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.