Re: Macbook A1706 EFI removal
I tried flashing this just now. Same result. It comes with the recovery screen, when I say install macOs Sierra, it thinks for a minute and says "recovery server could not be contacted". Wish there was way to debug this rather than guess. I also had a USB boot that my wife says she had created onetime. Not sure if that would work.
keats11
Senior Member
Last Activity: 04-14-2024, 05:05 PM
Joined: 11-08-2012
Location: Northborough, MA
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Re: Macbook A1706 EFI removal
Serial: C02W56SZHV2L
Board: 820-00239
Attached BIOS (unmodified)...Leave a comment:
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Macbook A1706 EFI removal
I have a macbook A7106 model with an EFI lock on it. I am resonably good at micro soldering, so I removed the BIOS chip and removed the "password section" which is the block of code following the "$SVS" token. There are two such instances in the BIOS. More specifically between addresses
:a) 15B050 -> 15B850 b) 15D050 -> 168FF0. After putting the updated BIOS back, I get a folder with "?". Tried doing MacOS recovery when it says "Recovery Server Could not be Contacted". I did this like 25 times so I know it doesn't work. I have Wifi and also... -
T2 Macbook MDM Unlock by S/N change.
I was hoping someone could point me to a tutorial on MDM unlock. Basically, I picked up a Macbook (A1989) from someone which did not have OS installed. The guy said it started software update and but did not finish. Long story short, the touchbar on this device has some kind of a short, so after unplugging it, I was able to install the OS on it, when I found out that it is also MDM locked by his company. I tried changing the serial number on the ROM by only changing a couple of digits of the original serial number. Now after installing the ROM back, the Macbook appears dead = DFU mode. When I... -
Re: Samsung PN60E7000ffxza no VS_ON
I already tried replacing the Y-main but also before doing that tried changing that cap. But this problem that I am describing doesn't have anything to with Y-sustain firing up. The VS voltage never gets generated to begin with to activate the Ymain.Leave a comment:
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Samsung PN60E7000ffxza no VS_ON
Hi guys, looking for a little help here. I picked up this Samsung TV PN60E7000 in the winter time, guy said it used to intermittently turn on but that it stopped turning on altogether. I brought it home and left it in the cold sunroom for the winter, and one time when it was cold, it turned on and displayed a picture. Now that spring has arrived and I decided to try and fix it. Long story short, at this point I have replaced the main board, logic board, X and Y sustain boards with no success. The PSU itself blew last night and I was able to fix it by changing the QS802/804 mosfets (which seem... -
Re: Samsung UN50H6201 panel problem, half screen
I had a similar TV (model UN50H6203), uses the same Tcon board (and hence the same panel). Same issue, no video with backlight on power on. In my case the right half of the screen had the fault. I took the tcon out and looked at the multiple traces that run to the panel on the Tcon board. All of them have a reisistor in series before they hit the pins on the connector to the flat cable. I removed the first resistor corresponding to the corner of the TV (In this case right corner) and installed it. Vola, TV fired up with a picture...Leave a comment:
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Re: Samsung HP-s5053 No Power,Standby light,NOThing
I had a HP-S5053 with no stand by. When I measured the standby voltage it was very low and fluctuated between 1-1.5V. After doing some mind numbing analysis, tracked it down to a blown thermistor on the power board. Hopefully it helps someone here.Leave a comment:
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Re: Samsung Plasma HP-S5053 half screen picture
Finally fixed this problem. The lower half being dark was due to a bad upper buffer. Hopefully this will help someone on here....Leave a comment:
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Re: Samsung Plasma HP-S5053 half screen picture
Tried another Ysus board. No change in behaviour. I even tried repairing the original lower buffer board by installing two buffer ICs I pulled from another board. No change either. (Due to shorted capacitor on this buffer board from heat , soldering etc, I seem to have shorted the replacement Ysus board.). But I do have the old Ysus board which works fine, so I removed the cap and tried the old Ysus/old_upper/old_repaired_lower_buffer combo,, now the lower half is still black. I think this may be a upper Y buffer problem. Going to...Leave a comment:
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Re: Samsung Plasma HP-S5053 half screen picture
