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1.6 Dead As a Door Nail.


bigted1977
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Hi, I have a 1.6 crystal, I'm the first to open it up, it has no life when the buttons are pressed, so far I have,

Tested the power supply, and the power when the power button is pressed and held. I'm getting all the correct voltage when standby and when the power button is held, it tells me the power supply is doing its thing.

The only one that is slightly out is the 12 line at stand by it shows about 0.34, when plugged on to the board but 0 when removed and just the plug probed.

It had the 5 capacitors all leaking and bulging around the power socket, so I incorrectly thought that would be the problem and changed those for some panasonic units.

Again this didn't sort the problem.

I checked the transistor at Q7C2 and was getting 3.36 volts on the collector, but to prove a point I removed it from the circuit and put it on the tester independently  it showed as a working pnp transistor. (I have ordered some new ones as it off the board so might as well replace it.)

I have read that the clock cap can be replaced with a capacitor but now cant find the correct value, as a fault clock cap can prevent power up?? plus it looks like i may have damaged this one with the heat gun, could just be the outer paint coating scorcher on closer examination though, been unplugged a while and still showing 1.66 volts.

The traces from the power/eject socket are good going up to the xyololops chip. cant see any corrosion on the underside of the board either.

so that's where I am with it at the moment any suggestions on what to test next.

I have a 1.4 board and ps that i can fit into this lovely case but would like to try and fix this one first.

The board dosen't look dead flush where the cpu sit on it slight warpage of the board with the weight of the heat sink pushing down, this may be normal though.

Thanks

Ted

20190801_190547.jpg

IMG_-hoiy8u.jpg

IMG_e6e0gi.jpg

Edited by bigted1977
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The clock cap is a 1F super cap rated at 2.5Vdc.  Brand: nichicon 

The 12Vdc line from the Power Supply Unit  (PSU) reads 0.34Vdc or 12 - 0.34Vdc ~= 11.66Vdc.

With no load attached to the 12Vdc line, the PSU's protection circuitry may automatically switch that supply level off - thus the 0Vdc reading when only the multimeter is connected to it.

You measure 5Vdc at the standby pin on the motherboard's power connector.

psu16delta.gif.ec7fddf86a60d6de23d8d8530ec4161c.gif

I think this graphic is in error for the Blue wire (PowOK) in STB (standby) mode. It should read 0Vdc, not 3.3Vdc.

The v1.6 Xbox uses 5Vdc for the standby supply level, unlike all the previous vesion PSUs which use 3.3Vdc.

 

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On 8/4/2019 at 5:11 PM, KaosEngineer said:

The clock cap is a 1F super cap rated at 2.5Vdc.  Brand: nichicon 

The 12Vdc line from the Power Supply Unit  (PSU) reads 0.34Vdc or 12 - 0.34Vdc ~= 11.66Vdc.

With no load attached to the 12Vdc line, the PSU's protection circuitry may automatically switch that supply level off - thus the 0Vdc reading when only the multimeter is connected to it.

You measure 5Vdc at the standby pin on the motherboard's power connector.

psu16delta.gif.ec7fddf86a60d6de23d8d8530ec4161c.gif

I think this graphic is in error for the Blue wire (PowOK) in STB (standby) mode. It should read 0Vdc, not 3.3Vdc.

The v1.6 Xbox uses 5Vdc for the standby supply level, unlike all the previous vesion PSUs which use 3.3Vdc.

 

The blue on mine 3.3 at standby

orange 5 at standby

and 0.46 on yellow at standby

 

Swapped out the power supply for another 1.6 and still no boot.

Edited by bigted1977
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18 hours ago, bigted1977 said:

The blue on mine 3.3 at standby

orange 5 at standby

and 0.46 on yellow at standby

 

Swapped out the power supply for another 1.6 and still no boot.

Thanks for measuring the voltage levels. 

I guess part of the system does still have 3.3Vdc in standby (while off). MS changed the voltage supply level that runs to pin 6 of the LPC debug port.  Pre-1.6 consoles have a switched 5Vdc level while 1.6 versions have a constant 5Vdc present as long as AC power is connected.

The 3.3Vdc must still run to the clock circuitry as it did in previous versions of the console.  I need to see if I can track down (someday really soon now :) ) where the 3.3Vdc blue wire runs to on the motherboard.

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And, the SMD transistor (Q7C2) between the clock cap and Xyclops chip had 3.3Vdc present on the collector (pin labeled C below).

          ____
    B --|      |
          |      |-- C
    E --|      |
          ------

Updated: Added a better picture of the transistor from the ONSemiconductor datasheet.1670186182_OnSemiconductorMMBT4403LT1.JPG.cf71a1120e8ec2a2ee46bc96df3bcf33.JPG 

They are one manufacturer of this part - MMBT4403LT1 (part labeling 2T).  Another Xbox Repair Manual states that the replacement part is an MMBT3906LT1 (part labeling 2A).

Odd, not sure why it would not power on.

Next, check the voltage level present at the PowOn control line of the motherboard PSU connector.

Does it go high (3.3 or 5Vdc) when you press the power button and is low (0Vdc) when not pressed?

 

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I've been doing some googling, this is quite a common problem on the 1.6s according to the amount of people who have posted with this issue.

 

Could it be a bios issue, corrupt or missing after a long period off no power ?

I suppose the way to test it would be with a mod chip, but its been so long since i used to mod these, is there one that actually take the place of the bios ?

 

Ted

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Sounds strange but as a ver 1.6 wont boot with out a Clock cap have you checked to see if there is voltage at the cap.?

There are plenty of  MOD chips cheap on flebay that will work, you will need to do a LCP conector rebuild which I dont think sould not be an issue for you.

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  • 1 year later...

Had sime free time tonight, so pulled this old board down and  made some progress, re flowed the mcpx. We now boot to flubber. It hangs in flubber with evo m8 1.6. Nut made some progress, it's not dead. 

 

Not got a dvd drive handy so with chip removed give error 12.

 

Might help anybody else who is struggling.

 

Ted 

 

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Yeah I guessed that, was just pumped i got it to boot at all, Stuck evox m8 1.6 on there, edited with evtool. chucked my HD from another xbox to test. 

All good so far.

Cleaned up old flux and renewed thermal pasted on gpu and cpu.

thanks for the help

Ted

Edited by bigted1977
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  • 2 months later...
On 3/15/2021 at 5:24 PM, bigted1977 said:

Had sime free time tonight, so pulled this old board down and  made some progress, re flowed the mcpx. We now boot to flubber. It hangs in flubber with evo m8 1.6. Nut made some progress, it's not dead. 

 

Not got a dvd drive handy so with chip removed give error 12.

 

Might help anybody else who is struggling.

 

Ted 

 

Hello friend, how did you solve the problem? I am not clear about how you solved the problem, could you explain to me? I also have an xbox 1.6 that does not turn on, I already changed the MMBT4403LT1 transistor but it still does not turn on. Thanks

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  • 2 years later...

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