Xbox 1.6 dead no power

[nerdbombing]

Edited by moderator: Originally posted in similar thread "Xbox 1.1 dead no power".  Moved  @nerdbombing's post to a new topic thread.

I'm having a similar issue with a 1.6

I took the box completely apart to put it into another shell. The box had worked before, no issues, fully softmodded with an upgraded HDD. I wast just trying to put it into a nicer shell as the one it was in had a cracked corner. After putting it into the new shell, nothing turns on. I thought it may have been the front switch or PSU but I replaced both with known good ones. It simply doesn't react to the power buttons, nothing comes on, no lights, and my visual inspection didn't find anything. What's a good place to start diagnosis from here? (Ebay#2)

Edited July 24, 2022 by nerdbombing
Moved post to a new thread

[KaosEngineer]

Just now, nerdbombing said:

I'm having a similar issue with a 1.6

I took the box completely apart to put it into another shell. The box had worked before, no issues, fully softmodded with an upgraded HDD. I wast just trying to put it into a nicer shell as the one it was in had a cracked corner. After putting it into the new shell, nothing turns on. I thought it may have been the front switch or PSU but I replaced both with known good ones. It simply doesn't react to the power buttons, nothing comes on, no lights, and my visual inspection didn't find anything. What's a good place to start diagnosis from here?

Is tne case you moved the 1.6 motherboard into a 1.6 case or a 1.0-1.4 case?  There's a mounting post/ground strap that can short out traces on the bottom side of the motherboard if it's not a 1.6 case.

[nerdbombing]

6 minutes ago, KaosEngineer said:

Is tne case you moved the 1.6 motherboard into a 1.6 case or a 1.0-1.4 case?  There's a mounting post/ground strap that can short out traces on the bottom side of the motherboard if it's not a 1.6 case.

ah man....yeah, that's exactly what i did....

I don't see any damage under the board where that extra post was touching. What do you think it fried?

I had put everything back into the original case and tried again, but it's still dead.

 

[KaosEngineer]

15 minutes ago, nerdbombing said:

ah man....yeah, that's exactly what i did....

I don't see any damage under the board where that extra post was touching. What do you think it fried?

I had put everything back into the original case and tried again, but it's still dead.

 

The transistor at location Q7C2 - a PNP surface mount transistor.

Replacement part numbers:

• MMBT4403LT1G - Bipolar Transistor - BJT 600mA 40V PNP

or

• MMBT3906LT1G - Bipolar Transistor - BJT 200mA 40V PNP

 I prefer using the 4403 as a replacement because of its higher maximum current rating.

 

@Floydthebarber created a test and replacement tutorial video years ago that is posted on YouTube:

 

[nerdbombing]

1 hour ago, KaosEngineer said:

The transistor at location Q7C2 - a PNP surface mount transistor.

@Floydthebarber created a test and replacement tutorial video years ago that is posted on YouTube:

Can I buy you a beer sometime?? Freakin thank you my friend!

Guess I'll see about getting a new transistor and giving it a shot, it appears within my soldering ability. For the time being, do you know if there are any on a V1.0 or 1.1 have the same part, as I have a "parts" board of those versions....?

[KaosEngineer]

On 7/9/2022 at 12:12 PM, nerdbombing said:

Can I buy you a beer sometime?? Freakin thank you my friend!

Guess I'll see about getting a new transistor and giving it a shot, it appears within my soldering ability.

Before ordering a transistor use a multimeter to measure the transistor's collector voltage level.  The pin on the side by itself.  It should be at a stable voltage level of approximatelly 3.3Vdc.

Also make sure that the v1.6 power supply unit is providing the standby (STB) 5 Vdc voltage level (orange wire) when the console is off and AC power is connected.

Note: I believe the Blue wire's stated STB level is wrong in this figure.  I believe it should be  0V, not 3.3V in the STB column.

[KaosEngineer]

4 hours ago, nerdbombing said:

For the time being, do you know if there are any on a V1.0 or 1.1 have the same part, as I have a "parts" board of those versions....?

v1.0/v1.1 and v1.2-1.4 Xboxes are different.  The power on problem with them is normally caused by a broken trace that carries the power button signal from the front panel button to the System Management Controller (SMC - a PIC processor); however, a problem with the power supply unit (PSU) itself can prevent the console from powering on - cracked and burnt AC power source connector solder joints caused by poor mechanical strain relief, a blown fuse or some other component/components on the PSU is/are dead.

Test for the standby voltage level at the PSU connector on the motherboard.  If present, measure continuity of the trace that carries the power and eject button signals to the SMC.

See: web.archive.org/web/20130309081914/http://diy.sickmods.net/Tutorials/Xbox1/Power-Eject_Pinouts

 

[nerdbombing]

56 minutes ago, KaosEngineer said:

v1.0/v1.1 and v1.2-1.4 Xboxes are different.  The power on problem with them

I was really just trying to see if there are the same transistors I can rob off an older board, cause some components sare the same.

But either way, I check for stand by voltages and not getting any. But I put the psu into another 1.6 i have and it boots up. what am i doing wrong here??? going mad most likely...

