There are different versions of the YH-920 and YH-925 on the market. They come branded either as a "Samsung Yepp" or "Samsung Napster". On the back side, they are labelled either as "YH920GS/DXN" or "YH920GS1/ELS". This seems to be region specific. At least two different PCB revisions exist, one is labelled "YH-920 (REV 1.0) 2004.06.08", the other one "YH-920 (REV 2.1) 2004.09.01". The YH925 has a version specific to Canada without Radio (YH925GS). There are also different versions with different lables ("Yepp", "Napster", or just "DDigital Audio Player YH-925).
The hardware between YH925 and YH920 is mostly the same. The only difference is the display, and apparently the presence of a radio.
Parts List for both PCB revisions:
- CPU: PortalPlayer PP5020D-TF
- RAM: Samsung K4S561632E-TC75 (32MB SDRAM), see http://www.datasheetcatalog.net/de/datasheets_pdf/K/4/S/5/K4S561632E-TC75.shtml
- Flash Memory 4Mbit: Macronix MX 29LV400 TXEC-70, see http://www.macronix.com/QuickPlace/hq/PageLibrary48256F55002C90A5.nsf/h_Toc/75d338438656550a48256f5500408bf7/?OpenDocument
- LCD: 160 x 128 (YH920: Greyscale; YH925: Color), Models unknown
- LCD controller: same controllor as Iriver H10 20GB/Iaudio x5 and other target (Renesas HD66773,datasheet)
- Audio: AKM AK4537VN, see datasheet
- Power Manager and Battery Charger: Linear LTC3455, see http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1037,C1078,C1583,P2447
- Hard Disk: 20 GB 1.8 inch, Toshiba MK2004GAL
- Connector for USB and chargers: as specified in TTA standard TTAS.KO-06.0028/R2, see http://www.tta.or.kr/include/Download.jsp?filename=stnfile/TTA-0044.pdf
For PCB rev. 1.0, you will find an additional power distribution switch IC on the top side of the PCB:
The FM Tuner chip is optional, is comes soldered as a small PCB together with a few additional resistors/capacitors on top of the main PCB:
The original firmware, loaded from the first FAT32 partition of the hard drive, is in .mi4 format (see http://daniel.haxx.se/sansa/mi4.html
for details). It is located in C:\SYSTEM\ . There are at least three original firmware versions named either "FW_YH920.mi4" or "PP5020.mi4", one dated 31.7.2004, another one dated 24.09.2004, and another one dated 28.1.2005.
A copy of the original flash bootloader is available on the hard disk as file C:\SYSTEM\PARMS\BL_YH920.rom . Not surprisingly, different versions of bootloaders exist. Firstly, they differ by version number, showing either "BootLoader ver.1.05" or "BootLoader ver.2.05" in the splash screen. Secondly, they differ by branding, one showing an animated Samsung logo, and another an animated Napster logo.
However, it is not fully clear yet which PCB revision / bootloader / firmware combinations are allowed. For example, a Napster branded device with PCB rev. 2.1 works perfectly with a Samsung branded bootloader ver 1.05 and firmware dated 28.01.2005. As can be seen from several user complaints in various forums, it seems that many of the faults seem to stem from incompatible combinations, although the hardware is 100% working. According to various forum threads, it also seems that the FM tuner chip - although physically available on the PCB - can be disabled by a firmware update.
Version: YH-920 (REV 1.0) 2004.06.08
Version: YH-925 (REV 1.6) 2004.12.09 by Nichlas
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