writing on the back of my battery cover

[kq702]

Hi, I have a few motorola droid razr phones and I noticed on the back of the battery cover on the lower right hand side each of them has hand written markings. One of them has "L7" written, another has "L 14" written, and another has "L 15" hand written with a black marker. I am just curious as to what the L numbers are used for? I also see another marking (made with the same marker) about an inch and a half to the left of the L number. Two of the three back covers that I have, show marks in this area. The third one is blank in that area. See photos below

So what do the L numbers represent?

 

[jpcalhoun]

Not sure you'll get many responses here because most users haven't been brazen enough to take the back cover off their phone thus voiding the warranty etc. I'll offer a SWAG and say those letters/numbers are part of a manufacturing process that identifies assemblers or date/time/batch/location that the phone was assembled...just a guess.

 

[FoxKat]

Not sure you'll get many responses here because most users haven't been brazen enough to take the back cover off their phone thus voiding the warranty etc. I'll offer a SWAG and say those letters/numbers are part of a manufacturing process that identifies assemblers or date/time/batch/location that the phone was assembled...just a guess.

And likely a very good guess! During the manufacturing process, [virtually all parts, even] small parts such as these go through several processes from the intial molding of the plastic surround to de-burring, drilling and other additional manufacturing processes, to adhering of the Kevlar, and to final surface preparations before assembly. Each of these processes is often checked by either the individual running the equipment or a QC personnel somewhere further down the assembly line.

As each part is further "dressed" such as to remove small burrs or other extra material from the molding process, often the person running the equipment will mark it to assure someone further down the line that it passes their visual exam. You are likely to get no benefit from knowing those marks other than what's been explained.

I will remind you however that by opening the case you have voided your warranty, you have introduced dust and other contaminants into the interior of the phone, you may have damaged the airtight seal that exists around the main microphone and also around the speaker and noise cancelling microphone to create a small hollow chamber (similar to an acoustically sealed speaker cabinet), and enhance audio quality. You could also have damaged the rear-facing camera which is a highly delicate instrument due to its miniscule size and critical alignments.

You may have damaged or compromised the lamination benefits of the double-sided tape that holds the back and battery together - reducing the ability to withstand flexing, and you may also have damaged the water-resistant surface applications that exist to protect the phone's circuitry. There are also very delicate ribbon cables (including the one which connects the battery), and snap fit connectors throughout which can only withstand very minor movement or pressures, and even the slightest touch could render one of them unserviceable.

I suggest you put the covers back on and use the phones as intended, and resist digging further into them as you may render them useless.

 

[Kimo91]

I'm guessing manufacturing stamps and quality assurance stamps for the whole assembly process but that's just a educated guess

Sent from the Sith powered and rooted Motor DROID RAZR

 

[FoxKat]

I'm guessing manufacturing stamps and quality assurance stamps for the whole assembly process but that's just a educated guess

Sent from the Sith powered and rooted Motor DROID RAZR

Correct, and I didn't mean to imply by my statement above that only the "small parts" go through such scrutiny...

 

[kq702]

yeah I know they have date stamps marked on the plastics (they were engraved with the machine molds). If you look at the photo i attached in my original post you can see one of the markings is an 11 with a circle and half of the circles have dots in them- I know that represents 2011 and half the marks means prob manufactured in June of 2011. The 1E you can see in the impression shows the mold number and posably the machine number (not 100% sure on the machine number but I am pretty sure) but i do know for sure one is the mold number. So given that that is all the important info, I was just curious as to why the L numbers.

PS- the back door is nothing to open, I have already taken one of them completley apart (up to the LCD) because the LCD is a real chalange to open up! Not even sure if its posable.

I am also a cell phone tech, so I do know what I am doing but thanks for the advise.

Also wanted to say about the microphone padding I talked about in my original post was actually installed on all three units, not just one like i originally said. On the two that i thought were missing the padding I found it on the microphone area on the back of the unit on the main housing. Once I snap the back cover back in it will once again have its tight seal arround the mic.

 

[FoxKat]

yeah I know they have date stamps marked on the plastics (they were engraved with the machine molds). If you look at the photo i attached in my original post you can see one of the markings is an 11 with a circle and half of the circles have dots in them- I know that represents 2011 and half the marks means prob manufactured in June of 2011. The 1E you can see in the impression shows the mold number and posably the machine number (not 100% sure on the machine number but I am pretty sure) but i do know for sure one is the mold number. So given that that is all the important info, I was just curious as to why the L numbers.

PS- the back door is nothing to open, I have already taken one of them completley apart (up to the LCD) because the LCD is a real chalange to open up! Not even sure if its posable.

I am also a cell phone tech, so I do know what I am doing but thanks for the advise.

Also wanted to say about the microphone padding I talked about in my original post was actually installed on all three units, not just one like i originally said. On the two that i thought were missing the padding I found it on the microphone area on the back of the unit on the main housing. Once I snap the back cover back in it will once again have its tight seal arround the mic.

OK, glad to know I am communicating with someone who is knowledgeable and experienced when they are poking around inside there. The foam grommets are very delicate as you know, and I just wanted to be sure they weren't damaged, but you already know that. As for where they are applied, it really doesn't matter if they are affixed to the cover side or the component side, since once squeezed and held together by the cover clips, there will be the desired air-tight seal.

The SAMOLED (not LCD) display is affixed to the digitizer by laminate adhesive. This is essentially double-sided tape. The two can be separated but to keep dust and debris out they have that perimeter seal. This also adds strength and resistance to flexing similar to Plywood. I feel it's far better if you should ever have to replace one or the other, to do both as one unit to maintain that dust-free integrity.

The markings are certainly interesting and you seem much like myself - always curious. :biggrin: I can find the most mundane information entertaining at times, so I can understand the desire to know what they all mean. If you do "crack the code" let me know!

Take care.