fine. Are the controllers broken? Or do they need some magic setup? I don't know. I'm going to strip them for parts.

Details

The connection between the TCON PCB and the VGA-LVDS adapter:

The 12V supply was used to power the TCON board. The VGA-LVDS PCB needed +5V so the DC-DC converter was used to provide that. I used a variable DC-DC onverter and set it to +5V running from the +12V supply. I measured about 500mA drawn by the adapter so used 1.5A or 2A converters.

The PSU was hardwired to power on. This was done with a wire link on the PSU PCB. Using the schematic I managed to find an appropriate supply and signal to use. (PWR_ON connected to 3V5).

Connections between TCON and LVDS adapter:

VGA-LVDS                TCON

O0+    O0-                CH1_0+    CH1_0-

O1+    O1-                CH1_1+    CH1_1- 

O2+    O2-                CH1_2+    CH1_2-

GND                         GND

OC+    OC-               CH1_CLK+    CH1_CLK-

O3+    O3-                CH1_3+    CH1_3-

E0+    E0-                CH2_0+    CH2_0-

E1+    E1-                CH2_1+    CH2_1- 

E2+    E2-                CH2_2+    CH2_2-

GND                         GND

EC+    EC-               CH2_CLK+    CH2_CLK-

E3+    E3-                CH2_3+    CH2_3-

                                  VDD  +12V

                                LVDS_SEL: Open (HS)

(Closed is JEIDA, which didn't seem correct from the AUO datasheet)

 

Videos

I have a series of videos that show the work I did.

 

 

 

Novena Laptop Fix

Novena Laptop Fix

I got a Novena laptop from Crowd Supply several years ago. 

 

 

I didn't use it too much and that probably contributed to the batteries not being charged enough to maintain good health. That lead to some magic smoke being released from the battery charger PCB. It looks OK in this photo, but it's not.

 

 

The laptop was dead at that point. Being open hardware, though, means that I have all the schematics, gerbers and firmware for the system, so it should be fixable.

I decided to change the Novena to a desktop system, so I removed the battery charger PCB and tried powering from the power socket that is on the main PCB. That seemed to work, in that it powered the main PCB, but the LCD didn't come up and there seemed to be a configuration problem. The push button at the front of the machine also didn't work.

It turns out that to run the Novena as a desktop you need a different PCB where the Senoko PCB lives. It's called the 'Senoko pass through' PCB and the Gerbers are available. I had some made and populated a couple. 

 

 

 

Once fitted in the Novena all was well and the power supply can now be turned on using the button on the front of the case.

The display still didn't work, though. After looking at the schematics I came to the conclusion that a high voltage had travelled down the I2C bus that the battery controller was on and had destroyed anything on there. That unfortunately included the LVDS to eDP video converter chip. Well, that's not too much of a problem as the chip is still available ( I bought a few) and the PCB gerbers are available as well. So I had a few of those made up and populated two of them. 

 

 

 

This PCB was much harder to populate as the BOM wasn't online (I subsequently got a copy) and so some of the components I used weren't exactly the right footprint. The packages used by these components were also in the 'nasty to handsolder' category.  I tried both PCBs and neither came up with a display on the LCD. Was it the layer stack up? Maybe as I just had the PCBs made using my usual cheap supplier and didn't pay any attention to layer stack up. Was it my soldering or the footprint problems? More likely. Either way I still had no LCD display. Did the LCD get blown up? That was possible, so I bought a second LCD panel and tried that. 

 

 

 

No output on any eDP PCB. 

 

I then noticed that you can buy cheap HDMI to eDP converter boards and got a couple of those. Attached to the HDMI port of the Novena and attached to the second LCD I had bought, we had output. The HDMI output still worked and I had verification that the LCD I had bought worked. having an HDMI cable running from the external connector into the case and through a converter PCB to the LCD was untidy though. 

Could I have damaged the mainboard somehow and the LVDS was broken? Maybe, so I bought a new mainboard as they were on sale. I tried that and the same result. No LCD output. 

