Hi Ulf, I recently took my old TR707 out of the cupboard it had been sleeping in for about 15 years and switched it on. I bought it new in the 1980s btw.

I found that there is no sound from Low Tom or High Tom. The handclap and tambourine work but the volume is very low.

I found your page which gave me some hope! My knowledge of electronics is very limited however. That said, I am willing to have a go at fixing the machine. I wondered if two of the op amps might need replacing but I see that op amp IC202 (on page 8 of the service manual) is shared by both the Low Tom and Medium Tom. And IC203 is shared by the Hi Tom and Rim/Cow. If either of these op amps was faulty would we expect both sounds that share it to not work i.e. both Low Tom and Medium Tom not functioning and both High Tom and Rim/Cow? If so then I must conclude the op amps are not at fault here.

If you have any suggestions, I would be very grateful to hear them.

I tried running the test program by holding down CLEAR and INSTRUMENT when powering on but the machine did not enter test mode for some reason. Do you have any insight into this?

Thanks in anticipation

Martin