Uni-t UTi260B

[Nick2theD]

One thing that is bugging me.  I have the new buck converter and old in front of me.  worked out now that
testing resistance from the bottom negative pin to the input recreates the original test you told me to do.   The original reads about 190.  The new one has no reading at all in any multimetre mode i have tested.   I don't know if this means anything but it was bugging me your repaired unit had 2 hundred and something and my new converter has no resistance reading with this test...

Thanks

Nick.

[Fraser]

The peculiarities of in circuit testing of the input to a buck boost converter. Testing out of circuit is not the same as the IC is not configured for operation. Remember, a multimeter uses a stimulation voltage to measure resistance. In the case of my Fluke 87 III it is less than 1.3V. This voltage is feeding into the input of an active voltage converter and not a passive component. All the resistance reading tells us is that the input is not at a low resistance, suggesting failure. My readings started at 500 K Ohms and reduced to around 200K Ohms. That is a healthy resistance. We are using the multimeters resistance range as an indicator of circuit health, not for an exact resistance measurement. Out of circuit, the pins of the IC are all floating and it is not configured for operation. Not the same situation as when in-circuit.

[Chupacabras]

Is it possible to freeze range of temperatures? Some static scale?

When I look at some object and move camera around it, the range/scale always changes according to actually viewed image. And red or blue color from some angle has different temperature than red or blue color from different angle.
I would like to freeze the range so when I move around some object so the same color is always the same temperature.

Currently when I view some part of say PCB, some spot is very hot, there are temperatures from 20C to 80C, so the one spot is red, I know it is hot. Then I move camera to different part, where are temperatures from 20C to 30C, and again that 30C area is red. Which is confusing.
I would like to lock that range, and than move camera around. Is that possible?

[Fraser]

The power section MOSFET voltages for the camera OFF and ON states, in case this information is useful to someone.

Note that the measurements were taken whilst the camera was running on its own internal battery. The Battery started out at 4.11V (fully charged). Once the camera is on, the battery p.d. does drop a little.

I have reverse engineered the UTi260B power sub systems so can help with questions relating to that area of the camera. The schematics are in my "shorthand" and are not for public release at this time.

Fraser

Update: MOSFET datasheets for "01AH" and "7002" added. 01AH may be replaced with a IRLML6402TRPBF.

[Nick2theD]

This has got progressively worse for me. I thought i had u6 installed perfectly yesterday.  tried it and the buck booster got red hot.  testing the pins well it was in the unit i found a short from ground to one of the inductor pins.  I think this is why it got hot.   Took it off today.  Attempted to solder mask to make the job easier,  didn't do a bad job.  It didn't stand up to the flux and tinning though and so contaminated everything.   more cleaning, more solder mask removed. All the left side pins are a single long bar now.  creeping around to the bottom left pin.   absolute disaster really.  Not impossible to rite but a mess.   L1 inductor and the cap is it? where i was testing for 3.3v came off.  cleaned them up, cleaned board up.    The new U6 will be here tomorrow, not sure if it is even possible it put it down now.  without the left side pine pads for reference, Nightmare.

[Fraser]

Not great news

All is not lost though. We are some ways off declaring the patient beyond help but you have a lot of work to do.

Your comment on the solder mask interested me. Did you use a strong UV light source to properly cure the solder mask ? Some weak UV light sources or ones operating at the wrong wavelength can cause the mask to not cure properly. Once cured, it should be impervious to flux and solder. A problem with manually applied solder mask under a leadless IC is the potential to use too much and this creates a bump of solder mask that takes time to cure and prevents the leadless IC package sitting flat on the PCB.

Good luck with your efforts to repair the camera.

Fraser

[Fraser]

Please supply a picture of the PCB as it is today so that I may assess the patient

I presume you still have the components that tried to escape from the PCB (Capacitor and Inductor)?

Fraser

[Nick2theD]

I don't think you would touch this one now.  What a day. I take meds, have good days and very bad days, the work i do on either are worlds apart.   moving house, things everywhere stressed.  I know, lets learn to fix microscopic Ic's on a cam i nothing about, that will help with stress.  anyway.  where we are at.   I lost the new buck converter twice which was like trying to locate MH 370 on a very messy floor. I'm not sending pictures just yet because i am ashamed.  things got hot well i was trying to make sure u6 was down.  well i was trying to correct D5 that came off u6 blew back off the board lost.    It's been emotional i wont lie.   found, cleaning it up doing something somehow lost it again, found it on iron tip after 10 seconds or so.  It could be fried again.  but it is on, all 4 left pins and bottom left pin all are +5 i think.  All pins register to places there suppose to go with no shorts.  but the resistance is low, not everything is back in the board yet though.

As it stands, I have 3 things i need to put back on the board but a forth thing is lost.   That is a tiny microscopic cap i think.  C87  i can put the stuff back on, will just use an iron, this tiny cap is what i wanted to do first though because it's so small.  There is not chance of finding it.  hoping to nick one out of something. 

