Replacing a Sega Nomad's Voltage Regulator.

[jb143]

Does anyone happen to know the internal regulated voltage of a Nomad? I'm assuming it's 5V but I'm not sure. My Nomad had a fried regulator when I got it and I thought I made a work arround. But now I found it won't work on fresh batteries...only half dead ones...which usually isn't a problem with the Nomad but now I'd like to use an adapter for obvious reasons.

I want to attemp to replace the regulator so any help will be appriciated. Extra points if anyone actually measures the voltages. I'll be sure to post my results here so others can make the same repairs. Thanks.

[FABombjoy]

Probably 5v, but you might be able to determine it like so:

1 - Locate the datasheet for another component
2 - Verify continuity between VCC on that component and the output leg of regulator
3 - Per datasheet, VCC for component is regulator output voltage

[SnowKitty]

Does anyone happen to know the internal regulated voltage of a Nomad? I'm assuming it's 5V but I'm not sure. My Nomad had a fried regulator when I got it and I thought I made a work arround. But now I found it won't work on fresh batteries...only half dead ones...which usually isn't a problem with the Nomad but now I'd like to use an adapter for obvious reasons.

I want to attemp to replace the regulator so any help will be appriciated. Extra points if anyone actually measures the voltages. I'll be sure to post my results here so others can make the same repairs. Thanks.

i'm pretty damned sure it's +5V dc.

[jb143]

I'm almost positive too...I just havn't been able to cross reference the regulator. I jumpered the input voltage to the output of the regulator but any voltage that's too high it just won't work...and I disconnect for fear of burning something up.

[FABombjoy]

Wait... you jumpered the regulator input to the output?

uh...

[jb143]

Yes...to verify operation. It was completely dead before that. Don't worry...I didn't plug in an adaptor.

[FABombjoy]

I'm still not too clear on what you were trying to accomplish, or where the fear of burning something up came from if it wasn't plugged in :)

[jb143]

Other than a very quick flach of the LED when you turn it on or off it was dead when I got it. There wasn't any noticible problems so I got out the ole logic probe and multimeter. Everything before the regulator had power...everything after, not so much. I powered the backlight seperatly and it worked so I knew no voltage was getting there. So then I just routed power arround the regulator and voila...as long as the batteries were just dead enough it worked great.

As far as not wanting to burn anything else up. I really have no idea what happens to TTL or CMOS with overvoltage, or how long the smoke will stay in them. Why take my chances.

I'm thinking that the previous owner plugged a reverse polarity or AC out adapter into it and fried the reg so they tossed it in the box o' game stuff that I bought from them.

[jb143]

I've verified 5V...now I just need to find a sutable replacement for the regulator. It seems to have a different pinout than most I've seen...although I'm pretty sure I could solder an LM7805 in there.

[jb143]

I finally got around to replacing the regulator and it works great now. I've had several people ask me about this so I figured I'd post what I did. It was pretty simple to do and took me about 15 minutes to do. Please ask any questions becasue I'm sure some of this will need cleared up a bit.

I could never find an exact replacement so I used part number MC78M05BDTRKG - 68cents from digikey.com. I mainly used this becasue it's what I had access to and it had a higher current rating than others. It's a "D-PAK" package so it's quite a bit bigger than the original regulator making it easier to work with but it's still an SMT part making is small enough to fit in there. I'm pretty sure any +5V linear regulator will work though.

The first step was removing the old regulator. I used a hot air gun but I realise most peole won't have access to surface mount rework equipment so heating with a soldering iron and prying the chip off will probally work just as well. Then clean the pads up as much as possible making sure that there's no solder shorting them out.

As far as clearance goes the only thing you need to worry about is the plastic circle on the other half on the Nomad. I had to relocate my regulator becasue I couldn't get it closed back up the first time.

I then soldered a wire to each of the legs of the regulator. One was Vin the other is +5V out. These should be marked on your regulators datasheet. +5Vout n the board is the larger pad where the regulator used to be, so the other end of that wire should be soldered there. For Vin I soldered it to the point where +V comes off the power jack.

To help dissapate heat I decided to solder the regulators ground tab right to the circuit boards ground plane. To do this I sanded away a small square of the boards coating near the edge of the board making sure the plastic circle I mentioned above would clear it. This left a square of exposed copper roughly the same size as the regulators ground tab. Be sure to clean off the dust made from sanding.

Since the ground plane will dissapate heat, you'll probally need to hold your iron on the copper pad you just made for qute a while in order to heat it up. Once it's hot enough, add a layer of solder and then place the regulator down. Again, it's probally going to take a bit before the solder takes.

