Your Digital Media Has Never Looked So Good

Topic Author
Posts: 124
Joined: Thu Aug 19, 2004 4:38 am
Location: Columbia, MD

List of parts to fix your power supply

Tue Dec 05, 2006 8:47 pm

I have compiled the following parts list for those who dare to repair their own dead power supply. I just finished fixing 2 of mine with the listed parts from Digikey. If you purchase more than $25 then you don't have to pay the extra $5 fee.

The parts listed from the second supplier (Mouser) should be compatible with the parts from Digikey. I just posted them so that you would have a choice.

-BJ Johns

Label  Mfg Part #  Description                Digikey #      Page #  Price/$
-----  ----------  -------------------------  -------------  ------  -------
U1     UC3842B     PWM Controller 8-DIP       497-4602-5-ND  734      1.16
Q3     2SK2996     N-Channel MOSFET 600v/10A  2SK3569Q-ND    939      1.88
C5     47uf/35v    Radial Capacitor 6.3x11.2  P11232-ND      1176      .17
C15    470uf/35v   Radial Capacitor 10x20     P10301-ND      1176      .72
C18    2200uf/10v  Radial Capacitor 10x20     P5522-ND       1173      .79
C19    2200uf/10v  Radial Capacitor 10x20     P5522-ND       1173      .79
C20    2200uf/10v  Radial Capacitor 10x20     P5522-ND       1173      .79
                                                                      6.30 + 5.00 + tax + shipping

Label  Mfg Part #  Description                 Mouser #         Page #  Price/$
-----  ----------  --------------------------  ---------------  ------  -------
U1     UC3842B     PWM Controller 8-DIP        511-E-UC3842BN   332       .90
Q3     2SK2996     N-Channel MOSFET 600v/9.5A  512-FQPF10N60C   426      2.63
C5     47uf/35v    Radial Capacitor 5x11       647-UVZ1V470MDD  593       .22
C15    470uf/35v   Radial Capacitor 10x16      647-UVZ1V471MPD  593       .64
C18    2200uf/10v  Radial Capacitor 10x20      647-UVZ1A222MPH  593       .86
C19    2200uf/10v  Radial Capacitor 10x20      647-UVZ1A222MPH  593       .86
C20    2200uf/10v  Radial Capacitor 10x20      647-UVZ1A222MPH  593       .86
                                                                         6.97 + shipping

Posts: 119
Joined: Tue Nov 30, 2004 1:36 pm

Sun Dec 10, 2006 4:33 pm

Hey BJ,

Thanks for the parts list. Do you have a how-to also so we know where the parts go and what specifically to do?
Topic Author
Posts: 124
Joined: Thu Aug 19, 2004 4:38 am
Location: Columbia, MD

Mon Dec 11, 2006 6:21 am

Sorry, no how to as I would assume that anyone that wants to repair their own power supply should have some basic electronics experience. If not, then this is not something that you should attempt to do yourself.
Posts: 1
Joined: Sun Feb 18, 2007 8:11 pm

Sun Feb 18, 2007 8:20 pm

Nicely done. Thanks!
$7 for parts. Ordered a double quantity. Figure I'll be doing this again in 18 months. Got a working supply for $7 and some extra solder and solder wick to boot for $25 and no shipping costs! Next time I might look for higher WVDC caps and a 7805 though. Mine looked pretty cooked but it still worked.
Posts: 180
Joined: Sat May 28, 2005 11:35 am
Location: Colorado Springs, CO

Mon Feb 26, 2007 9:44 am

One of you guys should start a little "Roku Fix and Upgrade" side business! Once mine goes out (can't believe it hasn't alread) I'll definitely be looking to get it fixed...
Posts: 24
Joined: Mon Jan 03, 2005 7:42 pm
Location: Rhode Island

Sat Mar 03, 2007 10:30 pm


Thanks for posting this list, I just repaired the supply in one of my HD1000s. The PS had not completely failed, video had degraded and if the wireless adapter was plugged into the USB port the video would go bland. The MOSFET and PWM controller were still good so I replaced the caps only. C15 was split on top, and C18-20 were bulged on top. C5 looked good, but since I had the heatsink off I replaced it anyway. I bought some extra parts from Digikey in case I need to fix my other HD1000 in the future.

To try to help the heat problem I enlarged the holes in the chassis near the power supply and every other hole on the side of the top cover. I will wait a day or so and see if it seems to feel cooler than before.

Posts: 17
Joined: Thu Nov 11, 2004 5:05 pm

Wed Mar 14, 2007 3:59 am

Make sure they are low ESR (Otherwise known as low impedance), 105 degree C capacitors. Also make sure that they are a decent brand, from the following list:
Most other Japanese manufacturers.

Avoid Chinese ones like the plague

This is a known problem with electrolytic capacitors from a certain time-frame. If you replace them now, before the PSU dies, you won't have to replace the MOSFET and PWM controller (As well as the caps) at a later stage.
Receiver - Onkyo TX-NR901
Front - Mordaunt Short 908
Centre - Mordaunt Short 905C
Rear - Mordaunt Short 902 Signature
Surround - Mordaunt Short 903
Sub - Mordaunt Short 912
Media Player - Roku HD1000
Plasma - LG RT50PX10
DVD - Samsung DVD-HD747
Posts: 7
Joined: Sun Nov 04, 2007 8:15 pm


Sun Nov 04, 2007 8:57 pm

Thanks so much for the list.

I bought an HD1000 off of Craig's List with a bad power supply. That same night, I ordered 2 sets of parts from digikey. The parts arrived before the Roku did. I replaced the 2 ICs and nothing. I replaced the 5 caps and voila!

Guys, give this a try. Worse thing that can happen is to buy the external power supply.

Here is a little more step-by-step. I wish I had thought to take pictures.
Make sure you use solder-wick or a solder-sucker and not just push on things.

Tools needed: A soldering iron with a small tip, desoldering tool (wick or suction), solder, small tool for lifting IC off (screwdriver or pliers), wire cutters/pliers

1) open the chassis after removing the main power.
2) unplug the power supply from the main board.
3) examine the metal heat sink surrounding the parts. Remove the two screws on the sides that hold the transistors to the heat sink. There are 4 spots that it is soldered onto the circuit board. Remove the solder and then remove the shield.
4) examine the board and look for the part numbers. On the ICs, make sure to remember where the little divot on the end of the top is. This identifies the direction you have to reinstall the chip. On the capacitors, look at the side of the cap, there is a '-' on it. The board has a '+' labeled under the caps but it is a good idea to note where the '-' is anyway.

Note: my transistor was under a little plastic boot. Just take it off and reuse it.

5) remove the parts and replace with the new ones.
6) trim the leads on the capacitors after installation
7) secure the board (without the heat sink) back to the roku and reinstall the ground wire.
8) Test the power supply. The light on the power supply should light. If not, recheck the work.
9) remove power and the power supply
10) install the heat sink and solder it back on.
11) The transistors have a white heat transfer paste applied. You really should apply more when you reinstall the heat sink. I used paste from installing CPUs. I hope that is fine. Reinstall the retention brackets and the two screws to hold the transistors to the heat sink.
12) reinstall the power supply and the ground wire. (but no power to wall)
13) plug power cable to mother board
14) plug repaired roku into the wall.
15) Hopefully enjoy years more of Roku goodness

I hope this helps some people. If you smoke your roku, I accept no liability.

Good luck and take your time.

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