bullerp Posted June 10, 2017 Share Posted June 10, 2017 My Spider iv 150 died with a pop and a puff of smoke. I found that D1 on the power supply board had disintegrated. I replaced it copying the polarity of D2 but that diode failed immediately. Now with a new diode reversed when switched on all front panel leds light up but after 10 seconds they go out one by one. This occurs with or without the power amp board connected. What is the correct polarity for D1? A sketch would be helpful. Any ideas on the cause of the initial failure would be appreciated. Thanks. Quote Link to comment Share on other sites More sharing options...
markhenesian Posted July 3, 2017 Share Posted July 3, 2017 I found the schematic at It's going to take some digging to find the diodes. Might have to take the head to a amp repair place, sounds like more is wrong than just the diodes, Mark Quote Link to comment Share on other sites More sharing options...
markhenesian Posted July 3, 2017 Share Posted July 3, 2017 The link to the Spider IV schematic is in the third post from the top, The detailed power supply/board schematic does not appear to be included in the SPIDER IV drawing, however the D1-D4 diodes are listed as SMALL SIGNAL AXIAL TH 1N4002 types. You might look at the SPIDER III schematic (download same link). It looks like a more complete drawing, Mark Quote Link to comment Share on other sites More sharing options...
bullerp Posted July 7, 2017 Author Share Posted July 7, 2017 Thanks Mark. I think the power supply is ok. The voltages around the voltage regulators on the preamp/effects board are what they should be. I guess something on that board caused D1 to toast. Repair is likely to cost more than a SH amp head. I may give up and put it on Ebay as not working. Quote Link to comment Share on other sites More sharing options...
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