 

After more searching online I found that you can buy LVDS to eDP converter PCBs that use the same chip that the Novena eDP board uses. I bought one of those and started to investigate wiring it up to the LCD and the Novena mainboard. It wasn't an easy job. Before I finished doing that (or actually, even started wiring), I remembered that I had some spare LVDS to eDP chips that I bought to populate the eDP PCBs. I could remove the chip from the eDP board I got with the Novena and put a new one on. That board wouldn't have the possible layer stack up problem or footprint/component problems of the boards I'd made from scratch. I swapped the chip and tried that. Still no luck. This wasn't looking good. I swapped the mainboards around and still no luck. 

The debug serial port spits out information about the setup as the Novena boot sand I noticed that the LVDS to eDP chip was recognised but didn't get powered up. I fiddled with the EEPROM settings but still no display. The chip seemed fine though, so my swap seemed to be OK.

I then booted into recovery mode, I can't remember why now, probably as it was another option to investigate the disabling of the LCD. I had the Novena facing me (the case opens in the opposite way to a normal laptop), so the LCD was facing away from me. As I booted I suddenly noticed that there was a reflection of the LCD on the screen of my logic analyser. the LCD had started up!

This was good news, but why was it on now? The only thing I could think of was that the disabling of the LCD was now a software problem, the hardware was functioning. Normal boot on the mainboard I had in the Novena was disabling the LCD for some reason. Which main board was I using? Well, it was the new one that I had bought, and that was part of a 'just the board' kit, so it may not have been configured for an LCD, rather to run as a server. I swapped the SD cards between mainboards and rebooted. The LCD worked fine. So maybe that theory was correct and my later problems after the chip swap were due to the SD card configuration. I've not found the setting for the LCD disable, partly due to taking a break after all the kerfuffle.

Plantation Shutter Fix

Plantation Shutter Fix

When you make something, you can fix it. Fixing is just a smaller job than the initial build. Years ago now I made plantation shutters for most of our windows. The shutters are in panels and usually four panels are used per window.

Until recently they had worked fine, but as the children have been messing about with them I fully expected them to break something. As it turned out the first breakage of shutters was done by me. I caught my trousers on a 'safety' corner thing that I had screwed to our coffee table. As I got off the sofa my foot refused to reach the ground and due to the trousers wrapping themselves around the safety item it also refused to detach from the table corner. I crashed into a shutter panel and broke two slats.

I try to use screws instead of glue and I screwed these panels together. This means I can easily dismantle the panels when repair is needed.

Once the side has been removed I can access the slats. They are stapled to the control rod, but I don't need to unstaple them for this repair. Once I saw the end of the slats I found that four were broken, not two.

I could make some more slats if I absolutely had to, but decided to attempt a repair as most of the slats have just end damage.

Most of the slats have all the wood still attached, so I glue them up, but one slat has a chunk taken out of it and no wood remaining. For this one I use a small piece of wood shaped to the hole in the slat. This is then glued in to place.

All the slats are then clamped and left to dry:

 Once they have dried, they don't look too different:

That's what watching glue dry is like. The larger wooden block I glued in place needs to be cut down.

I started with my new crane knife, but the job was a bit big for it, so I moved on to a Japanese saw and removed most of it.

I then continued with the crane and got the repair close to the slat profile.

I have found that a black sharpie can be used to touch up dings in the stained wood. The stain I use is an Osmo ebony and the Sharpie matches it really well.

That's the slats with the fixes touched up.
Re-assembly is the reverse of assembly, as always and the fixed panel is revealed:

Fixed.

Tumble Dryer Alarm Clock

It looks like my tumble dryer has an alarm built in to it that wakes me up about once a year. Last year it was a clacking clanking scraping sound (see here).

This year it's a thump thump-thump sound. (Sort of D in Morse code). OK, it's 1:30am so I don't get up, but try to sleep through it. After a couple of hours the dryer finishes its program and I get some sleep. Five o'clock comes round and I get up and investigate.

I've forgotten how to get the top off properly (just undo the side screws and the top comes off to the front. Don't undo the rear screws like I did. Again). To get the sides off I need to take the front panel off and to do that I need to take the bottom vent off. I forgot that it slides on these clips:

I finally have the top and two sides off and can now look for the D-thump. Turning the drum manually I can just feel a bump now and again. The rear bearings look fine, so I have a look at the rollers. They are fine too. Then I notice the drum has some black marks where something has stuck to the track the rollers run in.

