I have just got in a MacBook Pro A2338 which was initially displaying the Apple logo followed by an explanation mark in a circle as described here:- https://support.apple.com/en-gb/102164.
After some error messages attempting to revive and restore the machine via DFU mode i have finally got the machine revived however now the issue seems to be when attempting to install macOS Sequoia via a bootable USB installer or via macOS recovery the machine just keeps freezing and restarting before the installation is complete, usually the installation has just started or is mid way trough before...
Simplebeans
Senior Member
Last Activity: 08-11-2025, 03:45 PM
Joined: 09-27-2021
Location: Leicester
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MacBook Pro A2338 keeps restarting when attempting to install macOS
Last edited by Simplebeans; 08-10-2025, 11:14 AM. -
Perfect!, tried this EPROM dump and the television is now swiching on and working. Just out of interest what programmer do you currently use?, i have a RT809F ISP Serial Programmer....Last edited by Simplebeans; 07-28-2025, 06:39 AM. -
Just got the faulty EPROM dump, please see attached....Leave a comment:
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The circuit board is a T.MSD309.B66B. Do you still need the EPROM dump or is one available already?...Last edited by Simplebeans; 07-27-2025, 07:15 AM.Leave a comment:
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Blaupunkt 236/2071-GB-3B-HKDUP-UK stays in standby
I am currently attempting to repair this television.
Currently the television stays in standby mode (red light on the television) even after attempting to switch it on via the remote control or controls on the television itself. I have opened the television up and there was a electrolytic capacitor that looked bad therefore replaced this however this has made no difference and the same issue still persists.
I am now thinking that this could be a EPROM issue? If yes, i have not yet been able to locate a EPROM dump for this make and model of television, if anyone can help... -
Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable
Yes and whenever you are ready let me know and ill be glad to help....Leave a comment:
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Re: 820-01041 stuck on 5volt 220mah
Your not getting PP1V1_UPC_XB_LDO_BMC on all 4 CD3215's? Did you check the grounding capacitors on all 4 lines?...Last edited by Simplebeans; 02-02-2023, 02:12 PM.Leave a comment:
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Re: MacBook A1466 820-165-A No power Missing PM_SLP_S4_L
Did you check the signals around the SPI rom circuit to make sure there all ok? i.e the SPI_MLB_CS_L etc?...Leave a comment:
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Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable
Hi wnt2fx can you post all the voltage readings for the 4 LDO rails on all four of the CD3215's, So that's the U3100, U3200, UB300 and UB400. If you need any help with what signals you need to measure for this let me know.
And are you using a Genuine Apple 61W USB-C Power Adapter with the USB-C Charge Cable?...Last edited by Simplebeans; 09-22-2022, 12:43 PM.Leave a comment:
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Re: ASUS ViviBook X512F no power
I appreciate your input but really not sure what you mean? The status of the machine has not changed (apart from replacing a mosfet), the voltage measurements are all the same as when i started this thread. The only inductor that has a voltage reading is the one right near the charger IC. All the other inductors are showing 0V....Last edited by Simplebeans; 08-11-2022, 03:55 AM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Ok 2nd mosfet issue now resolved, resistance readings are good now. Still no power....Leave a comment:
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Re: ASUS ViviBook X512F no power
Yes i just measured and the current sense resistor which does have a measurement of 19V on both sides of it, PIN's #1 and #2 respectively.
I have just noticed something interesting that i may not have noticed previously. So the first dc in mosfet (M3056M) when measuring resistance from S-G: i get 97KΩ however the second mosfet (M3054M) S-G measures 2.6KΩ. The interesting thing is all the other mosfets in the circuit after these mosfets, that i have mesured so far are showing all at around a 7.3KΩ measurement...Last edited by Simplebeans; 08-04-2022, 12:58 PM.Leave a comment:
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Re: ASUS ViviBook X512F no power
01) The first mosfet in the dc-in circuit at the drain, source all measure 19V and the gate measures 24V. The power reaches the second mosfet, there at the drain then measures at 19V however no voltages measure on the source/gate side of second mosfet.
02) The main current sense resistor i can see, is placed near the first mosfet in the dc-in circuit, the resistance at this resistor (meter is resistance mode 20MΩ), black probe to ground point and red probe to PIN #1/2 @ the resistor measures 3.2MΩ and rising....Last edited by Simplebeans; 08-01-2022, 02:41 PM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Haha thats why its nice working on Macbooks, there is always a schematic(s)....Last edited by Simplebeans; 08-01-2022, 01:54 PM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Hi thanks and appreciate your help on the 0Ω resistor, at least we know what that part is now.
Do you have any schematics for this board at all?...Last edited by Simplebeans; 08-01-2022, 11:29 AM.Leave a comment:
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Re: ASUS ViviBook X512F no power
On the USB tester i can see when i plug into the power it reads 0.00amps. So drawing no current....Leave a comment:
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Re: macbook pro 13 2016-2017 820-00840 stuck on apple logo
What readings do you get on a USB tester during this issue?
I would be inclined to revisit this, when you changed the bios you need to get the machine atleast getting to the apple logo to see if its produces the same error. This way we can rule out the bios....Last edited by Simplebeans; 07-14-2022, 11:54 AM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Yes no power, also when the charger is plugged in there are no lights illuminated....Last edited by Simplebeans; 07-02-2022, 06:05 AM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Ok so replaced the lcd connector, i didn't want to do any further testing until this was done. I have just checked resistance to ground on both coils, below are the readings(multimeter in resistance mode 20KΩ, black probe to ground point and red probe to each side of each of the coils):
5V Coil: 10.82KΩ
3V Coil: 7.89KΩ
Checking the mosfets on the 5V, 3V rails near the coils, both of the rails seems to be getting the 19V at the drain of 1 of the mosfets, nothing on the gate/source....Last edited by Simplebeans; 07-01-2022, 08:05 AM.Leave a comment:
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Re: ASUS ViviBook X512F no power
Thanks so a couple of things i have done so far just to update, i had to remove the LCD connector because when plugging in the charger this was getting hot and upon closer inspection the PINS on the LCD connector on one side were damaged. Checking under the thermal camera to make sure I could see that this one side of the LCD connector was indeed getting hotter. So I have removed and plan on replacing that from a donor board.
As suggested I measured the resistance on both sides of the missing component and this is the readings...Last edited by Simplebeans; 06-27-2022, 12:40 PM.Leave a comment:
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