Jeekul Posted October 19, 2023 Report Share Posted October 19, 2023 (edited) Ok hi from Finland. I'm repairing and modding a Xbox og 1.6 with this samsung psu. The 3.3v and 5v stand-by voltages come and go, i think there is something to do with heat because it worked for a while when i resoldered almost every single solderjoint on the board. I have replaced the 2 big caps and that did fix the original issue of completely dead. I have replaced all the bigger caps on the mobo. Mobo works just fine when the psu gives the power needed. Can someone point me in the right direction? I have been stuck with this for over a month and i'm doing this free for my friend. EDIT: Just tried to measure the psu once again and had no 5v. Then i plugged mobo connector back in and plugged ac plug back on and the f*cking thing works again. Edited October 19, 2023 by Jeekul Quote Link to comment Share on other sites More sharing options...
Bowlsnapper Posted October 19, 2023 Report Share Posted October 19, 2023 @SS_Dave @KaosEngineer You guys have pretty comprehensive PSU knowledge, if I remember correctly. Quote Link to comment Share on other sites More sharing options...
SS_Dave Posted October 19, 2023 Report Share Posted October 19, 2023 14 hours ago, Jeekul said: Ok hi from Finland. I'm repairing and modding a Xbox og 1.6 with this samsung psu. The 3.3v and 5v stand-by voltages come and go, i think there is something to do with heat because it worked for a while when i resoldered almost every single solderjoint on the board. I have replaced the 2 big caps and that did fix the original issue of completely dead. I have replaced all the bigger caps on the mobo. Mobo works just fine when the psu gives the power needed. Can someone point me in the right direction? I have been stuck with this for over a month and i'm doing this free for my friend. EDIT: Just tried to measure the psu once again and had no 5v. Then i plugged mobo connector back in and plugged ac plug back on and the f*cking thing works again. The version 1.6 Xbox power supplies rely on the PowOk signal from the main board to enter standby mode. When you 1st apply the mains the PSU will output a the 5volt for about a second then the mother board sends the PowOk, From there the power supply will continue to run, when the main board sends the PowOn signal the power supply then enable the high current 5 volt and 12 volt supplies to allow the Xbox to boot. Check the SMD transistor next to the Gold clock cap and the Xyclops chip, It's the transistor on the bottom in the pic There is plenty of YouTube vids on replacing this part. Also testing the 1.6 power supply out of the Xbox is not something I recommend as without a load the voltages will read incorrectly. This is a 1.6 supply running with and without a load and the 12 volt supply is only 6.8 volt and the 5 volt is 4.7 then with a load the 12 volt is now 11 volt and the 5 volt is 5.09 volt Cheers SS Dave Soft modding is like masturbating, It gets the job done but it's nothing like the real thing. 1 Quote Link to comment Share on other sites More sharing options...
Jeekul Posted October 23, 2023 Author Report Share Posted October 23, 2023 On 10/20/2023 at 1:13 AM, SS_Dave said: The version 1.6 Xbox power supplies rely on the PowOk signal from the main board to enter standby mode. When you 1st apply the mains the PSU will output a the 5volt for about a second then the mother board sends the PowOk, From there the power supply will continue to run, when the main board sends the PowOn signal the power supply then enable the high current 5 volt and 12 volt supplies to allow the Xbox to boot. Check the SMD transistor next to the Gold clock cap and the Xyclops chip, It's the transistor on the bottom in the pic There is plenty of YouTube vids on replacing this part. Also testing the 1.6 power supply out of the Xbox is not something I recommend as without a load the voltages will read incorrectly. This is a 1.6 supply running with and without a load and the 12 volt supply is only 6.8 volt and the 5 volt is 4.7 then with a load the 12 volt is now 11 volt and the 5 volt is 5.09 volt Cheers SS Dave Soft modding is like masturbating, It gets the job done but it's nothing like the real thing. Sorry for long reply. I measured around the cyclops chip transistors. On the "4,3v" side i have 0,85volts and on the otherside i did not have time to measure because the xbox suddenly came alive again. This is funny. 1 Quote Link to comment Share on other sites More sharing options...
Bowlsnapper Posted October 23, 2023 Report Share Posted October 23, 2023 3 minutes ago, Jeekul said: Sorry for long reply. I measured around the cyclops chip transistors. On the "4,3v" side i have 0,85volts and on the otherside i did not have time to measure because the xbox suddenly came alive again. This is funny. Dude I'm so sorry... Quote Link to comment Share on other sites More sharing options...
Jeekul Posted October 23, 2023 Author Report Share Posted October 23, 2023 8 minutes ago, Bowlsnapper said: Dude I'm so sorry... ??? Quote Link to comment Share on other sites More sharing options...
Bowlsnapper Posted October 23, 2023 Report Share Posted October 23, 2023 36 minutes ago, Jeekul said: ??? That you're having trouble being able to pin this down and address it. Quote Link to comment Share on other sites More sharing options...
