On my ID L the sound just stoped working, I opened it and found out that one wire detached from the speaker.
The main problem of most tamas is the soldering is very delicate and wires are so fragile and short so they can come off by themselves over the time. So you can, - or ask someone, - to...
I had the same problem with couple of my old Tamas, in both cases the problem was in failed capacitor. Ask someone who can solder to replace the capacitor (10uF/16Volts), it's very easy job, takes around 5 minutes to do it.
As to the V6 - it's pretty needy compared to V4, V5, these ones you can...