[KaosEngineer]

18 hours ago, nerdbombing said:

I was really just trying to see if there are the same transistors I can rob off an older board, cause some components sare the same.

But either way, I check for stand by voltages and not getting any. But I put the psu into another 1.6 i have and it boots up. what am i doing wrong here??? going mad most likely...

No, there's no such transistor on older revisions of the motherboard, only on v1.6s.  (Edit: that may not quite be true, there are a lot of surface mount transistors in other areas on the Xbox motherboards so one of them may also be a PNP MMBT4403LT1G transistor.)

And v1.0/1.1, v1.2-1.4 and v1.6 PSUs can only be swapped/used on consoles within those three different groups of motherboards revisions.

v1.0/1.1 uses an AT-style 1x12 pin connector

v1.2-1.6 all use an ATX-style 2x10 pin connector; however, even though the motherboard's power connectors are the same type do NOT swap PSUs between v1.2-1.4 and v1.6 Xboxes. The voltage rails on some of the pins are different.  

[prtscn]

Check this PDF file.

Xbox_v1.6_Resurrection.pdf

[nerdbombing]

On 7/19/2022 at 1:52 PM, prtscn said:

Check this PDF file

Roger, thanks.

I replaced the component with a new one, but I get 0 vDC there (collector).

I pulled the ATX power connector, and my 5v standby power is reading 3.95vDC on the "orange" wires (and so is my known good PSU)

I checked for 3v standby power and got none at the ATK connector as @KaosEngineer noted.

I tried another 1.6PSU, known working, since I've installed a new transistor. No change, same results.

Seems like power isn't getting to that transistor?

I have continuity from the power pin to R3G6

And from the LPC header pin (ID'd in Kaos' link) to the Xyclopse chip. (as well as all the other traces within the pic from the link Kaos liked to, eject and various traces between the resistors near the power/eject/LED connector) All ohm'd out good

[prtscn]

8 hours ago, nerdbombing said:

Roger, thanks.

I replaced the component with a new one, but I get 0 vDC there (collector).

I pulled the ATX power connector, and my 5v standby power is reading 3.95vDC on the "orange" wires (and so is my known good PSU)

I checked for 3v standby power and got none at the ATK connector as @KaosEngineer noted.

I tried another 1.6PSU, known working, since I've installed a new transistor. No change, same results.

Seems like power isn't getting to that transistor?

I have continuity from the power pin to R3G6

And from the LPC header pin (ID'd in Kaos' link) to the Xyclopse chip. (as well as all the other traces within the pic from the link Kaos liked to, eject and various traces between the resistors near the power/eject/LED connector) All ohm'd out good

You should measure BASE (B) voltage.

[nerdbombing]

4 hours ago, prtscn said:

You should measure BASE (B) voltage.

Thanks!

But nothing there, 0v. My meter reads some small variances around .5-1mV with open probes (you know, that residual, or static that registers on most electronic meters. Or at least it's normal for this meter), and as soon as I touch the base, collector, or emitter, it drops and stays at exactly 0mV (meter will automatically switch to V if it's present over 1vDC, and reverts to mV until it hits at least 1vDC) . I double checked and the meter is on DC.

(Meter is a Southwire 21010N, a meter I use in my professional occupation, and thoroughly trust).

[prtscn]

1 hour ago, nerdbombing said:

Thanks!

But nothing there, 0v. My meter reads some small variances around .5-1mV with open probes (you know, that residual, or static that registers on most electronic meters. Or at least it's normal for this meter), and as soon as I touch the base, collector, or emitter, it drops and stays at exactly 0mV (meter will automatically switch to V if it's present over 1vDC, and reverts to mV until it hits at least 1vDC) . I double checked and the meter is on DC.

(Meter is a Southwire 21010N, a meter I use in my professional occupation, and thoroughly trust).

check lpc port for 5V standby

https://xboxdevwiki.net/LPC_Debug_Port

Edited July 23, 2022 by prtscn

[nerdbombing]

3 hours ago, prtscn said:

check lpc port for 5V standby

while i'm in there, and with no PSU connected to mobo: i checked the ground pins (12 & 2), but figured id check others, and i have ground from the following pins: 2, 6, 12, & 15. that's the 5v and 3.3v plus the 2 grounds.... (BTW, I ran that check to make sure I was looking at the LPC in the correct orientation).

when plugged in and AC on, the 5v pin is 0vDC

I pulled the board and looked around for maybe a solder blob or splash that might be bridging something, but I can't see anything like that. Later, when i time, I'll try washing the board again with isopro....

[Prehistoricman]

This issue sounds just like the other dead 1.6 that we have on the forum right now 

 

[nerdbombing]

12 minutes ago, Prehistoricman said:

This issue sounds just like the other dead 1.6 that we have on the forum right now 

Thanks for sharing. I had a read through and I think I'll try @SS_Dave's last comment about pulling out the AC plug for at least a minute and see if I get that quick spike of voltage before it drops out due to his explanation.

