Own Custom Build Computer With ECS Motherboard-No POST

[momaka]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Here, I would really like to know if you have any idea of what kind of tip should be used to rework this type of array chip.

You can do this two ways without hot air:

1) By using two soldering irons...
Bridge all of the pins on the array component and heat the bridged pins on each side with each iron. Then slide the component off. Relatively easy method. That said, if your irons have pencil-shaped tips, you still might struggle a little because those tips have poor heat transfer. Get chisel- or bevel-shaped tips *OR* if the tips of your irons are made from copper, then sand the tips down to proper chisel shape.

2) Use a large spoon-shaped tip (large enough to cover the entire array component)...
Like method 1 above, bridge all of the pins of the array component first. Next, fill the spoon-shaped tip with solder. Finally, put some flux on the bridged pins of the array component and put the spoon-shaped tip on top of the array component. Let the solder melt and carefully slide the array component away from it's position or use tweezers to lift it while still heating with the iron.

I use both methods 1 and 2 above, depending on how big the component is. I have a 3.5 mm spoon-shaped (carved in) tip on my regular 30 Watt soldering iron. Actually, that tip used to have a conical shape, like yours. But over the years, it became worn and "pitted" on one side. I then sanded it down into a chisel tip. When it became worn again, it got that spoon-like shape, which now I find is excellent for doing SMD work. I can remove SOT-23 components in seconds. Not hot air needed at all.

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

A small chisel tip may help, but don't get some needle-point tip, they don't carry heat very well and actually work worse.

I find doing 0603 size or so components that a 1.2mm chisel is good, but even that doesn't work on one of those arrays very well.

Last time I soldered one of those arrays I used solder paste and hot air rework. You may be able to get away with a soldering iron if you use a 1.2mm chisel tip and LOTS of flux. Flux is one of the key things here.

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Hi Agent24,

I had previously managed to desolder one of this array capacitor (flat pins) that ties to the ic ST75185CTR for pulling the logic level low as motherboard drive PS_ON# normally with this open collector driver that can pull the signal level down. However, unfortunately while trying hard to remove it from the motherboard, a few pins of the array capacitor have been destroyed by overheating them. Here, I would really like to know if you have any idea of what kind of tip should be used to rework this type of array chip. I've had a magnifier with me while I tried to resolder the chip but not that efficient cause the soldering tip of my iron is large conical tip...so do you have any recommendations on what type of tip should be small enough to be prepared and perform this job as I couldn't find any useful method anywhere else for this one..

THANK YOU.

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

....so lately I resoldered the ST75158CTR, an SOP-20 ic but unfortunately I lifted 2 tiny pads on the motherboard while using my soldering iron with temperature control. The reason is that it doesn't have any auto-reset on the temperature setting and i kept increasing the temperature till it was around 400°C. This is a big mistake and I had previously messed with its' setting so the temperature is all the way out of range..(refer PIC-A)

...you can actually notice that I rewired the lifted pads by using 2 pieces of tiny wires all the way to the ST75185CTR which has the lifted pads on the other side of the motherboard. I had used a bit of epoxy glue too, in order to tack those tiny wires down firmly on the motherboard before soldering them to the ic pins...(refer PIC-B)

...The IC itself might have failed but also there could be an issue with its supply rails going out of spec or some part on an output pin is shorted to ground, like one of the capacitors on a data line maybe.

...I think I eventually found the culprit to the no POST problem and it's the capacitor EC29 which actually is the output feeder to the CPU logic (V_FSB_VTT ). Its' (-) pin is shorted to the GND. It's as well coupling the DATA line signal to the ic ST75185CTR. The capacitor which as well couple to this ic failed to work in this case and causing over voltage to the ic where it's responsible to pull logic low to 5VSB then 12V can be drawn from the PSU. (refer PIC-C). Capacitor EC29 can be found on PG.04 of the SCHEMATIC or here (https://www.badcaps.net/forum/showpo...count=11). For your information I've ordered stock no.520-1438 from (http://my.rs-online.com/web/p/alumin...32303134333826) to replace the EC29 on the motherboard

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Most parts can follow a pretty standard reflow profile. If there is nothing specified in the datasheet just go with the usual temperature, taking care not to exceed any maximum temperatures listed.

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

...686-4954 should work as replacement.