Just to fill more details. Now, when I turn on the TV with the first buffer board I had bought online, the blue bands come on for a second, clears up so that whole screen now looks evenly blue, then the lower half just goes dark. I have attached pictures of the three stages below. I think this may be a Y board fault, but not sure what.....Leave a comment:
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Samsung Plasma HP-S5053 half screen picture
I have this Samsung plasma HP-S5053 that I picked up online. It had no picture but had sound. Opened it and discovered several bubbled/shorted buffer ICs on the buttom buffer board, so ordered one online. Upon installing it, the TV came on, but the bottom half had uneven bands of brightness. It was as though there were differing bands of contrast for the bottom half. Thinking this is surely a lower buffer board problem, ordered yet another lower buffer board and installed it. This time the picture looked even and normal, alas only for 5 minutes. Now the lower half has no picture at all. Looks... -
Re: Panasonic Plasma weird colors, screen pulsing
A little more update on this problem. As luck would have it, someone in my town was selling this very same tv in fully working condition, so I bought it for the purpose of swapping boards to isolate this problem. To my surprise the A board (main board) seems to be the problem. Installing the problem A board in the known good tv recreated the color distortion and Vsus test issues. No idea what could be causing this, at least I won't be engaged in a wild goose chase here.Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
I made a video of the TV problem, can be seen here:
[url]https://youtu.be/3SSyoCW5XTw[/url]Re: Panasonic Plasma weird colors, s...yoCW5XTw[/url]Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
The Vsus voltage as measured by one of my multi-meters jumps around in the 140-180 range. It varies a little bit ( I think it increases), in the custom mode). Out of curiosity I attached an older multimeter in parallel, and the Vsus read more stably on that one, at about 188 volts. Not sure if the older multimeter does a better average than this other one. Did I mention that in the service mode, if I try the "Vsus test", which is supposed to produce a white screen, instead produces a flickering screen, almost as though...Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
Not sure anyone is paying attention here, but looking in the service menu, I see that the last 3 blink codes had been 8,6,6 and the first 2 had been 6 and 6. So I wonder if the blink code of 8 has anything to do with what is happening with the colors. According to Panasonic this is related to SS FPC detect. Does anyone know what that stands for?Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
I take that back, the problem still exists if I set the picture settings to "standard". It works fine in "Vivid", "Cinema" etc. No idea what is causing this. At this point I dont think it is a VSUS or SC board issue, as the behavior of the SC board should not change based on the software picture settings. May be worth trying an software update? But this thing needs a SD card.. sucks..Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
I thought this could be a Vsus problem. The measures Vsus was 189 volts when it first fired up and drops to 174 once the screen comes on. There were no labels on the screen stating what the Vsus value should be, but the service manual seems to suggest a value of 198. I increased the voltage slightly and now the picture looks good in all different picture modes. My guess is that the guy who sold it to me played with the Vsus settings trying to get what was a SC board issue to work, and lowered it to compensate for some weak component...Leave a comment:
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Re: Panasonic Plasma weird colors, screen pulsing
Its a TC-P50C2. I noticed today that if I set the picture settings in the menu to be "Standard", it does the flickering and display poor color. However, if I set it to say "Cinema" or "Vivid", it looks good (no color distortions). Also, although unrelated, there is a faint greenish line across the screen right at the middle, several pixels wide. It is probably related to aging buffers, but I thought I'll mention it here. So really confused.Leave a comment:
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Panasonic Plasma weird colors, screen pulsing
I picked up this TV online, without knowing that it had problems. When I brought it home, it showed weird colors on poweron but it cleared up after say 5 minutes of running. I removed the SC (Ysus) board to inspect it up close, found nothing shorted or tampered with, so I put it back in, except I didn't put all the grounding screws. Upon power on, something blew on the SC board and gave me 6 blinks. Pulled it again, and upon examining up close, saw Q621, & Q661 shorted. Also IC773 (I think is an inverter) was shorted vdd/gnd. Ordered these parts from China and replaced them today, now the...
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