Sega Nomad help? It's dead!

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I've tried a few Sega forums without any luck, so I'm turning to you guys. I bought it broken, nothing happens when you turn it on. I've tried with batteries and the adapter, which I've verified is working and still no luck.

I am getting power through the dc port to and through the switch, but nothing to the voltage regulator. I'm testing as follows, the middle pin is ground, left pin should be 12v-13v in and the right pin should be 5v out, but there's nothing on either of the outer pins. I pulled both capacitors near the power port and they measure just fine.

I can't find a Nomad schematic and I'm not sure where to go from here. I do have a power probe, which I'm going to hook up and send 13v into the regulator just to see what happens. Any thoughts before I do that?
 
going to hook up and send 13v into the regulator just to see what happens. Any thoughts before I do that?

without a schematic, I would be wary of send voltage into anything

maybe I would get a working one and measure what is going into/out of said component and then replicate on the broken part and see if it works but without verification you are taking all kinds of chances of really screwing something up bad

good luck
 
Should be a surface mount fuse between the DC jack and the 5v regulator.

Don't just go throwing voltage at stuff, unless you like the idea of dead hardware.
 
I found this.......

So, somebody recommended me this forum to ask for help.

Right now I've got two Nomads and to Game Gears that have issues.

The GGs look like the typical capacitator-replacement job (problems fit the common descriptions to the letter) - which I'll find out as soon as I have both of my Nomads fixed and ready!

Here's the story (copy & pasted from another forum):

Well, I finally bought TWO Nomads from the US, since we poor Europeans were left out back in the day.

Not wanting to pay too much, I got me two faulty ones:

- Number one had a faulty DC-power jack on arrival which needed replacing badly.

The Sega Nomad's power jack is identical to the PS One's and PS2's and still available to order, so no worries if you need one! (I even got me one spare just in case.) This Problem is now fixed!

- Number one will power on, but there's only a white-grey/black screen and after a while some "crunchy" noises from the audio. Nothing else happens. The screen brightness can be changed as well as the audio level via the wheel potentiometers, but that's it.

Same story if I connect it to a television via AV-port - including the "crunchy" noises. Interestingly, the television will switch to the correct AV-channel if I turn the Nomad on!

Contacts of the cartridge slot have been thorougly cleaned and the cable (which connects the two halves of the Nomad) has been checked - to no avail.

Since my second Nomad mostly works (apart from the "white screen" issues, see below) I switched its second "half" board with number one's and, voila, the handheld comes alive!

The four capacitators (1x 100uf, 3x 47uf) on the board have been replaced and the problem persists - exactly as before!

Any idea what's the problem with the board and how to fix it?


- Number two will power up fine and audio will play as it should but the screen is completely white. No wonder, since the wheel of the brightness control is gone! Ripped out, broken out, no idea - it's gone! (The lower half of the potentiometer is still there.)

The handheld works perfectly (audio and video) if connected to a television via the AV-port.

Alas, the wheel potentiometer (47 kOhm with 4 pins) is a rare(r) type I have not encountered before (most common types are for audio jacks with 5 pins and only at 10-20 kOhm).

I've actually come across a possible replacement!

www.debonelectronics.com/sell-db_06g1_thumbwheel_potentiometer-637982.html

Any idea where I can get a real replacement? It's (supposed) to be identical to the Game Gear's one, but where to get one? (Ordering 1000 on a whim does not seem to be the best solution.)

Note: Yes, I could do a lcd screen-mod which would render the brightness control issue obsolete. But first I want two working machines in original condition before I go ahead and try that.

Apart from that, any advice is appreciated! Please help!

If you need any pictures of the two handhelds, just say so!

Thank you!

http://www.smspower.org/forums/14536-SegaNomadHelpGameGearLater
 
I really appreciate you taking time to research it for me, but it didn't really apply to my situation. I really wish I knew someone else with a working Nomad so I could compare readings with mine. If I knew exactly which pin of the regulator was the input side, applying 12v there shouldn't cause any problems whatsoever, it's the same as if it was getting 12v like it's suppose to, it would just back feed to where the actual problem is and then stop.

