Pentagram P6391

Router with 4 LAN + 1 WAN ethernet ports and WiFi based on Atheros AR2318.

On the right: second antenna.

HY57V641620: 8MB SDRAM, 3.3V.

Marvell 88E6060 - low power ethernet switch with 5 independent PHYs, 6 independent MACs, auto crossover, lookup memory for 1024 MAC addresses. Interestingly, each PHY supports technology called Virtual Circuit Tester,  according to datasheet able to locate cable problems (open/short cable) with 1 meter precision, based on Time Domain Reflectometry. Chip can be configured with MDIO interface or with external serial EEPROM.

Classic DC/DC converter with 34063 and some external transistor in SO-8 package. There is rectifying bridge on board, router is intended to be powered with AC voltage.

25L1605 SPI Flash memory, 2MB, 32 sectors 64kB each, 10k P/E cycles, 3.3V.

Planet WAP-1963A

Planet WAP-1963A is a wireless access point compliant with 802.11b (11Mbps max) WiFi. Since original firmware supports only WEP it is pretty obsolete today.

AP is based on RTL8181 SoC, integrating Lexra LX5280 32bit RISC CPU, 802.11b MAC, 2 ethernet MACs and PCI bridge. Since same SoC is used by more popular devices, e.g. Ovislink WL-1120AP there are some homebrew linux distributions able to run on it (http://sourceforge.net/projects/shortlinux/, http://rtl8181.sourceforge.net/). See also: http://www.linux-mips.org/wiki/Realtek_SOC.

RAM: 2 x IS42S16800A (128Mb Synchronous DRAM, 3.3V from ISSI)

Philips SA2400A transceiver, applicable also for ISM purposes.

IP101 Single Port 10/100 Fast Ethernet Transceiver with MII interface.

Macronix 29LV160ABTC-90 16Mbit FLASH, interestingly switchable between 8 and 16-bit modes. Operating at 3.3V.

9435A (FDS9435A) P-Channel MOSFET and AIC1578 DC/DC converter.

FX-350MS clone

 This very cheap (~$2.70) calculator was supposed to be my second/spare scientific calculator. Unfortunately it was disappointing in terms of both quality and function set.

This calculator is as generic as it could be. Under the sticker from local distributor there is just "Scientific Calculator" text, no brand name or anything like it anywhere (that may be a plus).

 Visually and functionally this looks like exact copy of Casio FX-350MS, although user manual was written poorly and quite incomplete.

 Device was dead on arrival with few of the LCD segments not working (exp part of the display).

 Another problem is very poor build quality, pressing buttons was causing severe distortions on LCD.

 My attempt to search for broken LCD connection and fix was proven unsuccessful as even careful manipulations were causing problems with other connections. Basically I believe that these connections are doomed to fail even on piece that is initially working. I have doubts if this thing passed DEKRA tests or these tests are worth a dime - when trying to search DEKRA seal database I couldn't get any result on ANY search term I've tried and this is supposed to be full-text search.

Another disappointment (same as with original Casio model) was lack of HEX mode considering it has advertised 240 functions.

WIWA HD95 i HD102 - porównanie

WIWA HD95 i HD102 to dwa bardzo podobne tunery DVB-T bazujące na układzie MSD7818.
Najistotniejszą różnicą jest rozmiar, brak zauważalnych różnic w firmware:

Tylny panel: inne złącza audio out, dodatkowy mechaniczny wyłącznik w HD102

 

Ze względu na problemy z działaniem (przerywanie) po ok. 1,5 roku użytkowania pilot z zestawu HD95 został rozebrany. Pilot posiada zatrzaski jedynie po bokach:

 

Porównanie działania pilotów wskazuje, że ten z zestawu HD102 posiada mikroprzełączniki jedynie przy przyciskach kierunkowych + OK, reszta oparta jest o gumki (co może być plusem). Z drugiej strony pilot z zestawu HD95 wydaje się wygodniejszy w użyciu (dużo lepiej układa się w dłoni) i ma subiektywnie lepiej dobrane funkcje (dodatkowa para P+/P- wygodniejsza w użyciu niż główny krzyżak).

 

AD009 jest popularnym układem przeznaczonym do pilotów uniwersalnych. Tu współpracuje z EEPROM 8kbit, ale podstawowe kody są prawdopodobnie zaszyte w pamięci OTP.

Nośna: 38 kHz.

Ciekawostką jest użycie nadawczej diody LED jako fodetektora, brak zewnętrznego rezonatora oraz tranzystora kluczującego LED.

Cienki laminat jest standardem, ale nie wróży długiego życia.

DT9205A multimeter review

DT9205A is extremely cheap digital multimeter. I've bought it for ~$7 plus shipping.
Specification looks fine. Few pages of instruction is shared with DT9201A, DT9202A, DT9203A, DT9204A, DT9206A, DT9207A and DT9206A. These other models differ mostly in function set selection, i.e. they offer frequency or temperature measurement in place of one of the 200MOhm resistance range. DT9203A and DT9204A have 4.5 digit reading and better nominal accuracy.

 Included probes are short (~60cm), made from cheap plastic (well, like anything else here) and very susceptible to damage - it feels like cable may tear out of plastic end at any moment.

Multimeter is based on ICL7106 chip (or its clone?). Two other ICs visible here are LM324. When looking at other disassembly pictures on the Internet it's clearly visible that actual PCB design varies greatly between particular multimeters marked as DT9205A. In particular many of them are built mostly with THT components placed on opposite side of the PCB. Schematic for those is easy to find and seems more or less matching this one - main difference is using 4 dual instead of 2 quad operational amplifiers.

 

Built quality and input protection is in pair with price.

 The lost art of using wire cutters:

 Input protection (MOV?) is almost touching transistor tester socket wires.

 Badly positioned LM324.

 Trace to nowhere (I doubt if this could be some kind of overvoltage protection; also I've already cut socket pins that were touching MOV here):

On a plus side: continuity tester has optical (LED) + acoustical signalization and indication works without any delay. Don't forget the price too.
Problems spotted:

• diode forward voltage measurement is highly inaccurate, i.e. it shows ~800mV forward voltage for red LED diode