timwiththebo

I have just spent the best part of today carefully installing my lilliput screen into the TM-701L case from digitalww. When I got to the testing stage nothing happened.

On inspecting the problem I found that the voltage was immediately dropping to almost zero as soon as I connected the power - I presume this is a short but have searched and searched to find no clues.

I am now at the stage where I have re-assembled the lilliput, as much as I could, back to its original form... still no joy.

I have checked connections over and over again and found no obvious problems - can anyone help me... pleeease?!

Have I fried or overheated my board?

Thanks in advance for any advice

MP3Car.com

 

shchua

Use an multimeter and measure the resistance between the pins on the Lilliput's power input jack (place the red or +ve probe on the centre pin and black or -ve probe on the outer pin). If the resistance is a dead short, check the areas that you soldered for solder balls that could have shorted across to another track. Check both sides of the board - solder balls often form on the reverse side of the board when excess solder is applied and are hidden from view. Pay special attention to the pads that carry power and look out for solder whiskers as well.

timwiththebo

Thanks for the advice Shchua, I did a check and found no shorts, excess solder etc. (I have a useful mulitmeter option that just beeps when there is a direct connection between the two probes - perfect for finding shorts and checking solder connections!)

I actually woke up to a PM from Masch who suggested that I tried the old USB cable and see whether I received any power via that - I did and everything worked!

I have now being trying different possibilities of powering the controller board and have found that when I hard wire the controller direct from the power source the screen is all fully fuctional. However, when I try to power the screen through the TM-701L wiring loom, the power light turns on at the front but I can't seem to turn the screen on.

When I revert back to the direct wiring option the screen is fully fuctional again - do you have any ideas what is happening?

To clarify,

Direct wiring:
Supplied Lilliput transformer ---> Supplied Lilliput USB cable ---> USB cable cut and wired direct into board.

Wiring via TM-701L:
Supplied Lilliput transformer ---> Supplied Lilliput USB cable ---> USB cable cut and wired direct to supplied TM-701L casing power lines (the cable with Video 1 & 2)

I just can't understand what is going on, can any of you bright sparks shed any light on my problem?!

Look forward to any suggestions

shchua

Hmm, it looks like the problem may be in the wiring that came with the in-dash housing. I suspect that the wiring resistance is higher than normal - this will allow the red LED on the front panel to turn on but prevent the monitor from turning on properly (excessive voltage drop when the monitor tries to draw full operating current). I'd suggest checking the resistance of the GND and +12V lines from the small circuit board at the back to the ribbon cable in the monitor housing. Watch out for obvious things like a kinked flex cable or loose connections at both of the flex cable connectors.

Edit: Also, make sure that your +12V is wired correctly. If +12V is supplied to V1 or V2 instead, there might be enough leakage current to light up the front panel LED but not enough to power the monitor on completely !

CdRsKuLL

check the ribbon cable to the buttons, I found if this was slightly off it wouldnt work

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JayKaye

I had a similar problem with my lilliput not working when inside the case and using the supplied cables but working when not using the cables. Turns out the filter that comes with the housing was doing something to stop it from working. Once I removed the filter (cut it off) everything worked fine.
I wish I could say that the resistance was too high in the filter, but that would be pretending I know what im talking about :P

Good luck and let us know how you go!

timwiththebo

Having tried putting power in at different points along the 12v line I have found and can confirm with JayKaye that the 12v filter is the problem.

Too pleased for words that I've finally located the problem, but too annoyed that it was something this simple.

Thanks so much for the post JayKaye, if only I had started this thread earlier rather than trying to work it out myself.

Anyway, the end result is good and we need to make sure that other people that try this conversion are aware of this problem. I will write to Armen and try to get him to include a warning note with the TM-701L housing saying that if you occur a power problem, try bypassing the 12v filter. Also, if he could update his install guide that could help as well.

Also thanks to the guys above: Schua, CdRsKull and JayKaye - you've showed what a good forum can do for me!

archimense

I'm in the middle of my Lilliput in-dash conversion, so thanks for the heads up.

JayKaye

Glad I could help it took me a while to figure it out myself. Once everything is done with my car PC I will be writing up an installation guide as I feel the one on Armens site could be improved upon a little.

antimatter

I second that comment about the ribbon cables. I thought i broke mine when i put in the power and nothing happened after removing and replacing small ribon cable to the buttons.

I found that the ribbon cable had to be slightly to one side or it wouldn't power on

Thats most likly the problem if you didn't drop it and there is no shorts.

It took me a good 1/2hour playing around with that ribon cable to get it to work

Good Luck

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timwiththebo

Ok, so I thought I was on the home straight, I had worked out the power problem and the screen was fully working.

I had wired the new buttons in and checked again that the screen was still working - it was, brilliant.

Next step, I unsoldered the vga and touch cable and resoldered my 10 line ribon cable, I checked again that the screen was still working - it was NOT, disaster.

I am still getting power to the board and the red power indicator still lights up. However, when I press the power button nothing happens.

I have searched the board for solder blots, mistakes etc. but can't see anything. Anyone have any ideas?

I am being plagued with problems during this conversion but am determined not to be defeated!

Cheers for any suggestions.

shchua

You're almost there. Try the following:

a. Unsolder the ribbon cable from the LCD and touch controller pads,
b. Power on and check if the monitor powers up (LED goes green, NO SIGNAL shown on the screen)
c. If it doesn't, go back and check your soldering and wiring. Sometimes, wires break loose due to cold solder joints and repeated flexing.
d. If it does, solder the ribbon cable to the LCD and touch controller and test. If it works, you're home free.

BTW, what filter are you referring to ? I remember seeing a fusible resistor on the incoming 12V line. Its not a good idea to bypass this as it serves to protect the monitor against overcurrent (due to various malfunctions). Once it is bypassed, you run the risk of damaging the monitor severely if there is a fault condition, eg blowing PCB traces, releasing the magic smoke from components ...

JayKaye

shchua, the filter he is referring to is the black box with the word 'filter' on it in the middle of the red (positive) wire that comes with the housing. I had to remove my filter also as there is no other way to power the screen.


As for the problem at hand. The signal wires have nothing to do with power, so im guessing youve broken a soldered joint or snapped a wire somewhere. Usually I just check them all with a multimeter and if need be resolder them all again. But then again I got all the correct tools here to do that without damaging the board.
In the future, after testing the screen and its working, use the glue gun to secure the wires in their places. Dont use too much but enough to ensure the solder point is fully covered. Once youve used the glue gun on a point its not meant to come off, so make sure its working properly before gluing.

Good luck.

Curiosity

Since this comes up a lot and I had nothing bettter to do, here's some pics to reference for the noobs. 1. The controls connector out. 2. Connector in. It's looking down, though. I got a shot of the little space on the left (right) side, and how the connector opens! The IR sensor is supposed to be in that open space though.

Attached Images

  

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Skraggy_uk

Just a thought here if you are testing out of the car using the 12v DC transformer.

That enclosure is for in car so should be able to handle a peak running voltage of 14V. the filter will clean that up, and regulate it to 12v I assume, so there will be a voltage drop.

If the transformer is providing 12v and the filter tries to drop 2v, will the screen turn on with 10v?

Could that be the problem. Has anyone tried using the enclosure straight from a running car rather than with a transformer, with the filter in place using a meter inplace instead of the screen or controller?

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