Surface resistor Hey I have a asus 1001ha, but the motherboard says 1005ha, around the input power plug, there are three small surface resistors the smallest on the bottom has blown, and I wanted to know where I can find the voltage for that resistor so I an replace it without damaging the rest of the board.

Does your unit power on at all or is it just not charging the battery?

If it's just not charging your battery the likely cause is the battery has just gotten used up, replacements are usually between $50 and $89 CAD

Upgrading BIOS is dangerous and can cause fatal damage to your PC. If you are aware of that and decide to take this risk, then continute. 1. Visit http://support.asus.com/download/download.aspx?SLanguage=en-us, search 1001HA and choose DOS as operating system. Download latest bios rom file.
2. Save and extract the downloaded file. You will get a rom file named like "1301.rom" 3. Format a usb pen drive to FAT-16 partition. In my case I used a 32 MB SD card which came with my old Kodak camera, and I used a SD card reader that PC can see it as a usb disk. Copy 1301.rom to its root folder and rename it to 1005HA.ROM. The reason for renaming it to 1005HA.ROM is that EZ Flash on this 1001HA netbook looks up rom with this name. If EZ flash failed saying trying to find a rom file with another name, just shutdown the netbook and rename your rom file to the required name and try again. 4. Plug in the usb pen drive and reboot the netbook. Make sure that during the ASUS splash screen, press ALT+F2. Then EZ Flash will run automatically and try to locate the usb drive and read from file 1005HA.ROM (in my case). 5. It takes around one minute for me to upgrade everything. DO NOT TURN OFF OR EVEN TOUCH YOUR NETBOOK DURING UPGRADE. Read the messages on the screen and when it says you can press the shutdown button, you can turn off your system. 6. Turn on your netbook again and enter BIOS to check if the BIOS version is up to date.
http://www.youtube.com/watch?v=61awfpVe49k&feature=player_detailpage

I think first You need to check the cable from socket to mainboard (inside netbook).

The resistors are color coded.There should be 3 bands which are slightly separate from the 4th band.The 4th band is usually gold,silver,or i forget the third color which is actaually a %.The top 3 bands can tell me the value of the resistor.If you tell me all 4 colors I should be able to tell you the value,with the gold/silver/whatever as the fourth.The first one should be right near the end or top.The only 1 problem will be trying to determine the wattage rating but is usually very small within a circuit.Greg

I believe it is r16 which is a 10 ohm surface mount resistor. It is the closest thing in parallel to r55 (.47 ohm @ 2w)

DO NOT REPLACE THE FUSE !!! You will do more damage.

I just repaired one of these. A small ceramic surface mounted cap very near where the +/- 85 volt connectors plug onto the board blew up.

This left a sputtered mess on the insulating material at the right rear corner of the power supply.

The net parts list of parts I had to replace:

1. Main IGBT transistors on heat sinks. You have to remove the heat sinks to get at the mounting screws. 1MBK50D or equivalent. I used DigKey part APT28GA60BD15

2. One 1N4148 surface mount diode that is for gate drive speedup. D24 and D25. (don't remember which one was shorted)

3. All four driver transistors for the gate of the IGBT's. @ each 2SA1020 (PNP) and 2SC2655 (NPN). These are tall TO92-like transistors and I believe that at least one of these I had to get from Mouser.

4. Transistor T9, suface mount BC856B (PNP)

5. Replaced all four surface mount caps, one had exploded.
C50, C51,C54,C56. Replace with 0.01mfd/200 Volt 1206 style surface mount caps Digikey 478-1511-6

6.Replaced ceramic wire wound 10 Watt stand up resistors that were blown open. Replaced with 20 ohm design change. These slowly charge the main input filter caps and when supply is stable, a relay shorts them out. If you have replaced the fuse, you LIKELY blew them out. Original value was 10 ohms on some units. This was a Mouser part. 280-PRM10-20-RC

7. The 2153 switching reg chip IC1. This chip shorts. It is made by International Rectifier and I believe the full number is something like IRF2153. I had these in stock and not sure of which source I had procured them from... It was from one or the other.

Lots of destruction and one really needs a desoldering station to work this. Removal of the blown IGBT's is especially tough. All solder must be removed from the transistor leads AND the thermistor on one of the heat sinks. Once you have verified the leads are loose, one has to rock the heat sinks to get the tabs free. The tabs are NOT soldered! Be careful when restoring to get the thermistor leads started in their holes.

Note: ALL these repair parts were procured from DigiKey.com and Mouser.com. Neither of these places had all, I had to order from both. Mouser had the ceramic resistors.

When restarting this, leave outputs disconnected until it is running again. USE a series 75 watt light bulb in the 120 volt input. ONLY work on the unit using an isolation transformer as a large portion of this is connected right to the power line.