I've made a mess of it.  it's had far too much heat. I've melted the plastic for the ribbon cable connector, (Tip bolt on soldering iron) It's all superficial but, a shame and very irritating.   But it's just me, Some days i would breeze this, others i just make a mess.  Really this whole job should not have taken very long, most the time is fixing my own mistakes.   

Thanks Faser

[Fraser]

Do not despair. Everyone is entitled to bad days !

The camera is not toast yet as the power supply section is surprisingly forgiving unless you literally burn a hole in the PCB. Thankfully most of the components are not as fiddly as U6 and U5 ! The missing capacitor is not going to be a problem. The power supply will work fine without it. No need to find another to replace it. Sadly the latest U6 IC sounds like it has been through quite the adventure. That may not bode well for its serviceability. If the resistance across its input is low, its toast. Even with other components missing, it should be well over 100K Ohms.

Part of me wants to help you by offering to fix this unit, but the more sane part of me wants to run away from this camera as I know it will take a lot of time to sort out or end in a "no fix", which will disappoint you. I really do not know what is best for you in this situation. I fear that you will suffer a lot of frustration with this repair and much disappointment if you fail to revive the camera. Sadly this was not the best piece of equipment on which to start learning about hot air rework.

You may just have to put the camera repair "on-hold" until such time as you feel better able to deal with it. I started out practicing hot air rework on inexpensive faulty laptop motherboards bought on ebay for around £4 delivered ! Laptop motherboards provide plenty of small components and IC's to practice on and there is no loss if you cook a few ! I recommend that you try to reassemble the cameras PCB with your soldering iron and if it still does not work. Take a break from it and focus your energies on learning about hot air rework using a suitable scrap PCB. In the very worst case scenario you might need me to look at the camera to determine whether it can actually be repaired. I can produce the essential power supply rails using my lab power supplies. If the faults go deeper than just the power supplies, the unit is likely beyond economic repair. If repair is viable, we would then need to discuss the cost of a repair by me as I can no longer afford to work for free.

Take care of yourself

Fraser

[Nick2theD]

Thanks for everything Fraser, for your patients and knowledge, It’s fixed.   comes on and seems to work fine.  I would have never worked this out on my own.  Thanks again.

I will post more details later.

 

Nick

[Nick2theD]

Fraser you where rite regarding the soler mask and not being fully cured.  Part of the problem was i was trying to mask a pre tined area also.  But i tried again.  only a tiny spot that was the biggest problem.   left the PCB in a draw overnight with a UV torch on it.

After setting U6 down and getting things back on the board.  I could tell it was different.  It was not rite / turning on.   

Checked voltage out of Dc converter and it was 1. something volts.  Checked input voltage and it was low.    Thought it might be the random tiny resister i put in so took it out.  found Q3 mosfet was touching a cap it shouldn’t as well,  sorted these things, still nothing and the voltage was still off.   

Checked orientation of D4 and sure enough i had put it back on the wrong way round.   corrected this and voltage was correct. 

Battery out is 4.1V perfect. 

Only snag at the moment is the battery is at 4.2 volt but the machine thinks it is dead.  Probs just wants a couple of cycles unless what ever charger used killed it.  It’s no biggy anyway it’s been on for 30 mins and seems fine.

[Nick2theD]

[Fraser]

Hi Nick2theD,

This was great news to wake up to this morning  I am so pleased for you. Well done 

Regarding the battery level meter, sadly that will not be a matter of charging and discharging the battery and it is not a faulty Li-Ion cell. The voltage on the cell is sensed by the system and the battery level meter updates as the battery voltage drops. The camera relies upon the protection board on the end of the cell to switch off the supply to the camera when the cell reaches around 2.9V. This is good as it means an indicated discharged battery on the battery guage will not instigate system switch-off, as can happen on other battery gauge designs. This battery gauge issue suggests a broken connection to the ADC input of a system IC that monitors the cell voltage. Either that or damage to the ADC input. Sorry to use both the “Battery” term and “Cell” term in my explanations but the camera instructions will make reference to a battery gauge when, in fact, the camera contains just a single Li-Ion cell. I could use the term “battery” in place of “cell” and only purists would likely complain ! 

If you can live with the Battery Gauge reading “Empty” then it may be best to re-assemble the camera and enjoy it. The battery in these cameras has a capacity of 5000mAh and the camera runs for at least 4 hours on it. I have had a camera run for 9 hours with it switched on and just sitting on the bench.