If all goes well you should now once again be able to enjoy handheld Genesis goodness.

[phreak97]

if anyone has a nomad that doesnt work, ill pay $5 for it :P


nice work on that repair.. though i wouldnt have put new batteries in it at all.. six aa batteries puts it at 7.2V with rechargables or even 9V with alkalines.. either way is a bit too toasty warm for 5v ICs.. the smoke is built in for a reason, it needs to stay in there.

[jb143]

nice work on that repair.. though i wouldnt have put new batteries in it at all..

I never put in fresh batteries...I just tried some that weren't quite dead enough to get 5V at first...and once it wasn't working I turned off power immediatly.

All is good now and I've testing with rechargeables and a power supply.

[jb143]

Here's a picture that might help anyone trying to make this repair.

http://i260.photobucket.com/albums/ii12/jeremy_burk/5vreg.jpg

It's basically a surface mount version of a regular 7805 regulator that you can usually get at Radio Shack.(If you find room in the Nomad then you could probally use one of those)

I'll try to add actual photo's of my repaired board this weekend to show where everything goes.

[phreak97]

ah ok, all good then:)

[raylydiard]

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

exact replacement

[jb143]

Yup...that looks like the part I was looking for several months ago. Mine has been working fine and the repair has held up quite well.

btw...the digikey part number for that part is LM1117MP-5.0CT-ND

[raylydiard]

hi did you make a photo of your repaired board


Here's a picture that might help anyone trying to make this repair.

http://i260.photobucket.com/albums/ii12/jeremy_burk/5vreg.jpg

It's basically a surface mount version of a regular 7805 regulator that you can usually get at Radio Shack.(If you find room in the Nomad then you could probally use one of those)

I'll try to add actual photo's of my repaired board this weekend to show where everything goes.

[jb143]

hi did you make a photo of your repaired board

Hmmm...I don't think ever did. It wasn't too pretty but it's worked fine for these past 2 years. If I would have been a bit more patient and found the exact regulator you mentioned above, I would have gone that route.

If you're interested in seeing it though, I'll try to remember to snap a picture this weekend.

[raylydiard]

thanks ?

[hardgb]

Hmmm...I don't think ever did. It wasn't too pretty but it's worked fine for these past 2 years. If I would have been a bit more patient and found the exact regulator you mentioned above, I would have gone that route.

If you're interested in seeing it though, I'll try to remember to snap a picture this weekend.

---------------------------------------------------
I'd much rather you send a photo as he did the procedure, so that you would help me a lot.
:help:

[hard]

I wonder how you put MC78M05BDTRKG in sega nomad.
Please I ask that you put a picture or photograph of what he did.
I need this information to bring my Sega Nomad for life.
(I am brazilian)
:oops:

[cleilton]

Jb143, you're awesome, my sega nomad is with this problem.
You must have had a lot of work to find and fix the defect.
I ask you please help because I am not able to understand how to weld the voltage regulator (MC78M05BDTRKG or even another)
I will be waiting for your help.

[RetroGameTech]

I just wanted to say a massive thanks to jb143 for all the info posted in this thread :hail: . Thanks to you my Nomad is now working again! I made a quick video to show how I repaired mine so hopefully others can use it to help fix their own. Details about parts etc are in the video description.

http://www.youtube.com/watch?v=SDo3o2no770

Thanks again, jb143! :cheers:

[xelement5x]

Great video! This is an awesome piece of info to have out there.

[jb143]

Hey, thanks for putting together that great video. I tried to take a picture way back then but my old camera was horrible at close up shots. Your video is way better than my blurry pictures ever could be. :)

[that1crzywhtguy]

I finally got around to replacing the regulator and it works great now. I've had several people ask me about this so I figured I'd post what I did. It was pretty simple to do and took me about 15 minutes to do. Please ask any questions becasue I'm sure some of this will need cleared up a bit.

I could never find an exact replacement so I used part number MC78M05BDTRKG - 68cents from digikey.com. I mainly used this becasue it's what I had access to and it had a higher current rating than others. It's a "D-PAK" package so it's quite a bit bigger than the original regulator making it easier to work with but it's still an SMT part making is small enough to fit in there. I'm pretty sure any +5V linear regulator will work though.

The first step was removing the old regulator. I used a hot air gun but I realise most peole won't have access to surface mount rework equipment so heating with a soldering iron and prying the chip off will probally work just as well. Then clean the pads up as much as possible making sure that there's no solder shorting them out.

