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Voltage Drops from +15 to +12.59

Posted: Jul 3rd, '14, 02:31
by pascualfuentes
Hi, been building the 808 for about a week now and its been a blast. Every voltage testing was correct for each instrument, until I completed the Cymbal. When testing the positive voltage pin on U5 I read +12.59 V. The negative voltage pin reads out fine. Both positive and negative pins on U3 read out fine. I then checked U6 and U2 on the Cowbell, and both of those have also dropped to 13.89. These originally read out fine when I had first completed the Cowbell. I then followed the trace from positive pin of U2 up to R165 and took readings there. Before the R165 the readings are 14.88, but after the resistor I read a 12.59 again. I tried switching out the resistor with a 1/2 watt 100 ohm resistor and still the same. So I'm guessing there must be something in the Cymbal circuit that is putting a load on the voltage? Any ideas where else I can probe? Is this normal? Boy troubleshooting is fun!