There is a small 15 volt switching supply that comes on first that runs the relay to short out the inrush limiting resistors. With the 2153 shorted as usual, this auxilary supply can't reach voltage enough to turn on the relay. The power for this is supplied through the ceramic resistors.

Hi, if the capacitor has bulged out then its likely to have taken out a fuse on the board, they are not obvious to find as they surface mount them, they look like resistors, often a white body with a number on it eg, 5 for 5amps. With the power off, check around the componets for open resistance, set your meter at 10 or 100 ohms, analogue meters are better than digital for this analysis. Watch out for capacitance as ther could be several hundred volts stored in the circuit.

I have a PMP5000 that I had to resurect. I had to trace out the power supply to repair it.

I can give you hint: First, a small supply runs directely from the line and generates some of the small voltages. While this starts, the main power caps are charged through limiting resistors. The main switcher is brought online and if the power amps acheive balance, then a relay connects the speakers and shorts the limiting resistors.

This is what is in the 5000 and I suspect the 3000 is similar.

In my 5000, there was arcing at one side of the power amps. The board was burned and three power fets fried. Cancer of burned board had to be carved out and traces replaced by hardwiring.
In addition, the limiting resistors were blown open, both main switching transistors were blown and 4 small driver transistors (surface mounted) and several diodes AND a switching regulator chip (surface mounted).all fried/

Hint: When restarting the unit, put a 150 watt light in series with one of side of the power input to limit the current in case you did not get all the dead bodies out.

This is a class "D" amp which drives PCM waves into a filter which is then the audio output. It is much more efficient thaan a linear amp.

I had the same problem with my Saffire: the phantom power voltage quickly drops when switched on, causing the mic to cut out. This problem is common in older Saffires, and is well known to Focusrite support (a modification in newer-production units solves the problem).

The problem is that a tiny 100 ohm surface-mount "chip" resistor in the phantom power circuit fails due to insufficient power-handling capability. (This is "R196" in the phantom circuit.)

The fix is to replace the "chip" resistor with a "normal" 1/2 watt metal-film resistor (with wire leads), mounted upright on the circuit board.

I replaced the resistor myself, following directions (and photos) sent to me by Focusrite Tech Support.

The procedure is somewhat fiddly (a Swiss watchmaker could probably do OK). If you've never soldered before, DON'T EVEN TRY THIS, and if you've never worked with surface-mount components, I would ask your electronics-hobbyist buddy to do it for you.

Here is the procedure sent to me by Focusrite:


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Dismantling the Unit

Remove the 7 screws on the rear panel.
Remove the 4 screws on the underside of the unit.
Lift away the metal cover.
Remove the 4 small black screws securing the MIDI In/Out sockets.
Remove the single screw securing the S/PDIF In/Out sockets.
Remove the two screws securing this PCB to the chassis.
Gently pull the PCB away from the rear panel and move it through 90 degrees towards the front panel.
Place the unit on its front and support the PCB with some suitable non-conductive item.

Modification Procedure

All the components mentioned are located in the same area on the same PCB (see photo).
It is best to remove the coil and capacitor (as shown in the second photo), as this gives easier access to the components.
Remove R196 and measure its resistance. If it does not measure 100 ohms, replace it.
Use a conventional type (100 ohms metal film, .5 or .6 watt) mounted upright as shown in the photo. Before fitting this resistor, check that the three zener diodes DZ11, DZ12 (22v) and DZ9 (3.3v) are OK and have not shorted out. (Diodes are 500mW, 5% tolerance)

Testing units for Phantom Power problems

Connect a condenser Mic or suitable dummy load* to Channel 1.
Engage +48 switch.
Measure the DC voltage between XLR pins 2 & 1 on Channel 2 Mic Input XLR.
Faulty units usually read around +28Vdc and the voltage gradually drops.
Good unts will measure +48Vdc +/- 0.7Vdc.

* Dummy Load for testing: Solder a 20,000 ohm resistor between pin 2 and pin 1 of a male XLR plug and another 20,000 ohm resistor between pin 3 and pin 1 of the same XLR plug.




Here are the photos:












My Saffire has worked perfectly since I replaced the bad resistor.

Good Luck!

Ken

You can not find any schematics for the Magellans.  The schematics are classified.  Even when repairing GPS's for Magellan we didn't receive full schematics.  If your talking about the RF cable connector on the I/O Board (the board attached to the rear housing), then it's an easy solder fix.  For the capacitor/resistor:  I'm not sure where you found the capacitor origin, but if it's black with four legs coming off and parallel with the IC then tell me and I'll msg you back the rest.