Layout of m200 circuit board

SanDisk Sansa m200 Series MP3 Player Circuit Board Layout (bottom) 

Bottom of Board

  1. Headphone Connector
  2. USB Connector
  3. Battery negative connector spring
  4. Power On/Off Switch
  5. Volume Down Switch
  6. Philips TEA5767 FM radio
  7. Volume Up Switch
  8. DM 621 Battery
  9. Socket for Flash Memory (not shown)
  10. Battery positive connector spring
  11. 1 Meg RAM
  12. Main Processor - Telechips TCC 770
  13. TI Stereo Amplifier
  14. Hold Switch
  15. Microphone

Many of the components were covered with black foam pads which were removed for the photo.

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Top side of m200 Circuit board showing the LCD Display and the diaphram type switches.

Front of Board
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Version

  The revision number on the card.
Must match the firmware level on the unit.

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Memory Card
Memory Card

Note that it is made by Samsung.

This is a 1 Gig chip, the only physical difference from a 512 is the lettering on the chip.

No components are user servicable except the flash memory card

Thanks to “turbodog” on the anythingbutipod forum for information on the chips.

http://www.anythingbutipod.com/forum/showthread.php?t=755

Message Edited by Walt-n-Florida on 04-05-2008 09:37 PM

Message Edited by Walt-n-Florida on 04-05-2008 09:39 PM

Message Edited by microsansa on 04-27-2009 07:29 AM

The DM 621 battery soldered on the m200 circuit board is to keep the Real Time Clock (RTC) alive during power off.  The clock is only used to check expiration of timed items such as borrowed books from libraries, etc.  Since the m200 series is an “economy” model, SanDisk chose not to include a clock in the display.

The chipset also supports a recovery button, but again, SanDisk left that off.  Since the m200 is no longer manufactured, there’s no hope of having it added.

Awesome addition. Thanks go to the original poster.

so, whats the possibility of adding a bigger memory chip to the board?

Re: Adding a bigger memory chip to the m200

I did just that.  I bought a m230 (locked up) and a m240 (broken display) from Ebay for $6.99 shipping included. Took the memory chip from the m240 and plugged it into the m230.  The m230 has a version 2 board and the m240 had a version 1.  The m230 is now a m240 version 1.  The version (firmware) followed the memory chip. Can’t guarantee this will work for everyone, but it worked for me. 

Incidentally, the sound has gone out on the second circuit board, so I now have two non-working units. If you buy a “locked-up” unit, chances are very good it is the memory card.  The m230 would not power on and was not recognized by the PC, but it works great with the m240 memory card (except for no sound).

Very interesting thread, and beautifully done. Thank you.

@walt_n_florida wrote:

No components are user serviceable except the flash memory card

Do you know if the “8. DM 621 Battery” is replaceable?

I have a M200 series and it is giving me the “Sync Notice” until I reload the new firmware.  I just noticed the other day that the battery was going low, and when I changed it I started getting the “Sync Notice” again.  I think that the internal battery might be dead and causing the error. 

Also if the battery is replaceable, are there any tricks or special tools needed to take the case off? 

Thanks in advance for the help!


NKY wrote:

Do you know if the “8. DM 621 Battery” is replaceable?

Also if the battery is replaceable, are there any tricks or special tools needed to take the case off? 


I doubt you can find a replacement battery.  I have tried several times and failed. It is a simple button lithium battery as in watches, but it must be rechargeable.

To open the cover, you may be able to just pull it apart, if not, insert a flat blade in the seam around the edge and pry it.  You may scratch the case doing this.

I doubt you need a new battery.  It should recharge from the AAA battery.  Don’t let your battery get below 1/2 on the display.

A search on Google for “m200 sync notice”, “m230 sync notice” etc for m240 & m250 turns up lots of hits concerning Rapsody and lots of devices being fixed by formatting. 

I had the error once myself when I first got the m250 but don’t remember what I did to fix it. I do know that formatting (both MTP and MSC) cures lots of ills.

Edited to remove web addresses above.  (No personal web space)  Walter Moore   01-11-2010

Message Edited by Walt-n-Florida on 01-11-2010 10:15 AM

Great information and especially at those links, and thanks again. After reading your own page on the m200 I realize more than ever how necessary it is to be careful with these units. Don’t just stretch and push them to the limit unless you don’t mind dealing with having a piece of junk on your hands. I’m going to try to give the problem areas a wide berth, such as letting the battery get too low (and I do use NiMH, good ones, though from now on!!) and not filling the capacity (i.e. MB’s) anywhere very near the 2 GB of the m250.

I’ll drop a little piece of trivia here: I didn’t have the advertized Stopwatch function until I turned on Smartmenus. Once I did that, the Stopwatch function was there, even after turning off Smartmenus. This is with the latest 4.x firmware.

Message Edited by Muse on 05-14-2008 09:44 AM

Message Edited by Muse on 05-14-2008 09:47 AM

Walt, your http://www.tnni.net/~walterjmoore/m250/formatting.htm link comes out screwy, at least for me. The text is displayed in a column that’s around and inch wide. If I copy and paste it into a document, it’s nicely formatted, however. I’m using Firefox on XP Pro.

Message Edited by Muse on 05-14-2008 11:59 AM

I don’t know why the web page came out formatted like that for you.  I used Dreamweaver MX 2004 to create it and it has a left margin of 50 and margin width of 700.  I have 3 PC’s and they work fine, but all are running XP Home with IE7. Firefox doesn’t work well with dialup so I gave up on it.

