FS#1075 - xiaomi mini hardware/power issues #6645
Comments
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psyborg55: mtk driver used from PandoraBox-ralink-mt7620-xiaomi-mini-2017-01-03-git-6c24a7a-squashfs-sysupgrade voltage measured on LNA0 3V, on LNA1 2.2V maybe the primary amp is overloaded |
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psyborg55: of course that was first measuring. another attempts gave 0V on both amps on the pins 1-2 measured first time! which makes no sense and is completely retarded regardless if powered from wall or battery. another pin measurement 1-3 also show lower voltage on LNA1 about 1.84V while LNA0 is 2.25V (LNA pinout can be found in http://www.mouser.com/ds/2/196/bf776-90370.pdf) so i took multimeter just to find out C558 between switch and amp had 0 ohm resistance while same capacitor on chain0 had some resistance, of course unsoldered it and tried to short pads which completely confused dumb mediatek chip that showed 20dB less rssi so i soldered the thing back and the chip is stuck calculating rssi from chain0 only - my 2T2R test has now same values as other 3 tests. there was no performance drop, but that should still be verified using mtk driver. |
psyborg55:
i've noticed recently there is a signal drop on mini when used legacy wifi mode. this mode disables chain1 in mtk driver and use only chain0. i've made detailed test of both firmware with 3 different cards. can somebody else try the same test to conclude if it is power configuration issue or hardware damage?
TX values are card TX which means RSSI from router while RX values are mini's txpower levels received by cards.
AR9271 is AWUS036NHA with 10dB comfast antenna
RT5370 is EDUP 150N mini usb adapter
AR9462 is minipci card
NC means card did not detect beacons in this mode
TX/RX path configuration was changed within eeprom offset 0x34
test results:
MTK 2T1R OpenWrtG N20 N40 G N20 N40
-25 -25 -25 AR9271 TX -47 -47 -47
-61 -48 -48 AR9271 RX -52 -52 -52
NC -25 -25 RT5370 TX -50 -50 -50
NC -29 -29 RT5370 RX -33 -33 -37
-25 -25 -25 AR9462 TX -41 -45 -45
-40 -25 -25 AR9462 RX -35 -35 -35
MTK 1T2R OpenWrt
G N20 N40 G N20 N40
-78 -78 -78 AR9271 TX -47 -47 -47
-70 -70 -70 AR9271 RX -75 -75 -75
-79 -79 -79 RT5370 TX -50 -50 -50
-59 -59 -59 RT5370 RX -59 -59 -59
-78 -78 -78 AR9462 TX -43 -45 -45
-45 -45 -45 AR9462 RX -50 -50 -50
MTK 1T1R OpenWrt
G N20 N40 G N20 N40
-25 -25 -25 AR9271 TX -47 -47 -47
-70 -70 -70 AR9271 RX -75 -75 -75
-25 -25 -25 RT5370 TX -50 -50 -50
-59 -59 -59 RT5370 RX -59 -59 -59
-23 -23 -23 AR9462 TX -43 -45 -45
-45 -45 -45 AR9462 RX -50 -50 -50
MTK 2T2R OpenWrt
G N20 N40 G N20 N40
-46 -46 -46 AR9271 TX -37 -37 -37
-70 -48 -48 AR9271 RX -52 -52 -52
-44 -44 -47 RT5370 TX -33 -33 -39
-59 -29 -29 RT5370 RX -35 -33 -37
-40 -45 -47 AR9462 TX -35 -37 -39-45 -25 -25 AR9462 RX -35 -35 -35
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