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In Reply to: RE: Conrad Johnson PV5 conversion from 110v to 220v posted by lorcoll on June 28, 2008 at 10:58:11
Hello Lorenzo,I am not a technician, but I will try to assist you. You need a variac and a soldering iron, perhaps some clip leads, and a DMM.
1) With the unit fully on, and your step up trannie in place as usual, carefully measure your line voltages, and ALL major AC voltages on both sides of the power transformer. Also record your DC voltages, after the unit's B+ filtering. Carefully write this all down.
2) These are your "reference voltages" which you will seek to replicate at the end of this process.
3) Variac up the unit with the step up trannie being used, some small standard percentage, say 33%, and determine voltages, either VAC or VDC, at ALL the same locations as you checked as your "reference voltages", in step 1) above. Take careful written notes!!
4) Power unit down, disconnect AC plug from the wall!!
5) You should use an ohmmeter, DMM on lowest ohms scale, to measure all of the primary's taps and get an idea of what you have. DRAW out the wiring, carefully taking notes, before disconnecting anything !! You will have to DISCONNECT some of the primary wires, so as to eliminate the paralleling and to separate the two 120 VAC windings. Find two sets of three wires that have continuity with your DMM, as these are associated with each of three two primary windings. The highest DCR reading on each winding are the leads associated with the FULL winding.
Series connect the two primary winding wires experimentally, maybe with clip leads, .... Slagle has 'em. :-) If your newly reconnected DCR reads twice of what one unparalleled winding reads, you have a 50% chance at early success.
Plug unit into the variac and the wall directly, (no longer using step up trannie). Variac power up to 33% a second time, HOPE to get all SECONDARY and B+ voltages looking logical ( same as in step 3) ) at 33% on the variac.
If you do not get equal voltages, experimentally clip lead the two primaries so as to get the "correct" SECONDARY and B+ voltage readings at 33%. ie: You want the windings connected in series addition, not in series buck /subtraction.
6) Continue to variac up the unit, testing it at 50%, to see if the voltage tracks with the voltages you expect. Do the same at 80% line, write this down. Then, check at 100% of line. Write this down - so you know the voltages match the original test results, as in 1), the "reference voltages", and you have succeeded.
6) Disconnect unit from wall and carefully / neatly solder all wires, eliminating the temporary clip leads.
Dave Slagle, I was just funning you about clip leads. You're the man !!
Jeff Medwin
Edits: 06/28/08Follow Ups:
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