I thought for sure the left pin of the regulator was input, middle was ground and right was output voltage, but without knowing for sure, I don't want to do anything.

I can't believe the lack of info on this system.
 
I read the whole thing and there is some interesting stuff about bad connections on the one chip resulting in the white screen problems.

On yours I would trace the power after the switch and see where it goes. Does the Nomad take the same power supply as the gamegear? I found schematics for the GG.

Here is some info I found on the Nomad.

http://console5.com/wiki/Nomad

Gamegear info.

http://gamesx.com/wiki/doku.php?id=schematics:console_related_schematics

This is an interesting one about a bad voltage regulator. This might be your problem.

http://forum.digitpress.com/forum/showthread.php?113516-Replacing-a-Sega-Nomad-s-Voltage-Regulator

This is supposed to be the correct part VR.

http://uk.farnell.com/national-semiconductor/lm1117mp-5-0/v-reg-ldo-5-0v-1117-sot-223-3/dp/9778209

Tech sheet

http://www.farnell.com/datasheets/1685500.pdf

Texas-Instruments-LM1117MP-5.0-NOPB.jpg


LD1117-pinout.jpg
 
It sounds like the voltage regulator is a common problem. here is a Youtube vid.

 
That's the main video that made me think it was the regulator, but I'm not getting power into the regulator. There can't be that much between the switch and regulator but unfortunately I just don't see anything that could be the problem. I just wish there was a schematic for it, I'd feel much more comfortable with a diagram.
 
Well whatever you do don't feed it any more than 6 volts. The regulator is a 5 volt.

I would take my test meter and follow where the power from the battery comes in. There has got to be a fuse of some kind in circuit.
 
That's the main video that made me think it was the regulator, but I'm not getting power into the regulator. There can't be that much between the switch and regulator but unfortunately I just don't see anything that could be the problem. I just wish there was a schematic for it, I'd feel much more comfortable with a diagram.

There is almost always a fuse between the switch and regulator or very near.
 
Should be a surface mount fuse between the DC jack and the 5v regulator.

Don't just go throwing voltage at stuff, unless you like the idea of dead hardware.

^^^This is what you are looking for. Might even be a zero ohm resistor but that is on tv's and such.
 
Fixed!

I borrowed a working Nomad and started tracing out the power circuit. I found I was not getting power from the positive side of the capacitor to the voltage regulator. Basically the power flows from the DC port to the switch, through the switch (when switched on) to a capacitor leg and through that leg to the voltage regulator.

I have a tool called a Power Probe that allows me to give voltage to a component with the push of a button. Since I knew what side of the regulator needed 12 volts I used the Power Probe to give it 12 volts and the system came to life. Using my multimeter I could see I had 12 volts up to the positive leg of the capacitor but for some reason not out of the leg. I had continuity all the way from the switch to the voltage regulator but a major voltage drop at the positive leg. I ended up scraping away some of the green solder mask and Bridging the leg to the bare spot so I could get the voltage to flow through it. There are three contact points on the power switch the third one carries the voltage through when you switched it on. I put a jumper wire from that terminal to the positive leg just to make sure I had voltage. It probably wasn't needed but I wanted to be sure.

Now that it's working I still have to fix the DC power port because it's loose internally, but that's a much simpler fix since it's only 3 points to desolder/solder.

Maybe just maybe this will help somebody in the future.
 
I forgot to mention that I replaced the capacitor mentioned above (pretty sure it's 100uf 25v) with a new one and left the legs long so I could solder to the leg. Luckily where that cap sits, the case has plenty of room to allow it to stick up. The old cap tested fine, but I needed to be able to solder to the + leg since power wasn't getting there.
 
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