But there's some difference between @Cytraz's problem and mine... actually I'm not sure. I'm gonna go through all the suggestions there and see how that goes.

I was also curious, so i ohm'd out the emitter, it's grounded. Not sure what it should be, but i checked the base and collector and they did not trigger my meter to beep (didn't check actual resistance, just checked for "straight" through continuity).

[prtscn]

9 hours ago, nerdbombing said:

while i'm in there, and with no PSU connected to mobo: i checked the ground pins (12 & 2), but figured id check others, and i have ground from the following pins: 2, 6, 12, & 15. that's the 5v and 3.3v plus the 2 grounds.... (BTW, I ran that check to make sure I was looking at the LPC in the correct orientation).

when plugged in and AC on, the 5v pin is 0vDC

I pulled the board and looked around for maybe a solder blob or splash that might be bridging something, but I can't see anything like that. Later, when i time, I'll try washing the board again with isopro....

Could be a blown fuse, not sure if any on the board. Check Power rails for short. Red probe to 5V (etc.), black probe to ground, when using beep mode and resistance mode for good measure, high resistance is good.

So we can conclude that the board is having power issue.

[nerdbombing]

After re-reading:

My checklist looks like this:

1. Check red, yellow and orange (12v and 5v) at PSU; plugged in and unplugged.

ATX unplugged from mobo: Red is 100mv, Yellow is 9mv, Orange is 4v at the unplugged ATX connector. All are 0v when plugged into mobo, with and without power/eject switches connected.

2.Check pin #4 on LPC; power/eject switch plugged in, unplugged, and button pushed.

0v for all conditions listed.

3. Unplug power/eject, recheck all the above.

No changes.

4.R3G6, R3G4 and Pin2 of power/eject connector, additionally R3G3 and R3G5 to pin4 of said connector for continuity and voltage.

0v to all 8 points near resistors, same for pins 2 & 4 of power/eject switch connector on mobo (that's the bottom left most 2 pins from front of unit). Continuity between pin 2 and right sides of G6 and G4. Continuity with pin 4 and G3 and G5 right side of resistors.

5.Check IC and inductor per @Prehistoricman's suggestions.

0v with and without power/eject switch connected as well as with power button depressed.

6. Double check Q7C2, collector.

0V with power/eject switches connected, disconnected and power button depressed.

7.Check ATX connector's orange and blue, unplugging for min 60sec before checks. Looking for quick spikes per @SS_Dave's suggestions.

Quick rise to 300mv max but falls quickly to 0v on Orange. Blue (powOK) goes to 10mv, but falls to 0. I also checked the PowOn (white) and have 19mv steady.

 

 

 

[Prehistoricman]

Yep with the reading at the inductor, this really sounds the same as the other topic. I just don't know where the 5V from the power connector goes and gets stopped. 

[nerdbombing]

16 minutes ago, Prehistoricman said:

Yep with the reading at the inductor, this really sounds the same as the other topic. I just don't know where the 5V from the power connector goes and gets stopped. 

I think one of the main differences between the other topic and this one is that I know what caused it: switching a 1.6 board into a 1.1 case, allowing the ground lug to short something.....

[SS_Dave]

I just tested a random 1.6 here that has a Delta PSU 

The orange wire all have 5 volt as long as the AC is connected.

With the 20 pin plug disconnected I get 0.1 volt on the PowOk  and it has 5 volt on the orange wires.

 

It's looking like you may have a dead PSU..

 

Cheers

SS Dave

Soft modding is like masturbating, It gets the job done but it's nothing like the real thing.

[Prehistoricman]

@nerdbombing Are you sure you read 4V on the orange wires and not something closer to 5V?

[nerdbombing]

16 hours ago, SS_Dave said:

It's looking like you may have a dead PSU..

16 hours ago, Prehistoricman said:

Are you sure you read 4V on the orange wires and not something closer to 5V?

PSU is good, voltage is reading the same on both PSU's (not sure if I showed the second, but it is the same as the first) https://youtu.be/oX9MhvWFRIs

I'll see about setting a tripod so I can go through a smoother process in the future, with my video making. I'll gladly film anything or suggestions that will help you to help me. I just went through some random checks since i didn't have a good script, i can go back and clean up the tests if needed. I also messed up filming by vertically.... I'll fix that too.

I know I miss identify various cables, ports, etc., but I tried to film the correct ones, so go by the video, not my narration in those cases. I sped up the playback speed, but I found I needed to speed it up in youtube as well~maybe i have a hard time watching myself so I try to make it go by quick lol

 

[Prehistoricman]

6 hours ago, nerdbombing said:

PSU is good, voltage is reading the same on both PSU's (not sure if I showed the second, but it is the same as the first) https://youtu.be/oX9MhvWFRIs

That's a very useful video. I see there is no voltage present in the Xbox as long as the power connector is plugged in. That's going to be some over-current detection shutting off the power supply. Basically you have something short-circuited on the board. The expert repair man at NorthridgeFix always diagnoses shorts by injecting voltage with a power supply and seeing what gets hot. I don't suppose you have a thermal camera?