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Title: 1st Time Power up DC30 Post by: XB9R on July 13, 2011, 09:57:44 AM Hoping someone can shed some light on something I'm seeing with a first time power up of a DC30 through a Light Bulb Limiter. Have been over the schematic / layout numerous times have done continuity checks all over the amp and all looks good. When using the limiter with a 25watt bulb, Limiter plugged into mains, Amp plugged into limiter, standby switch in "Standby" and flip the power switch to the "On" position No tubes installed. The 25 watt bulb glows very faintly. repeated the process using a 40, 60, 75 & 100 watt bulb and none of them glowed at all, which is the result I was after. If the 25 watt bulb is passing the least amount of power to the amp is it this resistance that it is generating purely causing the bulb to glow?
from the above test, with the 60watt bulb in I am seeing the follow voltages, input 230v, seeing 225v at the IEC plug, mains fuse, on off switch as expected. PT secondaries are showing 275v at pins 5 & 7 of the rectifiers & 6.06v at the heaters (within expected values), so to me so far so good. any ideas? Title: Re: 1st Time Power up DC30 Post by: XB9R on March 15, 2012, 07:22:59 AM Just thought I should update this post, in case anyone else wanted to use this method of first time power up, since my build went off with out a hitch. USE THE 60Watt Bulb!!!! everything turned out fine, trust your multi-meter and if you have done the basic continuity checks and your voltages check out and are within expected ranges you should be good to go with installing your tubes and rechecking your next range of voltages.
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