As far as clearance goes the only thing you need to worry about is the plastic circle on the other half on the Nomad. I had to relocate my regulator becasue I couldn't get it closed back up the first time.

I then soldered a wire to each of the legs of the regulator. One was Vin the other is +5V out. These should be marked on your regulators datasheet. +5Vout n the board is the larger pad where the regulator used to be, so the other end of that wire should be soldered there. For Vin I soldered it to the point where +V comes off the power jack.

To help dissapate heat I decided to solder the regulators ground tab right to the circuit boards ground plane. To do this I sanded away a small square of the boards coating near the edge of the board making sure the plastic circle I mentioned above would clear it. This left a square of exposed copper roughly the same size as the regulators ground tab. Be sure to clean off the dust made from sanding.

Since the ground plane will dissapate heat, you'll probally need to hold your iron on the copper pad you just made for qute a while in order to heat it up. Once it's hot enough, add a layer of solder and then place the regulator down. Again, it's probally going to take a bit before the solder takes.

If all goes well you should now once again be able to enjoy handheld Genesis goodness.

I am hoping—as I know this is a very old post now—I can get some help on my nomad.

After a screen mod like found on nobitleftbehind, my regulator stopped working. I replaced it for a NTE 960 and when the replacement screens driver board is unplugged I get 5v out of the regulator.

This is where things get strange. When I plug in the lcd driver board, the voltage coming out of the regulator dips below 2v and the low batt light shines as if to mock me.

I'm confused, want to save my nomad, and hope someone out there can offer some wisdom.

Thanks in advance.

[phreak97]

Can you post a link to the replacement parts you used? The lcd driver may be wired incorrectly or faulty, if you turn on the nomad without the driver board can you hear the game playing?

A photo of your setup would help too

[that1crzywhtguy]

Can you post a link to the replacement parts you used? The lcd driver may be wired incorrectly or faulty, if you turn on the nomad without the driver board can you hear the game playing?

A photo of your setup would help too

Regulator: http://www.alliedelec.com/nte-electronics-inc-nte960/70215297/


Screen found here: https://nobitleftbehind.wordpress.com/store/ and is just like this: http://pages.ebay.com/link/?nav=item.view&id=331040572849&alt=web

I have had the speakers unplugged while I've been testing. When I get home tonight I will try to power up with the driver unplugged and see if I hear audio.

I am including some pictures as well. Thanks for the help.


https://app.box.com/s/yiytjs1mvij2ay8vv59j8nvw9olbpfjo

https://app.box.com/s/206bwr9t2fvnu9ah9fdwgc26qvfxk9hx

https://app.box.com/s/2rlak303l1v5pzvyimrp6v6ihirjiu78

https://app.box.com/s/goqxvbsmjcl4655uc2we2kvc40gfxwut

Thanks!

[phreak97]

Alright, what's the red jumper wire on the driver board doing?
I think the driver board is expecting 12vdc, you might need to rework it a bit to accept 5v instead.

[that1crzywhtguy]

Alright, what's the red jumper wire on the driver board doing?
I think the driver board is expecting 12vdc, you might need to rework it a bit to accept 5v instead.

The red jumper on the driver board addresses just that, it is skipping the 12v to 5v dc-dc converter.

[that1crzywhtguy]

if you turn on the nomad without the driver board can you hear the game playing?

Update, with the driver board unplugged I can hear the game audio. So that is certainly a good sign that the system is not toast...

Maybe the lcd or driver board is toast, certainly possible...

[Niku-Sama]

What's going on with that voltage regulator?
The 7805 looking one? I only see 2 wires going to it

[phreak97]

The centre pin is soldered to ground on the pcb.

Sounds like theres a problem with the driver board for sure. Triple check the dc-dc bypass

[that1crzywhtguy]

The centre pin is soldered to ground on the pcb.

Sounds like theres a problem with the driver board for sure. Triple check the dc-dc bypass

I think that jumper was done poorly maybe, (I purchased it pre jumpered) as when I desoldered it and resoldered it, now the system works (I can hear the speaker playing game audio and the board is receiving ~5V) with the driver board still plugged in. The screen still does not function however. I'm thinking maybe something shorted out, which is a little surprising since it did work initially, however it certainly isn't working now.

Another thing that I find peculiar, is that when I plug the av out through a genesis 2 RF cable and switch the nomad on, the TV goes black. No more white fuzz but also no game sound or display, also I still hear the nomad speaker playing audio. This make any sense?