Hi Agent24,

Do you have any idea about the correct soldering temperature for ST75185CTR or 686-4954. It should be an SOP-20 ic if not mistaken. The datasheet does not provide any reliable information on the reflow temperature for the ic. Can you please help me on this one? I'll still try to work on it this weekend...

Thank you

[ChaosLegionnaire]

Re: Own Custom Build Computer With ECS Motherboard-No POST

ecs seems to like using ost caps on their boards. my experience with these caps on p4 boards has been horrible/terrible to say the least. they often cause all sorts of strange issues on boards.

i once briefly had an ecs p45 board. it was a boardful of osts except for the cpu vrm out area which used polys. i got that board as part of a bundle of a sale of second hand parts. wanted the cpu, cpu cooler and ram but not the board, so i resold the board quickly. didnt trust those osts. would be a pain to recap all the 20+ caps on it too.

reviews of ecs boards have also shown they perform poorly in overclocking. this means that as the components age, there is very little headroom for allowance when things go wrong with the board components.

so if u want cheap, u got cheap. u get what u pay for.

[fzabkar]

Re: Own Custom Build Computer With ECS Motherboard-No POST

I'm still using a 15-year-old PCChips motherboard on a daily basis. My previous PCChips motherboard lasted for 16 years or so. They both run/ran 24/7.

As for the RS232 IC, sometimes these fail when using long cable runs.

[Merlin_AmiBay]

Re: Own Custom Build Computer With ECS Motherboard-No POST

I don't wish to devalue your efforts with this board, however, ECS (Elitegroup) bopards have always been cheap, nasty and troublesome. A long time ago, a friend of mine bought an ECS motherboard to upgrade (sic) his PC and the first message 5that we got on booting up with a Windows 95 CD in it was that the board needed a BIOS update before it would even install Win 95. We got the BIOS update and eventually got Win 95 installed, but the board crashed randomly and it was never fully stable whatever we did with it.

ECS Elitegroup motherboards are on my Top 10 list of crappy boards, right up there with the Abit ST-6 RAID board.

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Also you may want to look into reasons why the chip is overheating. The IC itself might have failed but also there could be an issue with its supply rails going out of spec or some part on an output pin is shorted to ground etc, like one of the capacitors on a data line maybe.

686-4954 should work as replacement.

[fzabkar]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Your photo shows a UTC75232L:

https://cdn.badcaps-static.com/pdfs/...776b6b3f8f.pdf

The 75232 is a very common part that was manufactured by several companies:

http://search.datasheetcatalog.net/key/75232

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Are you still getting 0v on EC49's positive lead?

Hi Agent24,

It has been a while since the last post on testing the discrete signal through the capacitor EC49's positive lead. The EC49 capacitor is working perfectly but I found a badly overheated SMT package I.C. which happens to be the ST75185CT-S. From the schematic (page 25), it controls the COM port by getting a dual switching power deriving from the 5V and +12V PSU (flyback converters). It's a serial port controller, the one with label U1 from the picture I've attached...

Questions
I removed the ST75185CT-S SMT controller from the motherboard. I would like to ask if the picture here is the one which I can order for replacing the shorted one. I will be ordering component no./stock no. 686-4954 from http://my.rs-online.com/web/p/line-t...ivers/6864954/. Please do let me know if this is the real problem where the I.C. should be replaced with a new one?

Thank You...

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

If the output from the middle point of ER10 and ER11 is 1.067v then that is OK. Maybe the schematic is just wrong as to which pin of the opamp are connected to that point. Try a continuity check between the VREF1_05V node at ER10 and ER11 and opamp pin 2 or 3. Maybe it's actually the other way around to what it shows in the schematic.

Are you still getting 0v on EC49's positive lead?

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

..........circuit with D9 (the 431 zener) on Page 11 generates the VREF1_05V and if those resistor values for ER10 and ER11 are correct then VREF1_05V should indeed be 1.05v. Can you check the cathode of D9....?

D9431-S SHUNT REGULATOR (HA17L431ALTP)

PIN_C (CATHODE): 2.47V

As for the resistors ER10 and ER11, I found out that both of the resistors are having the same 2.47V which is slightly lower here whenever I measured them towards the gnd or towards the Ref pin of the D9431-S SHUNT REGULATOR. BTW, I too tried to measure up ER10 towards the other end which also happened to be VREF1_05V output and both of the ER10 and ER11 showed 1.067V. Here it's slightly the same voltage that I got frm PIN_02 of the U4A opamp.

