My experience with repairing faults
2013-07-16 by Richard
Whilst answering a thread I thought it would be of use if I listed the problems I have come across in my travels, so here they are - only units I have had to repair.
SDS V
1)faulty PSU - transformers, regulators, Electrolytic capacitors and dry solder joints
2)module cards - bad connection to the buss board at the back (clean the contacts and re-seat the board. Lots of dry solder joints!!
SDS 7
1) PSU - see SDSV above
2) bad connections at rear buss board - see above
3) LOTS of dry solder joints throughout
4) operator buttons fail, spin encoder fails
5) Faulty Electrolytic caps
SDS 6
1) PSU - see above
2) Dry joints
3) Faulty Electrolytic caps
4) broken buttons
SDS 9
1)PSU - see above
2) Dry joints
3) Faulty Electrolytic caps
4) broken buttons
5) faulty CD4051 IC's in the multiplexor logic
Just about every PCB I have seen has had production rework carried out on it before leaving the factory. It must have been hard for Dave in those days. His business was expanding rapidly - this I think caused production/quality problems. Mind you I have seen the same quality issues coming from big names (Roland, yamaha, korg etc) from the same era.
SDS V
1)faulty PSU - transformers, regulators, Electrolytic capacitors and dry solder joints
2)module cards - bad connection to the buss board at the back (clean the contacts and re-seat the board. Lots of dry solder joints!!
SDS 7
1) PSU - see SDSV above
2) bad connections at rear buss board - see above
3) LOTS of dry solder joints throughout
4) operator buttons fail, spin encoder fails
5) Faulty Electrolytic caps
SDS 6
1) PSU - see above
2) Dry joints
3) Faulty Electrolytic caps
4) broken buttons
SDS 9
1)PSU - see above
2) Dry joints
3) Faulty Electrolytic caps
4) broken buttons
5) faulty CD4051 IC's in the multiplexor logic
Just about every PCB I have seen has had production rework carried out on it before leaving the factory. It must have been hard for Dave in those days. His business was expanding rapidly - this I think caused production/quality problems. Mind you I have seen the same quality issues coming from big names (Roland, yamaha, korg etc) from the same era.