I find that there's a big blob and several smaller blobs, which probably accounts for the D pattern of thumping. I scrape the blobs off with a wooden stick and re-assemble the dryer.

A quick test and the D-thump is gone. I have no idea what the black blobs were. At first I thought it might be material from the rollers, but they look fine, with no obvious missing material. Maybe something fell onto a roller and ended up smeared around the drum?  I have no idea, but the dryer seems well again, which is good.

Fix of a Fix

The tripod I use broke a couple of years after I bought it. I think i dropped the tripod, or it fell over, I can't remember. I didn't want to throw it away and I must have just built my first 3D printer, so I modelled and printed a new part for it. A while later another clamp on the tripod failed, so I modelled that (it was a different size) and fixed that problem.

Recently I had started to notice that one replaced clamp was a bit loose. Of course, I carried on using the tripod until the part failed, which is did a few days ago.

The broken part is here:

I think this was printed on my Mendel, but however I did it it looks like I was using very little infill at the time. You can see here

that there's none, really.


I printed the new part at a higher infill figure (50%) and also at a layer height of 0.1mm rather than 0.2mm. This leads to a denser part that hopefully will last a bit longer than the original.

Fixing a Panasonic H-FS014042 Lens

I use Panasonic GF1 and GF3 cameras for stills and video. I use the 20mm lens that came with a GF1 and also a selection of Pentax lenses and micro four thirds adapters. The 20mm is an auto focus lens, but all of the others are manual focus. This is fine in the workshop when shooting video or taking macro shots of bits and pieces, but when out and about it's a lot more convenient using auto focus. I've been looking for a zoom lens for the cameras for weeks. they are quite expensive, probably because they can be used on a wide range of cameras. Not wanting to spend much money on the lens, I waited until a broken one came up for sale that I thought I had a chance of fixing.


The lens I bought had probably been dropped and the mounting flanges had broken off. I removed the part that was broken:

I tried the most sensible route to a fix: try to buy spare parts. As usual, they aren't available. I was told that my best course of action was to have the lens serviced at an authorised service centre. I suspect this would have cost more than I paid for all of the GF cameras and lenses put together.
So, instead of this I decided to have a go at making the part myself. I have a 3D printer and this is a plastic part...

Here's one of the prototypes I made along the way:

Did it work? Well, yes it did. In fact the first two photos in this blog entry were taken with the previously broken lens.

This photo wasn't, for obvious reasons:

I do get a few lens attachment errors ( I think the contacts need to be moved up a bit), and I lost a screw (not technically lost I suppose, I know where it is: somewhere in the workshop), I have only aligned two of the four mounting screws and I have to drill a few holes by hand, but it does work.

Auto focus and everything.

It works as it is, but I'll probably improve it to remove the annoying lens attachment warning. Just because it isn't perfect doesn't mean it won't do the job.

Canon Selphy 740 Fix

I recently bought a canon Selphy photo printer in a charity shop. It was cheap and seemed like a good source of parts if it didn't work and an interesting colour printer if it did (although the paper and ink cartridges are expensive).

It didn't work.

I took it apart and at first sight couldn't see much wrong with it. It was very clean and in very good shape. One odd thing was that I couldn't get the printer ink (or film, to be more accurate, this printer doesn't use ink, more on that later) cartridge out of the printer. Even when dismantled, I couldn't get it out by springing catches open and so on. I then noticed that there was a small electric motor which didn't have any gear on it's spindle. That can't be right. Then I noticed a rattle as I turned the printer over and then out popped a small gear. It was exactly the correct size to drive the larger gear next to the motor spindle. You can just about see the small crack in the gear that caused it to fall off the spindle in this photo:

For some idea of scale, that's a 1.5mm hole in the centre of the gear.

The first thing I do with these fixes is try to get a real part, but I've only managed that once in the past, most manufacturers won't or don't sell spare parts. That was the case here. So it was either fix the gear or make a new one. I've not had much luck in fixing these gears in the past, so I decided to make one.

I created a script that generates Gcode for this gear (it's parametric so I can use it for other gears too), and set my CNC machine off to make a new gear.

The cutter is a 0.2mm D bit that I ground the end off to make it more closely match the profile of the gear. It's not perfect but it works.

I used a surplus stylus that I got with a TFT display, as the stock for the gear. It's a bit soft and if it fails I'll look at another material, perhaps.

