Mastero MK-4.5 250w 12v DC-DC ATX PSU + SDC - Page 8

MatrixPC · 02-15-2005, 10:28 AM

When you first hook up power to the main connector, does the jumper wire next to the 204 POT, jumper header and small 12V relay has ground? To test that, put the red lead of the multimeter to power (battery) and the black lead to that jumper wire. This jumper wire has ground when the SDC is working. If that wire doesn't have ground, the SDC part has problem. This ground is to power the small 12V relay right next to it.
Now put a jumper on that jumper header next to 204 POT, the PSU should be in it standby state. The STBY LED should lit up. PSON, STBY connector should read 5V, if not, the Stand By 5V regulator is dead or the relay next to it is dead.
If all fine, move to the main relay, to turn it on, Ground PSON pin by shorting pin 14 and 13. If that main relay doesn't click, well replace it.

me and me lude · 02-15-2005, 12:59 PM

no that first part is NOT grounded, although with the power disconnected there is a 500odd kOhm connection from that part to ground :S

btw, what does jumper J1 do?

MatrixPC · 02-15-2005, 04:21 PM

When the SDC is working (ON state), that part, the jumper wire next to J1, will have GROUND. When the SDC is OFF, that jumper wire doesn't have anything. JP1 bypass the SDC's system off part and put the PSU in its standby state. In standby, the small 12V relay is always on (coil always energized) and thus the STBY pin always get 5V. And so USB devices will always on. Just like home AC PSU when you shutdown the PC. If you short J1 and STBY doesn't have 5V, either the 12V relay is dead or the 5V regulator (LM1084IT-5) is dead.
To find out which one is dead, test pin1 (Left most on component placement view) of the 5V regulator against ground to see if it show battery voltage (12V). If there is 12V, then the relay is okay. If not, the relay is dead. If there is voltage on that pin and no 5V output, then the 5V LM regulator is dead.

me and me lude · 02-15-2005, 09:55 PM

ah, turns out it was a blown 4148 diode that was shorting 12V in and ground when J1 is jumpered

but... there must be a problem now with the shutdown controller part..

MatrixPC · 02-16-2005, 10:16 AM

If the 1N4148 diode accross the small 12V relay's coil is burned, replace it it 1N4007. On mine, that diode is burn too when the SDC is working. I replace it with 1N4007 and has NO problem at all.

Just to make sure all the voltage read properly before hooking up the mobo. Short Pin14 and Pin13 to turn the PSU on and test the voltage.
Also I test it first with my old "throw away" mobo w/P3 350 to see if all work before hookup to my carPC.
Since you already have a shorted on the 787, you may double check that as well.

me and me lude · 02-16-2005, 11:21 AM

but if i leave the j1 jumper off, it won't work, so there is anothe prob with the sdc.... any ideas?

MatrixPC · 02-16-2005, 12:25 PM

With the SDC On, check to see if there is 5V or something reading from the Left most Pin where it connect to 10Kohm resistor of the BD677 transistor. If it show voltage, but no tround coming out of the middle pin (that pin connect to the jumper wire), the BD677 is probably dead (caused by 1N4148 burned earlier). Mine blow a hole when the diode die.
Basically the voltage from 74HC14 pin6 going thru 10K resistor to switch the BD677 transistor which connect the Middle and Right most pin of the transistor which supply GROUND to the relay.

me and me lude · 02-16-2005, 10:47 PM

ah thanks, swapped out the bd677 and sdc works again.....

now my atx header seems to be shorted when the power supply is on
would it be a problem with the 5v relay

MatrixPC · 02-17-2005, 09:44 AM

What did you mean "Shorted"?
I should of tell you about the ATX header, but forgot. Here you go.
The ATX headers ATX1, and ATX2. One of them connect to the power switch the same way you connect to the case's power switch in desktop.
The other header connect to the mobo PW header. This is the trick. When you connect the header to the mobo pw header and the PC is running, short the "KILL" switch. The PC should shutdown/hibernate depend on how you setup in Window's power option. The action is the same as you press the power button on your home PC. If it doesn't do that, switch the pin/connector around (1 become 2 and 2 become 1) . It is because the small 2N3904 transistor need one side to be +. I forgot which is which. On the mobo power switch header, one of them show 5V, the other has nothing.

me and me lude · 02-17-2005, 10:03 AM

right now when i attach the atx header to the motherboard, it shuts it down as soon as i turn on the power
so it feels like the power "button" is constantly depressed

MatrixPC · 02-17-2005, 01:48 PM

Check to see if there is connectivity between the pins on those ATX header.
If there is, well you have to replace that 2N3904 transistor.
Try to boot the PC without attaching the power button to the ATX header. Instead, hook up directly to the mobo to see if the PSU works.

scaccess · 02-17-2005, 07:05 PM

How can I buy a psu kit from you there is no link to the shop on your site?????

Mastero · 02-18-2005, 05:59 AM

hello i am back ... wats going on was on a trip to US then to goa

any help required?

Mastero

never_stock · 02-18-2005, 06:37 AM

Quote: Originally Posted by Mastero

Specification:~

Input

8vdc ~ 30vdc (Can survive a Diesel motor start)

Output

+5vdc @ 12A (max)

+3.3vdc @ 12A (max)

+12vdc @ 10A (max)

+5vstby @ 5A (max)

-5v @ 500MA (max)

-12v @ 500MA (max)

so in reality its only good for about 180watts.... as a high current standby line is useless, and maximum currents mean very little. expecially when they are just made up.

Mastero · 02-18-2005, 06:49 AM

wats your point never ?

MAstero