bigted1977 Posted August 3, 2019 Report Share Posted August 3, 2019 (edited) 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 Edited August 3, 2019 by bigted1977 Added pics Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted August 4, 2019 Report Share Posted August 4, 2019 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. 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. Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted August 4, 2019 Report Share Posted August 4, 2019 Are there any markings on top of the transistor? 2A or 2T Which transistor did you order as a replacement? MMBT3906LT1G or MMBT4403LT1G Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 4, 2019 Author Report Share Posted August 4, 2019 (edited) Thanks for the reply, it's the first one you said 3906lt1g I have ordered. I'll have a look to see if I can make out any numbers. It said 2tz on the top. Thanks Edited August 4, 2019 by bigted1977 Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted August 5, 2019 Report Share Posted August 5, 2019 2T is an MMBT4403LT1G Ic max 600mA 2A is an MMBT3906LT1G Ic max 200mA Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 5, 2019 Author Report Share Posted August 5, 2019 I'll order some more. Thanks for that. Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 9, 2019 Author Report Share Posted August 9, 2019 new one fitted (MMBT4403LT1G) still no power light or frag, whats the next component to test/replace. Thank you. TEd Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 9, 2019 Author Report Share Posted August 9, 2019 (edited) 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. 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 August 9, 2019 by bigted1977 Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted August 10, 2019 Report Share Posted August 10, 2019 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. 1 Quote Link to comment Share on other sites More sharing options...
KaosEngineer Posted August 10, 2019 Report Share Posted August 10, 2019 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. 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? 1 Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 10, 2019 Author Report Share Posted August 10, 2019 collector is 3.45 emitter 5.35 base 4.6 power on is the white one, 0v when standy by, 3.4v when pressed but does fluctuate when held some times as low as 2.6 when fluctuating. Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 14, 2019 Author Report Share Posted August 14, 2019 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 Quote Link to comment Share on other sites More sharing options...
SS_Dave Posted August 15, 2019 Report Share Posted August 15, 2019 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. 1 Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 15, 2019 Author Report Share Posted August 15, 2019 Yes getting 2.3 volts on the clock cap with the mother board disconnected so that's good too. I'll likey build a mod chip or buy one and give that a try. Thanks all. Ted Quote Link to comment Share on other sites More sharing options...
SS_Dave Posted August 15, 2019 Report Share Posted August 15, 2019 I would say the cap is fine then. A modchip from Fleabay or aliexpress is aound $4.5 usd then once up and running if you don't like the supplied BIOS you can flash it with your preferred one. Good Luck SS Dave Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted August 20, 2019 Author Report Share Posted August 20, 2019 Aladdin chip arrived soldered inn and lpc rebuilt. No change still dead. Ted Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted March 15, 2021 Author Report Share Posted March 15, 2021 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 Quote Link to comment Share on other sites More sharing options...
sweetdarkdestiny Posted March 16, 2021 Report Share Posted March 16, 2021 5 hours ago, bigted1977 said: Not got a dvd drive handy so with chip removed give error 12. Because you don't have a DVD it gives you that error. You need a EvoX noDVD bios (or iND/x2) to get rid of this error. If you will launch the original bios you need a DVD drive. Quote Link to comment Share on other sites More sharing options...
bigted1977 Posted March 16, 2021 Author Report Share Posted March 16, 2021 (edited) 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 March 16, 2021 by bigted1977 Quote Link to comment Share on other sites More sharing options...
camilofer Posted June 8, 2021 Report Share Posted June 8, 2021 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 Quote Link to comment Share on other sites More sharing options...
Gorreala Posted June 29, 2023 Report Share Posted June 29, 2023 Im having the same issue. i checked all points of the Q7C2 got 5 and 4.6 and 3.28 on the single side. im guessing my collectors is done if not getting 3.30 or higher. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.