Does this shows that the mobo is unable to detect the presence of the VREF1_05V and it doesn't fully boot up? Would this be a faulty 5VSB rail that puts up a high surge on the EC controller circuit that drive the MOSFET and voltage controllers? I suspect that the voltages should be in HIGH state will likely be the +2.5V, +1.8V and +1.5V which also caused the +1.05V to be in LOW state or not present due to certain ic that control the signal breakdown at this point.

Also, is the VCC3 input to ER9 correct?

..it seems that the VCC3 input which should be 3V towards ER9 is now 2.86V. This voltage will likely unable to fully supply the other controllers. Can it be the VCC3 output voltage which tied to the 3VSB and 5VSB of the U12 controller is probably too low?

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Hmm.. Well there are 3 things here that I find strange.

First is that Pin 3 of U4A is supposed to be 1.05v as per the schematic, yet you measured it as 2.25v.
The circuit with D9 (the 431 zener) on Page 11 generates the VREF1_05V and if those resistor values for ER10 and ER11 are correct then VREF1_05V should indeed be 1.05v. Can you check the cathode of D9 and see if it is 2.5v as it should be? Also, is the VCC3 input to ER9 correct?

Secondly, you say you measured 1.53v at Q21's source pin, but previously you said you measured 0v at EC49, which is connected to it. Can you check EC49 again, be sure you are measuring the correct lead?

Edit: Also if Q21 drain is 2.94v, that suggests the 1_8VSTR rail is too high. If you measured that correctly then perhaps U14 or some of its components are bad.

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

.....But note also that the VDDQ rail Is derived from the 1_8VSTR rail. See the schematic in page 11. They drop the 1.8v 1_8VSTR rail to 1.5v to make VDDQ, using Q21 and the opamp U4A in a linear regulator circuit.

The opamp U4A is enabled by the reference signal VREF1_05V

So, for VDDQ to come up to 1.5v, you need 1_8VSTR to be present at Q21's Drain and also the VREF1_05V rail to be present at the U4A opamp.

Check those......

DAC-AS358 SOIC-8 (Pg.11 schematic)

PIN_03 (inverting input): 2.25V
PIN_02 (non-inverting) : 1.06V

......as U4A is part of the digital-analog converter, thus the ref signal 1_05V is pegged as HIGH by the +12V rail of the PSU. If the ref signal is available the 1_8VSTR will be present too and this voltage can be obtained frm the Q21's transistor Drain pin.

FET-APM2055N (Pg.11 schematic)

Q21's drain pin (output) : 2.94V
Q21's source pin (VDDQ): 1.53V

....about a thing that confused me was that the VDDQ that provides power to the ICH returned as normal which as you can checked frm the specs, 1.5V. I did noticed that the 1.5V can be unavailable without any reasons for a couple of times when I checked the EC49 for voltage. All voltages tested here are without the presence of the CPU. Could this be a CPU doesn't get turned off, but from time to time the clock signal stops. Do you have any ideas what is causing this...and as for the voltages that you mentioned frm the previous post which should be Q22 and Q23 I just don't have enough time to check them out yet, so the readings shall be available on the next post. Sorry for that now...

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

...wow do you mean that I'm getting into all this suspected TCC sensor broken will likely be wrong...? Do you have any ideas to actually locate the right Southbridge_VCC or other voltages on the motherboard? For the voltage of the Southbridge_VCC, I abruptly measure the positive legs of all those 3 Nichicon capacitor located between the Southbridge and the ram slots, so am I measuring the VCC voltage correctly?

I don't know for certain that the TCC circuit is OK, but the PS_ON# signal should be 0v in normal operation so that is not cause for worry.

Yes, measuring on the positive leg of the capacitor is good. I was just worried for a second when in your photo the arrow was pointing directly from the capacitor body itself. I just wanted to make sure you were checking in the right place.


OK. To the voltage reading...

The voltage at EC49 is called 'VDDQ' in the schematic (page 11). It's one of the power lines that supplies power to the ICH.
According to the power distribution chart it should be 1.5v. If it's 0v that's not good as you already know.

But note also that the VDDQ rail Is derived from the 1_8VSTR rail. See the schematic in page 11. They drop the 1.8v 1_8VSTR rail to 1.5v to make VDDQ, using Q21 and the opamp U4A in a linear regulator circuit.

