Disassembling LK-7900

Jimbo

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Nice work.

I used to work in a manufacturing factory here in the uk and that lens should be fixed into place at the focusing point not half way along the production line.

Also any chance of you posting a video sample with the new adjustment?
 

Jaguar

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Any updates here? Mine's got terrible focus too :<
 

MrDerrickC

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Big thank you for the photos of how the unit is put together. I just attempted to fix the focus on mine as number plates were unreadable and did not want to waste money sending it back for a warranty job.

Just adjusted the focus and it is now perfect! I bought my 7900 a couple of weeks ago and the glue that held the thread of the lens in was a hot glue type fixing, so was a heck easier to remove.
 

Jazzist

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I probably should have done that too, been without my camera (my only dash cam) for a month now.
 

Jaguar

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It was pretty easy to take apart, mine's much better now, with a slight clockwise nudge.
 

johnf

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I ordered and received an LK-7700 (ebay, Greensum, $130). It took all of 4 days to arrive, very impressively fast shipping. Its focus is very acceptable even if not perfect.

So, I finally got around to disassembly of my LK-7500 which had horrible focus - a spot on the windshield a few inches from the lens was in perfect focus but everything at normal distance was very soft. I bought it on ebay from a seller who promptly disappeared, and Chrontech (sp?) wouldn't help, after many sample stills / videos to them they said it was 'within tolerance'. It was really quite unusable.

Disassembly was quite easy, easier than the 7900 early in the thread.
- unscrew and remove the mount / GPS module.
- remove 2 phillips screws from the rear.
- unsnap / remove the rear cover
- remove the 2 side buttons and the slide power switch so they don't get lost.
- remove 2 phillips screws holding the PCB, pry up and remove the PCB.
- remove 2 phillips screws holding down the lens / sensor assembly from front cover, remove assembly.
- do what you have to do to loosen the lens. In my case, scraped a bit of the locking compound loose from the threads that I could see, secured the rectangular sensor base in an 18mm open end wrench. Wrapped electrical tape around the lens. Used a pliers to break loose the lens threads - it was tight! But after that, the lens could be screwed in or out by finger pressure.

Focusing - used a small 12v battery with a female cig lighter adapter hooked to it for power. Used the AV cable that came with my 7700 to hook to a TV in the kitchen. Keep in mind it is a VGA interface, so resolution is not great, but good enough for focusing. I had marked the lens position using a fine scratch mark before loosening, so I returned it to original just to check. Using a business card to focus on, I moved it about and sure enough, it focused at 3-4 inches - way too close, and anything beyond 6 feet was out of focus. I turned the lens and focused on a chair about 8 feet away. Took everything out in the back yard, moved the camera around and found that everything from about 4 feet to infinity looked to be in good focus. Put in the SD card and recorded a minute moving the camera around as a double check. Looked good. Put a tiny drop of purple (low strength) locktite on the threads.

- reassembled.

The LK-7500 is now in great focus. I can now read signs, plates, etc. I should have done it sooner rather than wasting time trying to get someone else (like the manufacturer) to fix or replace it. The internal design and build quality is impressively good.

Now that the 7500 works like it should, I did a careful comparison between it and the new 7700, and guess what - the 7700 is slightly out of focus, again focused too close. Not nearly as bad as the 7500 was, and totally usable, just not perfect. Thanks for the help provided by the previous folk in this thread for their help and encouragement.
 

Jazzist

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Really silly that this hadn't been fixed 100% in new models like the 7700. Hope my replacement 7900 is decent, probably should have fixed myself rather than waiting months for the replacement.
 

Jazzist

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Found the problem.
Lukas optical assembly production technician :
 

johnf

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It really is frustrating for a nicely made, well designed camera to have the same flaw seemingly over the entire product line. Do they not pay attention to customer feedback at all, or have someone browse the forums? Just as frustrating is their refusal to admit one of their cameras is actually defective - I spent weeks sending stills and videos (at their request) only to have them say nothing is wrong, no matter how lacking in focus every single pic and vid was. I would love to spend a little time with their head production engineer or QA person, if only to see if they really carry a white cane and wear dark glasses. I'd send 'before' and 'after' clips if I though it would do any good. So frustrating...
 

Ericssh

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I really like the Lukas 7900 for its reliability and features but the image quality on mine seemed rather soft. Replaced it with a DR-500 but now that I've found this excellent post, I took my 7900 apart to refocus the lens and now the picture is sharp even in low light! Makes me wonder did they actually check focus before they ship out.
 

johnichan

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Any body fixed GPS module of Lukas Ace 7900? My gps module is failed and sending back to Korea is more costly than new 70mai camera
 

Leonauto

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[QUOTE = "Джонниан, должность: 509166, участник: 66883"]
Какой-нибудь кузовной GPS-модуль от Lukas Ace 7900? Мой модуль GPS не работает, и отправка обратно в Корею стоит дороже, чем новая камера 70mai
[/ QUOTE]
Вы можете взглянуть на эту тему: https://dashcamtalk.com/forum/threads/help-with-gps-wiring.10338/
Здесь показан модуль GPS, основанный на чипсете U-Blox 6 серии ( чип UBX-G6010-ST ).

Каковы симптомы и когда перестал работать модуль GPS, возможно, пропал контакт в разъемах?

Вы пытались обновить прошивку видеорегистратора? Может быть, это может помочь, прошивка здесь: https://www.lukashd.com/page/sub2_6
- Normal_Firmware_AC37 (56,5 МБ, 일반형 펌웨어 일반 펌웨어 : AC37 [14.12.12]).
(Модули GPS тоже имеют свою прошивку, но это отдельная тема, не связанная с видеорегистраторами)
 
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johnichan

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Thanks forthe response. The reply from Lukas in facebook says its GPS module failure after inspecting the video. As no gps time, all video starts with 2013/11/01 12.00.00 time and records video. No speed display as no gps link. The link above I will check. i am using Lukas AC39 viewer software, hoping that that is the latest.
 
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