You can see the profile of the gear I cut here, together with the real part:

You can see that it's not a perfect match, if I need to then I can cut a better one.

Here it is in position in the printer:

The new gear fixed the printer, it can now print:

This printer uses film, not ink, as I mentioned before. There's a yellow, a cyan and a magenta block of pigment on the tape that is in the cartridge, one set per photo to be printed. The printer goes through four printing cycles but I've only found three pigments on the tape, I'm not sure what the fourth stage is. Anyway, I noticed that the used tape had a reverse image in each colour on the tape. You can see part of an image here:

These correspond to the pigment that is left in the cartridge after an image has been printed. This means that you can rewind the cartridge, put it in the printer and, if you print a totally black image, print a colour negative version of the photos that were printed by the printer. That can then be scanned or photographed and colour reversed in software.

More 3D Printing Usefulness

A colleague has a clothes dryer that came with two feet used to attach it over bath. The feet sit over the side of the bath and the other side of the A frame design sits next to the wall. This is fine if you have only one side to load up with clothes, but if you want to spin it round 180 degrees and load the other side then there's no feet on the side that is now on the edge of the bath. The dryer has the holes for the other two feet, they just weren't supplied.

A foot:

There's a screw that fixes the foot to the frame, there's four holes for feet, only two feet. The screw is countersunk so it doesn't damage the surface the foot rest on.

An OpenSCAD model later and we have prototype one:

This was fine, except that I'd left out the countersinking of the screw and the screw hole was too big.
Prototype two has the countersinking.

I printed two of the latest version and so far it looks like they do the job.

Fisher 3D Printer Widget

This isn't for either of my Fishers, rather it is for a friend who has a Fisher that only prints when the Bowden tube is held in a particular orientation. This is odd and hopefully a proper solution will come forth. Until it does, I knocked up a widget that hopefully will perform the 'holding in a particular position' job. The position is vertical, so it was easy to make this widget on the lathe:

The pneumatic fitting is the latest way that the Fisher attaches the Bowden tube to the effector. Both of my printers have the tube screwed directly into he heatsink. The tube comes out at quite an angle and I see no problems.

The widget has a hole each end, one for the tube:

and one for the pneumatic fitting:

The fitting is a (very) snug fit into the end:

The flat is to provide some clearance for the fan which is close to the tube entry point. This could maybe have been 3D printed, but I didn't have any dimensions for the part, other than a 4mm hole for the tube. I machined the fitting hole by performing many test fits as I bored the hole out. To 3D print this would have taken many prints to get the correct fit. Hopefully Aluminium is a bit more rigid and durable than PLA.

Lamy Pico Fix

My Lamy Pico pen

that goes everywhere with me broke recently. It had been sticking when telescoping it, but I hadn't realised why. I thoughty there'd been a build up of fluff or something, but it turned out that the end had broken. You can see on the right hand side of the pen that it's at an angle. the thread has broken on the part that is unscrewed when replacing the refill. This is a shame. I could get it repaired, but even then it's likely that the same thing would happen. So I decided to have a go at making a new part.

I dismantled the broken part. There's a spring and a sliding part that holds the refill. The pen telescopes, so there's quite a bit of movement of the refill.

I realised that I could re-use these parts, although I have ordered some bits and bobs if I want to have a go at completely replacing them.

This is the sort of job that I got a lathe for, so I found some brass rod, and machined a replacement part from solid brass.

I took dimensions from the original, which gave me a starting point. The thread was 11.4mm x 0.8mm pitch, if anyone wants to do this themselves. That thread fits nicely in the barrel of the pen. I manually adjusted the part to make it work with the telescoping mechanism. This was a bit tricky as it didn't work too well at the start, but by removing small amounts of material I got it working as well as the original.

I used abrasive paper and a burnish to finish the outside, and it fits well on the pen:

I added the radius on the end using a file on the lathe. I have no radius turning tool for my lathe.

The pen when in the extended position:

The extra material is noticeable, but not unpleasant, and the brass is nice and shiny. I may remove the paint on the pen to match the new part, or I may not. I'm undecided at the moment. It may be a good idea as it is wearing off anyway in places, so would be neater if removed.


I've done a video of this, if you want to see it moving: