Samsung DCB-P853Z (DVB tuner/recorder)

[OniJon]

Hello all the experts here in the badcaps!
I've got myself a broken DVB recorder by samsung. The unit wasn't powering on and all that, so I changed all of the caps in the psu, besides the 450V one. This fixed the powering on issue.

Next thing after this is that the device could boot up just fine and work too. Or it would be stuck on boot with all the red lights just on. In this state, it doesn't do anything by pressing on the power or any other button. Hard resetting it from the back switch may or may not get it working again for a period of time. After a working period, it could just hang or boot again. When it works and you switch it off from the front panel, the fan may stay on even though the other components power off.

There are few regulators on the motherboard, here's what I've measured.:

U303
AMC 1117 (sot-223) = it doesn't have prefix (1.8-5.0) so accounting to the datasheet, it's variable output regulator.
big tap = 1.241V
GND = 0.001V
OUT = 1.241V
IN = .OL

U1021
KIA 78D25F (TO-252) = 2.5V fixed.
big tap = 0.001V
pin 1 = .OL
cut pin = 0.001V
pin 3 = .OL

U1027 & [U1025]
KIA 78D05F (TO-252) = 5.0V fixed. There are two, one between the tuners and a pain in the ass to measure.
big tap = 0.001V
pin 1 = .OL
cut pin = 0.001V
pin 3 = .OL

U102 & [U101]
M39100 (sot-223) = 3.3V fixed. There are two, one between the tuners and a pain in the ass to measure.
big tap = 0.001V
in = .OL
center = 0.001V
out = .OL

Q1206
Not sure what else it could be, could be the reset thing RA26P (sot-23).
Gives .OL and 0.001V too.

What else I should measure here, help is greatly appreciated!!

[OniJon]

Re: Samsung DCB-P853Z (DVB tuner/recorder)

Ok, the fan staying on is actually a firmware thing which came with a update, it helps to keep the thing cool because it takes like 18W from the wall in standy.

[retiredcaps]

Re: Samsung DCB-P853Z (DVB tuner/recorder)

What else I should measure here, help is greatly appreciated!!

Your OL readings suggest you have an autoranging multimeter, but your reported readings suggest you have a manual ranging multimeter set to 2V DC scale.

Retake the readings with your manual range multimeter set to 20V DC.

PS. Post a picture of your multimeter for a retiredcaps' bonus point.

[ComputerGeek]

Re: Samsung DCB-P853Z (DVB tuner/recorder)

OK this is just an idea but have you checked the Hard drive in anyway? If it is going bad I could see it causing this problem. Just an idea it might not be a Component.

[OniJon]

Re: Samsung DCB-P853Z (DVB tuner/recorder)

OK this is just an idea but have you checked the Hard drive in anyway? If it is going bad I could see it causing this problem. Just an idea it might not be a Component.

Yes, actually I took it out and it had few bad sectors which are fixed now in my computer by seatools.


Ok. I changed the multimeter to my work one. The market one showed whatever it wanted at given time and it's hard to set to measure anything.

U303
AMC 1117 (sot-223)
big tap = 1.23V
GND = 0.00V
OUT = 1.23V
IN = 3.23V

U1021
KIA 78D25F (TO-252)
big tap = 0.00V
pin 1 = 2.51V
cut pin = 0.00V
pin 3 = 3.22V

U1027 & [U1025]
KIA 78D05F (TO-252)
big tap = 0.00V
pin 1 = 5.39V
cut pin = 0.00V
pin 3 = 5.04V

U102 & [U101]
M39100 (sot-223)
big tap = 0.00V
in = 4.92V
center = 0.00V
out = 3.27V

Q1206
RA26P (sot-23)
pin 1 = 3.23V
pin 2 = 3.23V
pin 3 = 0.00V

These measurements look just fine to me?

[retiredcaps]

Re: Samsung DCB-P853Z (DVB tuner/recorder)

Yes, actually I took it out and it had few bad sectors which are fixed now in my computer by seatools.

As ComputerGeek suggested, your problem may have been the hard drive. You may want to reformat and reinitialize the complete system if the OS allows it.

Ok. I changed the multimeter to my work one.

These measurements look just fine to me?

I agree.