Howard

fixed 4 of these, problem is poor lead-free solder on the LED bar connector failure with heat+age. Resoldering did the trick for me. Here are the directions but does require taking the entire LCD panel apart which is quite fragile.

Just fixed this same issue on my TB Display. Disassembled the entire LCD panel to fix the random blank screen issue (solder LED bar connectors. Always the culprit and fixed about 5 of these now) I thought for sure I had a blown LED and dark patch was from residue. My dark patch had a striped pattern (like rail road ties). Upon full disassembly, found some kind of tape that probably moved with LED generating heat. Peeled off tape that caused the dark patches and used 99% iso to clean off the glue residues. Good as new. Unfortunately, most people won’t be able to fix this. Require a full tear down of the LCD panel. Tape is on the backlight diffuser plexiglass so its way inside. Reasonable chance to destroy the display unless ultra careful and/or experienced. Here is the teardown guide if you really want to attempt this. And if one gets that far, might as well reflow the LED connectors to prevent future blanking out problems common to Apple’s 27” LCDs of this era (iMac 27, Cinema and TB Displays)...

Recently acquired an iPhone 6 with weak 2.4 and 5GHz wifi, Bt, GPS, and cellular signal. After studying the design, there are few ground and antenna contact points that needs attention after drops or just age. Generally, no new parts are necessary (likely just remaking better connection while replacing parts) In my case, just fluffing up a couple of ground contact patch area fixed it. Here is a pic and link to the summary https://drive.google.com/file/d/1lLlRpKd...

Exact same problem and fix. Likely common issue as the backlight flex cable is too long and bent in a way that causes a lifting force on one side of the connector. Mine was tilted at probably 20 degree angle when I pulled the back cover off. Here is a pic One thing to note on failure is every other function key will be extra brighter than rest of the non dim backlight keys. Connection failure probably gave this rail the power of the dim function key rails.

Got a free 27 LED Cinema Display with dark back light (BL) 99% of the time plugging in Display Port. Finally isolated a deterministic sequence that worked for a day. Wife has the same monitor and also not coming on 80% of time when plugging in Display Port. Here is the working sequence. This sequence got the monitor up and working for a couple of hours but since then seem to have more difficulty and backlight just flickers now on the lowest sitting and shutoff at any higher settings. I guess there are thermal related weak solder points likely in the LED strip in the panel. Need (1) Total darkness + a flash light to help see (2) External keyboard for the Mac/Macbook* Preparation Plug in Cinema Display Power Plug in Cinema USB to Mac Plug in Cinema Macbook Magsafe connection (probably don’t need this but might as well get MB ready to close the clamshell later while Cinema Display remains on) Plugin Cinema mini Display Port (mDP) to Mac Use external keyboard (pair it in advance if wireless) F1 key. Click it...

@stillhungry @deepak Fixed one with audio jack ripped out of casing today. There are 5 pads G=Ground=copper color L=Left=light blue R=Right=red M+=Mic+=white inner wire M-=Mic-=dark green outer wire (Other pics that I’ve seen looks black) Here is a pic (not mine) Mine had plastic covering all the solder junctions. Cleaned it off with soldering iron+xacto knife. Careful to not melt off the stud at the red arrow Soldering not so easy. Easy to have a stray strand (if mic + and - touch, then no mic and audio controls) Best have micro soldering equipment. Wires gets twisted upon assembly. and the whole clip has to rotate under the board to get into the body. I thought about removing the board but the flex cable at green arrow gave me caution. Coated the solder junctions with rubber cement (or anything to insulate and secure it that doesn’t expand or shrink)

Have a slightly different problem. 1 out of 4 handset is forever charging even though battery is full. I can put a known full battery (shows full in other handsets) into this one and it will show 1 bar. If the handset charging circuit think battery is not full. All of this without the charging station. The charging station is fine as I can put other good handset in there and battery charing behavior is correct (shows charge complete when full) So obviously if the handset thinks a full battery is not full, then its always charging and generating heat like what I am seeing. Going to probe the circuit board (pic below) for voltage readings. Looks like there are diode on the battery side also. Wondering if others have had this problem. I have 4 handsets and using a known good fully charged battery, I get 2 handsets showing 1/3 bars, 1 showing 2/3 bars, and only 1 handset showing 3/3 bars. Dug a bit deeper into the schematic (didn’t find exact but perhaps close) Battery voltage is fed to the IC (likely pin 58...

Just did this repair on iPhone 6 no boot after water damage, ran fine after, put in rice for awhile, powered on, screen flash squiggly lines and no boot (All done by relatives of a friend haha) Opened it up and took out logic board (need to track screws carefully (get a rubber mat to put them on so they don’t easily get bounced around), if wrong longer screw goes into the hole (particular the lower 3 LCD EMI cover screws) it will damage the circuit board, its called long screw damage if you want to search for that) and found the frequently burnt out capacitor (C5202_RF) on water damaged iPhone 6/6+. Failed cap created a short on the power rails to the wifi chip. Had a cell phone repair shop remove this cap and phone is fully function. Cap doesn’t need to be replaced since its just condition the power source for lower noise for the wifi chip power supply. Not really necessary. I also gave the logic board an alcohol bath for good measures. Didn’t have an ultrasonic cleaner for a more thorough cleaning so 99%...