The opamp U4A is enabled by the reference signal VREF1_05V

So, for VDDQ to come up to 1.5v, you need 1_8VSTR to be present at Q21's Drain and also the VREF1_05V rail to be present at the U4A opamp.

Check those and then let's see if they are OK too.



Also, there is something else I noticed, when re-reading your first post. You said the front panel Power LED does not turn on. I find this rather interesting.

The front panel\case Power LED is driven through lines GLED0 and GLED1 (there are two for when you use a dual-colour LED) which are in turn switched via Q22 and Q23, a couple of SMD 2N3904 transistors. These transistors get their control signals from the SIO chip.

So, if the front panel LED is not coming up, it makes me think the SIO chip may not be sending the LED0 and LED1 signals to those transistors.

Q22 and Q23 are near the front panel connector on the board. See the image I have attached.

Can you measure the voltage on all pins of both those transistors and report back with what you find?

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Also, I am just wondering where you measured the Southbridge VCC voltage. Your photo shows an arrow pointing to a capacitor. Did you measure the voltage on the positive lead of the capacitor, or on the capacitor body itself?

...wow do you mean that I'm getting into all this suspected TCC sensor broken will likely be wrong...? Do you have any ideas to actually locate the right Southbridge_VCC or other voltages on the motherboard? For the voltage of the Southbridge_VCC, I abruptly measure the positive legs of all those 3 Nichicon capacitor located between the Southbridge and the ram slots, then I just get one of the capacitors reading which is EC49, so am I measuring the correct VCC voltage here?

[Agent24]

Re: Own Custom Build Computer With ECS Motherboard-No POST

Sorry I think I missed the previous email from this thread, I didn't see you were still going with it. I'll try to look at the schematic tomorrow and give you some ideas to look at (bear in mind, I am not an expert either, though)

I can say though that I don't think there may be anything wrong with your TCC circuit etc...

The PS_ON# signal that goes to the PSU green wire is what is called an 'active low' signal. That means it is active (working) when it is at a logic low state (eg: zero volts). You can tell this is the case as there is a # at the end of the signal name.

Other methods of showing an active low signal line are ! or / often, eg: !PS_ON or /PS_ON.

Basically, the PS_ON# signal should be 0v in normal operation.


Also, I am just wondering where you measured the Southbridge VCC voltage. Your photo shows an arrow pointing to a capacitor. Did you measure the voltage on the positive lead of the capacitor, or on the capacitor body itself?

[LENOVO-A880]

Re: Own Custom Build Computer With ECS Motherboard-No POST

..lately I started going through all the rails and references voltages to see if there are any problems or shorts. This is what I have found for so far:

STANDARD SYSTEM VOLTAGES ON ECS G31T-M7

CPU_VTT VOLTAGES: 1.189V
RAM_VDD VOLTAGES: 1.89V
RAM_STB VOLATGES: 0.946V
NORTHBRIDGE_VCC VOLTAGES: 1.238V
SOUTHBRIDGE_VCC VOLTAGES: 0V (refer PIC)

It's clearly that here one of the VCC has been shut off to prevent any further catastrophic failure to other parts of the system. I decided to moved on to test the THERMTRIP voltage of the Southbridge to be sure that it's the cause of the shut down and without any doubts it reads a 1.189V. I think the TCC or the THERMAL CONTROL CIRCUIT is asserted so that the silicon of the CPU when core reaches 135°C can be well protected from extreme thermal damage. BTW for other issues like heatsink falling off where there is no BIOS code involved - the THERMTRIP signal is tied into the front power switch logic, and causes PS_ON# signal to be de-asserted. That remove the power of the VCC and VTT completely to avoid thermal runaway of the processor.

*UPDATE*:The advantage of the TCC scheme might even require the user to turn off power at the back of the computer, then turn it back on, before the system will allow the front power button the be used. If you then press the front power switch again, it would shut down just as quickly for second time.

....In my case here I'm likely having a short or a cracked resistor within the TCC scheme when I checked on the ceramic SMD chip(refer PIC) near to the SIO chip since the PS_ON# signal is also not present at all - my digital multimeter shows 0V when I probe it on the green wire of the new FSP PSU. I would like to know if this chip can be replaced or can it be purchased anywhere else? And can it be possible to de-soldered it from the motherboard and how? Does anyone here have any ideas ?