I noticed you are using NiMH batteries.  SanDisk reccomends using only Alkaline batteries.  The rechargeables don’t have quite the power and their power diminishes with each charge, so after a few months, you are running on half charge at best. 

I’m pretty into rechargables, and in fact I keep computer records of my batteries’ capacities. My La Crosse BC-900 charger gives me readouts of the capacity and state of charge of the batteries. I have many, but recently bought some Rayovac Hybrid NiMH’s, and I’m sure the capacity is over 750 mah. I haven’t tested them yet. I have a lot of alkaline too, but I’m not inclined to use them for this sort of application. So far, my m250 has worked well with NiMH’s and they’ve been anything but top of the line. I’ve been using the ones that came with the La Crosse charger. They’re OK, but nothing great, and in fact one died. :robotsurprised:

Now, I’m going to stick to the Rayovac’s and keep an eye on them.

My experience indicates that NiMH’s do better than you think. Especially with a good charger, they can retain their capacity for a long time, and like I say, I keep records of how they’re doing. I think that based on what you say, the main thing is to not let the cells get near exhaustion in the unit.

I have a feeling that these Sandisk people don’t know their own equipment all that well considering they have 4 distinct lines of m250’s. Your experiments indicate that they didn’t test and redevelop the product sufficiently before putting it on the market, too. What firmware do you have (i.e. to which product line of the 4 do your comments refer)?

Message Edited by Muse on 05-15-2008 06:00 AM

Hello Muse,

 I did the voltage tests on both a m240 and m250.

I have a Version 1 m230 with a cracked display.  Since it wasn’t useable (I could load and listen to music, but couldn’t see what I was doing, it was all “in the dark”) I tried changing the firmware version to Version 2. It locked up.  I have a Version 2 m240 with no sound output. It’s not the headphone jack, the chip has no output.  I went through 3 m250’s.  I filled the first to capacity to see what it would hold.  It started locking up and then every time I pressed the menu button, it did an immediate power off, no save settings, no delay. Returned it (Circuit City).  Second one, after exhausting power on the battery for the tests, locked up and wouldn’t power off.  Had to remove the battery.  It would then display the title of a song, wait a second and display the title of the next song, continuing until I removed the battery.  All buttons were inoperable. Third one worked great for a couple of weeks, then started losing it’s place in the playlists every 30 or 40 songs and would restart at number 1.  I returned it and now have a Sansa Clip.  It has a limit of 250 songs per playlist (dumb) but I can live with that if it doesn’t lock up. 

Anyway, I no longer have a working m200 device, just a box of junk parts.  This will probably be my last post on the m200 forum, but I will leave my website up for a year or so just in case.

Walt,

My first m250 was a refurb through buy.com. It wouldn’t remember settings after a power down and I posted here and at anandtech forums. I made contact with Sandisk and managed to get the unit replaced, although they don’t have a refurb program (that was done outside of them). I was offered a Clip as a free upgrade but turned it down because it doesn’t use AAAs (has a rechargable lithium, which I figure would be a tough if not impossible replace). I knew nothing else about the Clip, but based on the fact that it can’t use quick replacement batteries I figured the m250 was better for me. I suppose I’m going to have issues, probably major issues and ultimately some disappointment with the m250. I just bought another, this time retail factory sealed, to have a backup in the hopes it will have version 4.x firmware or at least a different one than my 2.x m250, which has only very slow FF (I listen to a lot of 3 hour MP3s and 10 to 1 FF is a major problem). [Edit 5-26-09: As luck would have it, my next unit was version 4.x firmware. It does support accelerated FF/REW, although the algorithm can be very frustrating (almost no effect transitions into quicker and then very soon into astronomical FF/REW, and with some files an inexplicable return to the beginning of the file when removing your finger from the button)]

I also bought 2 m250s as gifts, and I suppose the recipients will one day pretty soon be tossing them in the trash, given your experience.

Thanks for keeping that info up on the web for a while. I’ll see if I can save it to my machine when I get back home (I’m away for the weekend).

Message Edited by Muse on 05-17-2008 10:26 AM

Message Edited by Muse on 05-26-2009 11:46 PM

Message Edited by Muse on 05-26-2009 11:46 PM

Walt:

RR?

Laird 

Walt, even if your m250s don’t work, maybe you can use them as radios. The FM in the m250 is by far the best I’ve ever experienced in a small form factor portable. It’s excellent, sensitive. Doesn’t support the EQ functionality, however.

Hi NKY and Walt-n-Florida,

The DM 621 KORCHIP is in fact a “starcap”,

see http://www.51buyic.com/admin/uploadfiles/200866112036625.pdf

(in Chinese ?)

It looks like the DM 621 is "621 Type (Φ6.8×2.1mm) "

and the only one of that size is:

SCDM2R5334 2.5V 0.33F 100Ohm @ 1kHz (Φ6.8 × 2.1mm)

(This is just from a Google of “DM 621 korchip” and translating the resulting pages)

CM

Walt, when I click on the links I get the message, “can’t find the page”, I am using Firefox 3.5 on Windows XP Professional.

Sorry for the wrong web address.  I changed ISP and didn’t get around to changing everything.  It is now corrected. Don’t know how much longer that will be valid.  Am planning to change again next month.

I no longer have personal web space, so have removed references to my website in previous posts.

I enjoyed it while it lasted.

Message Edited by Walt-n-Florida on 01-11-2010 10:17 AM