I know the $25-$30 ones from ebay and tmart.com has a lot of quality problems. Out of the 4 I tried (2 from ebay sellers, 2 from tmart), the 2 from ebay failed within a day or two. One of them has a poorly manufactured connector. The 2 from tmart.com has very poor viewing angles. Color would become psychedelic with a slight tilt. I didn't have problem with a $20 new iPhone 4 LCD from ebay seller 2 years ago. But this recent purchase of $25 iPhone 4S LCDs showed a lot of problems. Certainly, the appearance of the quality seems high with the naked eye. But I could see the subtle defects in the LCD connectors under the magnifying glass that would not provide a proper contact. The LCD viewing angle problems is likely in the materials and/or assembly of the LCD itself. Anyhow, low priced aftermarkets seems to be hit and miss depending on the materials and manufacturing quality of the particular batch.

Likely can skip step 18-28 and all the risks. Battery tape is relatively removable by the following method

- use a tweezer to pull up a corner of each tape. Then use fingers to peel back all the black tab on top of battery

- use 2 hands. Index and thumb on both. Pull about 1/4” with one hand, hold the tension and pull 1/4” with the other hand. Alternate, go slow. Pull out all 4 tape completely. I think the pause after each 1/4” while holding the stretched tape firmly prevents the tape from over stretching to become too thin and break.

- Don’t apply heat, I would guess that makes tape softer and break easier.

Have tried other methods and failed in the past. Pulling too fast (tape will snap) or use a tweezer to twist/roll (sharp edges will cut tape) Anyway, just use index/thumb on both hands and alternately pull slowly

I did do 2 iPhone 8 battery change this way. One removed all tape without breaking. Another broken all 4 tape after about 1/3 pulled so likely some factory assembly differeces.

Following careful methods can mostly preserve the seal and reusable. Won’t be as water tight but probably still pretty good.

Bottom edge is pull up with suction + separating tool. Use small precision scissor to cut any tape that gets overly stretched upon initial opening.

- For the 2 long edges, use an exacto knife to separate the seal from the screen. This keeps the tape on the chassis. Go slow along the long sides. Becareful to avoid scratching the paint on underside of the screen’s edge.

- Top corners have a thick sealed tape. Best to just use separating tool to twist it open.

In summary, top and bottom edge use separating tool. Side long edges can use exacto knife to gradually gently separate the seal from underside of the screen’s edge.

looks like #122A gear available on ebay now. Just search “122A gear”

never found a service manual. Fixed 2. Both had split plastic gear on the motor. One had bulging cap on PSU.

I don't think its hair build-up that makes this wheel difficult to come out. Its the ribbed shaft that is designed to grab onto the last gear. They are slightly bigger than the hole on the housing.

I also used 2 flat blade screw driver 180 degrees apart and that pried it off well.

When inserting back in and putting on the first gear. I had to use a lot of force on a couple of wheels. A socket can be used push it back on.

Used an L shape pick tool to get under the last gear, that pull it off pretty easily.

https://flic.kr/p/2m93Uj2

Update on 6/16/2020 post above.

Got 2 of these, Won’t read some/all discs. Both of them had cracked first gear on the drive motor. Its very high torque so the crack allows the gear shaft to slip and controller gets lost.

Fixed 1 of 2 with a brass gear ordered from Aliexpress (5 gear for $3-$4 shipped) You need 0.4M (modulus) 12T (teeth) 5.5 diameter. Hole diameter 1.93mm. Spec is 122A. This gives about 0.02mm clearance between gear and motor shaft.

I had to use a C-Clamp to fit it on. One slip on a little bit with finger pressure and C-Clamp took it rest of the way. This player was fixed. Other one was very tight and C-Clamp pressure appears to have ruined the motor so becareful. Best to find one that fits on a little with finger pressure.

I also messed with tuning laser power before fixing the gear and lost the reference. So had to readjust the laser. Just increased the resistance on both DVD/CD adjustment screws and gradually decreased it and tested against variety of discs until it played all discs.

Progressive scan uses component video (3 color video connection, red/green/blue) have to get the 3 component video cables connected correctly to get progressive scan working correctly and get to the menu entry to turn it off.

I recall getting the 3 component video cables in the right plug was tricky on this DVD. Don’t remember why, try match the colored plugs between DVD+TV. Might swap around until you get it right if color codes don’t work.

Great tutorial. There is a diagram floating around on the web that has the polarity reversed. I did that first and didn’t work before finding this guide and corrected the wiring. Works great now.

Besides a good fine tip soldering iron and at least magnifying goggles, really good flux makes all the difference on this job since everything is so small. I had some clear liquidy flux (Kester 951? don’t recall, bought long ago to help reflow GPU+SOC BGAs) That worked great as heat instantly flowed to all the right places. Necessary with tiny solder points and rework wire.

Looks like have to attempt this. Have done fairly fine soldering before but maybe nothing this small. What size jumper to use? 0.1mm or 0.02mm?