Thanks

[phreak97]

I noticed the track on the pcb going to the composite video output has been cut, did you do that intentionally?

[that1crzywhtguy]

I noticed the track on the pcb going to the composite video output has been cut, did you do that intentionally?

alas, I did not... I originally had the composite out wire soldered there and the pad got pulled off... I saw others who had done this mod had their's soldered to the pin right above it, so I attached mine there. I didn't think it would effect the nomad's ability to send an AV signal out of that port though, am I wrong? I get no audio or video out of that port.

[Niku-Sama]

The centre pin is soldered to ground on the pcb.

Kinda my point, looks like you have input and ground and that's it. Or is that side output, either way ground and only one other connection

[phreak97]

alas, I did not... I originally had the composite out wire soldered there and the pad got pulled off... I saw others who had done this mod had their's soldered to the pin right above it, so I attached mine there. I didn't think it would effect the nomad's ability to send an AV signal out of that port though, am I wrong? I get no audio or video out of that port.

Yeah that broken trace takes video to the av connector, you'll have to install a tiny jumper wire from the through-hole to the pin where you have the wire attached.

[phreak97]

Kinda my point, looks like you have input and ground and that's it. Or is that side output, either way ground and only one other connection
Its just a bad photo angle, it's connected with two green wires. If it was wrong there'd be no sound either. We've solved the power issue anyway, it's just missing video now

[that1crzywhtguy]

Yeah that broken trace takes video to the av connector, you'll have to install a tiny jumper wire from the through-hole to the pin where you have the wire attached.

Darn I was worried about that. Which through hole? I'm including a close-up. Do I solder a jumper from the little hole between the text TP244 and TP241 to the pin?

Thanks

https://app.box.com/s/p5prucd1ylp51kr6izf6cbluqnlxtrxw

[phreak97]

Yup, right in the middle of the three 4s

[that1crzywhtguy]

Darn I was worried about that. Which through hole? I'm including a close-up. Do I solder a jumper from the little hole between the text TP244 and TP241 to the pin?

Thanks

https://app.box.com/s/p5prucd1ylp51kr6izf6cbluqnlxtrxw


Nevermind lol. I just tried it and now I have video and audio out through the RF switch... So that problem is all sorted. Now I've just gotta get this screen sorted out. Not so sure what could be wrong with the driver or how to troubleshoot it now...

[phreak97]

Oh so still no video from the lcd?

[that1crzywhtguy]

Oh so still no video from the lcd?

THAT DID IT! This puppy is up and running with my beautiful new lcd! Thank you SO much for all your assistance, it is deeply appreciated!

[phreak97]

No problem at all! Glad I could help:D

[marcusrushy]

hi there. my nomad just has a white screen when turned on. will replacing the voltage regulator help. it looks like it has blown.

[jb143]

Read the voltage from the regulator. It should be 5 volts. I wouldn't imagine that's the issue if the screen is lighting up though. Do you get audio? Or do you have an AV cable to connect it to a TV?

Maybe someone who has cracked open their Nomad more recently than 6 years ago can chime in. ;)

[Splosion]

I appreciate this is probably a longshot, but jb143, do you have the partial schematic you mentioned in this thread (http://forum.digitpress.com/forum/showthread.php?108832-Nomad-Issues-It-won-t-turn-on)?

I've been trying to follow the voltage through as it doesn't seem to get to the Vin on my regulator, and it might be easier to pinpoint say, more obvious points to check rather than many hours of trial and error. That is, if you still have it :)

[jb143]

I appreciate this is probably a longshot, but jb143, do you have the partial schematic you mentioned in this thread (http://forum.digitpress.com/forum/showthread.php?108832-Nomad-Issues-It-won-t-turn-on)?

I've been trying to follow the voltage through as it doesn't seem to get to the Vin on my regulator, and it might be easier to pinpoint say, more obvious points to check rather than many hours of trial and error. That is, if you still have it :)

I probably do have that somewhere, maybe, but not entirely sure where, nor do I even know when I'd get a chance to look. If I ever do run across it I'll be sure to snap a pic and add it here. I'm not really sure why I never did back then

It's been a long time since I worked on any of this stuff but I seem to remember the + voltage from the batteries going to the backlight first before the regulator. So the backlight gets full voltage and the rest gets +5 from the regulator. That should be easy enough to test. Or maybe I'm remembering the Lynx...as I was working on one of those around the same time. Again, maybe best for someone else to say for sure since these memories are running on fumes.