Jeekul Posted October 24, 2023 Author Report Share Posted October 24, 2023 On 10/24/2023 at 12:21 AM, Bowlsnapper said: That you're having trouble being able to pin this down and address it. Oh yeah, little slow haha. My english is not the best always. But i need more info, what reading must be off to indicate that/those transistors to be bad? Quote Link to comment Share on other sites More sharing options...
Bowlsnapper Posted October 24, 2023 Report Share Posted October 24, 2023 @SS_Dave @KaosEngineer 1 hour ago, Jeekul said: Oh yeah, little slow haha. My english is not the best always. But i need more info, what reading must be off to indicate that/those transistors to be bad? Quote Link to comment Share on other sites More sharing options...
Jeekul Posted November 13, 2023 Author Report Share Posted November 13, 2023 I ordered cyclops chip transistor from aliexpress. lets see how this goes.. maybe a month when they arrive. Quote Link to comment Share on other sites More sharing options...
ChriZz Posted November 13, 2023 Report Share Posted November 13, 2023 On 10/25/2023 at 12:08 AM, Jeekul said: Oh yeah, little slow haha. My english is not the best always. But i need more info, what reading must be off to indicate that/those transistors to be bad? This? Quote Link to comment Share on other sites More sharing options...
ChriZz Posted November 13, 2023 Report Share Posted November 13, 2023 6 minutes ago, Jeekul said: I ordered cyclops chip transistor from aliexpress. lets see how this goes.. maybe a month when they arrive. Do you have a link to it? It would be new to me that they can be bought individually. Greetings Quote Link to comment Share on other sites More sharing options...
Jeekul Posted November 19, 2023 Author Report Share Posted November 19, 2023 On 11/13/2023 at 8:26 PM, ChriZz said: Do you have a link to it? It would be new to me that they can be bought individually. Greetings I think its 50 pieces from china, for about a whopping 3 dollars. Lol. https://www.aliexpress.com/item/1005005425549024.html?spm=a2g0o.order_list.order_list_main.5.45941802WvP3Hj Quote Link to comment Share on other sites More sharing options...
Jeekul Posted January 22 Author Report Share Posted January 22 (edited) Hello guys, i'm back at it again and i'm starting to think this is actually PSU problem. And that is because i dont have the 5volts on the red wires at stb or anything else on the PSU connector. Only under 0,5v on some of them. Today i (again) took off the PSU from the xbox and just probed it around transistor/mosfet legs and did not find anything that i understand to be a faulty component. The big transistor or mosfet type thing on the low voltage side heatsink has outer legs shorted but i dont know if its a problem. After this probing i put it back to the box and wtf, it powers on again. SO. Im thinking PSU is the problem. Also when i measure the transistor on the side of the xyclops chip, on the left i have 0.33v and on the chip side legs 0v. Please, point me to the right direction or im forced to bail out and this thing probably goes to the bin Edited January 22 by Jeekul Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted January 22 Report Share Posted January 22 3 hours ago, Jeekul said: Hello guys, i'm back at it again and i'm starting to think this is actually PSU problem. And that is because i dont have the 5volts on the red wires at stb or anything else on the PSU connector. Only under 0,5v on some of them. Today i (again) took off the PSU from the xbox and just probed it around transistor/mosfet legs and did not find anything that i understand to be a faulty component. The big transistor or mosfet type thing on the low voltage side heatsink has outer legs shorted but i dont know if its a problem. After this probing i put it back to the box and wtf, it powers on again. SO. Im thinking PSU is the problem. Also when i measure the transistor on the side of the xyclops chip, on the left i have 0.33v and on the chip side legs 0v. Please, point me to the right direction or im forced to bail out and this thing probably goes to the bin Don't throw it away. Someone will be interested in buying it from you for parts. Is it a v1.6 motherboard and PSU transplanted into a v1.0-1.4 case? That will short out the transister Q7C2 by the Xyclops chip since there's another mounting support and grounding tab under the motherboard that touches it between the GPU and encoder chip. A v1.6 case does not have that mounting post/grounding tab present. If so, the grounding tab needs to be bent down so it does not touch the motherboard. 1 Quote Link to comment Share on other sites More sharing options...
MadMartigan Posted January 22 Report Share Posted January 22 I swapped this out on a baord for the exact issue @KaosEngineer is speaking off. It fixed the 1.6 on the first try. I just pulled one from a donor board I had. I also agree that you can sell it or it would make a good donor board If you can't get it fixed. Quote Link to comment Share on other sites More sharing options...
Jeekul Posted January 23 Author Report Share Posted January 23 10 hours ago, KaosEngineer said: Don't throw it away. Someone will be interested in buying it from you for parts. Is it a v1.6 motherboard and PSU transplanted into a v1.0-1.4 case? That will short out the transister Q7C2 by the Xyclops chip since there's another mounting support and grounding tab under the motherboard that touches it between the GPU and encoder chip. A v1.6 case does not have that mounting post/grounding tab present. If so, the grounding tab needs to be bent down so it does not touch the motherboard. Its original board in original case. Power supply wont give almost any voltage on any pin when the fault is on. Its been working since i posted the previous post. Im at a dead end. Quote Link to comment Share on other sites More sharing options...
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