The problem:

I cannot enable recording in the right-channel using arecord.

I recorded using arecord -f dat -d 20 -D hw:0,0 test.wav.
Output in Left channel is fine. Output from right channel is 'Mic' (ie.
I record my typing and the playback of the recording through the speaker.
I have disabled Mic as a capture source so I do not know why this is happening.)

I initially thought there was a physical problem with the turntable.
But I get the same effect if I record from CD.

Hardware configuration:
-Turntable connected to amp (turntable plugged into 'phono' on amp)
-LineOut of computer connected to TapeIn of amp
-TapeOut of amp connected to LineIn of computer

Sound card installed on computer (cat /proc/asound/cards):
0 [nForce2 ]: NFORCE - NVidia nForce2
NVidia nForce2 with ALC650F at 0xe9080000, irq 16

Sound modules loaded (cat /proc/modules|grep snd)
snd_intel8x0 30620 3 - Live 0xf8c08000
snd_ac97_codec 95136 1 snd_intel8x0, Live 0xf9464000
snd_ac97_bus 2176 1 snd_ac97_codec, Live 0xf8bb3000
snd_pcm_oss 50848 0 - Live 0xf9493000
snd_mixer_oss 17920 2 snd_pcm_oss, Live 0xf90fc000
snd_pcm 84100 3 snd_intel8x0,snd_ac97_codec,snd_pcm_oss, Live 0xf947d000
snd_timer 22148 1 snd_pcm, Live 0xf8bf4000
snd 49124 10 snd_intel8x0,snd_ac97_codec,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer, Live 0xf910c000
soundcore 8160 2 snd, Live 0xf8bb5000
snd_page_alloc 8840 2 snd_intel8x0,snd_pcm, Live 0xf8bf0000

amixer settings:
Simple mixer control 'Master',0
Capabilities: pvolume pswitch pswitch-joined
Playback channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono:
Front Left: Playback 28 [90%] [on]
Front Right: Playback 28 [90%] [on]
Simple mixer control 'Master Mono',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 28 [90%] [off]
Simple mixer control '3D Control - Center',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 15
Mono: 13 [87%]
Simple mixer control '3D Control - Depth',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 15
Mono: 13 [87%]
Simple mixer control '3D Control - Switch',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'PCM',0
Capabilities: pvolume pswitch pswitch-joined
Playback channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono:
Front Left: Playback 25 [81%] [on]
Front Right: Playback 25 [81%] [on]
Simple mixer control 'Surround',0
Capabilities: pvolume pswitch
Playback channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono:
Front Left: Playback 26 [84%] [off]
Front Right: Playback 26 [84%] [off]
Simple mixer control 'Surround Down Mix',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Surround Jack Mode',0
Capabilities: enum
Items: 'Shared' 'Independent'
Item0: 'Independent'
Simple mixer control 'Center',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 26 [84%] [off]
Simple mixer control 'Center/LFE Down Mix',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'LFE',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 26 [84%] [on]
Simple mixer control 'Line',0
Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Front Left: Playback 26 [84%] [on] Capture [on]
Front Right: Playback 26 [84%] [on] Capture [on]
Simple mixer control 'CD',0
Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Front Left: Playback 26 [84%] [off] Capture [off]
Front Right: Playback 26 [84%] [off] Capture [off]
Simple mixer control 'Mic',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Mono
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono: Playback 26 [84%] [off]
Front Left: Capture [off]
Front Right: Capture [off]
Simple mixer control 'Mic Boost (+20dB)',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Mic Select',0
Capabilities: enum
Items: 'Mic1' 'Mic2'
Item0: 'Mic2'
Simple mixer control 'Video',0
Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Front Left: Playback 27 [87%] [off] Capture [off]
Front Right: Playback 27 [87%] [off] Capture [off]
Simple mixer control 'Phone',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Mono
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono: Playback 27 [87%] [off]
Front Left: Capture [off]
Front Right: Capture [off]
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined cswitch cswitch-joined
Playback channels: Mono
Capture channels: Mono
Mono: Playback [off] Capture [off]
Simple mixer control 'IEC958 Playback AC97-SPSA',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 3
Mono: 0 [0%]
Simple mixer control 'PC Speaker',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 15
Mono: Playback 0 [0%] [off]
Simple mixer control 'Aux',0
Capabilities: pvolume pswitch pswitch-joined cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: Playback 0 - 31
Front Left: Playback 31 [100%] [off] Capture [off]
Front Right: Playback 31 [100%] [off] Capture [off]
Simple mixer control 'Mono Output Select',0
Capabilities: enum
Items: 'Mix' 'Mic'
Item0: 'Mix'
Simple mixer control 'Capture',0
Capabilities: cvolume cswitch cswitch-joined
Capture channels: Front Left - Front Right
Limits: Capture 0 - 15
Front Left: Capture 14 [93%] [on]
Front Right: Capture 14 [93%] [on]
Simple mixer control 'Mix',0
Capabilities: cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Capture channels: Front Left - Front Right
Front Left: Capture [off]
Front Right: Capture [off]
Simple mixer control 'Mix Mono',0
Capabilities: cswitch cswitch-joined cswitch-exclusive
Capture exclusive group: 0
Capture channels: Front Left - Front Right
Front Left: Capture [off]
Front Right: Capture [off]
Simple mixer control 'Analog to IEC958 Output',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Channel Mode',0
Capabilities: enum
Items: '2ch' '4ch' '6ch'
Item0: '2ch'
Simple mixer control 'Duplicate Front',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Exchange Center/LFE',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'External Amplifier',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Swap Surround Slot',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]

Any help appreciated. I'm stumped.
--Charlie

not meaning to state the obvious but make sure mic is not pluged into right line in.

I don't mind the obvious. Most solutions are when you find them. I have checked that line-in cable is plugged into line-in and that microphone is plugged into Mic. So I can rule out Mic ---> LineIn (R). Thanks for your help.
Regards,
--Charlie

I have just found that selecting 'Mic' as the capture source produces a correct recording (ie. both left and right channels are recorded ok). So the source of the problem appears to be some difference between 'LineIn' and 'CD' as the capture source and 'Mic as the capture source.