Another thermal camera saved from the scrap heap. Well done for persevering with the repair despite setbacks 

Please do go on eBay and buy a really cheap laptop motherboard on which to practice hot air rework. A motherboard is quite challenging as it has many PCB track layers and heat is drawn away from some components by the large copper power planes. If you can rework a laptop motherboard with hot air, you are set up for just about any other type of PCB SMD rework I used to remove components, clean the PCB, prep the pads and reinstall, the component. This let me practice both component removal and installation. It is not a problem if you damage a component or the motherboard as it is just for practice and this is why I bought cheap faulty motherboards.
Do not get too adventurous too quickly and try to remove and install large BGA IC’s though. Such large IC’s require a very good knowledge of BGA rework and such tests both the hot air rework station and the skills of its operator. Baby steps is the way to learn hot air rework. Build confidence and understanding of how components, solder and PCB’s behave whilst being reworked with hot air. I also use Infrared rework for large BGA IC’s as I can set a proper temperature profile for the task and I prefer Infrared heating to hot air when working on such large IC’s.

All the best

Fraser

[Nick2theD]

Thank you, I planned on getting into electronics.  hence building a rework station and buying a cam.  I didn't expect to be doing it for the tools i am buying to learn though.   Good stuff.  As far as the battery sensor, I concur it will be fine.    I will look at it when i have a bit more time and space.

getting some scrap boards sounds like a good idea.

Nick

[harm]

Can someone help with Linux u-boot and/or kernel that can run on UTI260B SD card. Mine file system is corrupted and I search for solution.

Any help welcome.
Harm

[Nick2theD]

So, Fraser...  I don't don't suppose you know the values of R163, to the right of TP5000  and C140 to the south of it.    

I couldn't help myself.  I don't even think this was the rite area anyway now.   I think the resistor after u6 sense pin has gone open.  but i'm not messing with that till this is resolved.

Edit, i think R163 is a 4.70 measured in 20k   

Thanks

Nick..

[Fraser]

Nick2theD,

R163 is 4.7K Ohms (4700 Ohms).
C140 is 0.1uF (100nF).

Best Wishes

Fraser

[Nick2theD]

Thanks Fraser.  I'd pretty much decided on 1uf. 

all the best

Nick.

[Fraser]

Nope, you need 0.1uF

Thankfully both components are not critical values so R163 could be anything in the range 4.7K Ohm to 15K Ohm. C140 could be 0.1uF to 0.47uF without issues.

[Nick2theD]

Thanks for this.   I only just read the bit about the values.   I found a 4.6 and it's not booting, I will keep looking for a 4.7 or buy one.
I think i need to put the TP5000 down again though, bad job. 
The TP5000 and surrounding components is just a problem i created.   

I'm not certain, but i think my battery read out might be to do with R99 and R103 that come from the FB pin of U6.     I'm sure one of these i could get a reading off originally.  Now though, they both seem to be open.


Thanks again Fraser.

Nick

[Fraser]

You need a new multimeter or probes !

R99 and R103 are essential for operation of Boost-Buck converter U6. If either were O/C your camera would not be working. The feedback pin cannot be anything to do with the battery gauge as it is a potential divider sample of the regulated +3.3V output of U6 (it does not change with a change in battery voltage).

Battery voltage monitoring must come directly from the battery and not after a regulator or DC-DC converter.

Fraser

[Nick2theD]

Thank you, your not wrong there.  I nearly bought one the other day but, i'm skint so holding off till i get paid again.  I need some decent solder as well.   what do you use?  I use to use draper professional 60-40tin it was the best i've used but it has been discontinued.  Nothing else i have used has come close.

[Fraser]

Where high temperatures are not involved I use Multicore (Loctite) 62/36/2 Tin/Lead/Silver solder LMP.  It is liquid at 180 Celsius and perfect for delicate PCB rework. I would not use it on power resistors though ! For higher temperature situations I use Multicore 60/40 Tin/Lead.
I never use lead free solder as it is truly awful stuff, no matter who makes it !

https://www.farnell.com/datasheets/312832.pdf

Do not confuse Multicore “LMP” solder with the very low melting point solder used for component removal. That specialist solder uses Bismuth and other very low temperature melting point alloys. Very  low melting point solder  is great for specialist desoldering operations, but totally unsuitable for soldering components to PCB’s.

Fraser

[Nick2theD]

Thanks for that. the draper stuff was great, it would clean everything, melt low, take ages for the flux to burn away.  RIP that solder.     I'm not sure what i have done to this.  I am getting 4.1v at the out for the buck, where it should be 3.3v   The cap i put in for a 0.1 at the tp5000 i guessed to be honest, it's so tiny but, that's the only thing.  I've replaced r123 with a 10k.  not sure why it's unhappy.

Edit, found the old cap.  put it in but no change.  will try and redo the tp5000 again.

[Fraser]

TP5000 has absolutely NOTHING to do with the creation of the 3.3V main power rail. That is provided by U6 alone. TP5000 is a battery charger only.

Please walk away from the patient until you work out what you have killed as 4.1V on a 3.3V main power rail is a good way to permanently kill the patient. Either U6 is shorted input to output or the potential divider providing the voltage to the feedback pin has been damaged.

Maybe someone else can step in to help as I need to take a break from this.

Fraser