EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: scrubba on February 18, 2020, 04:20:39 am
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I am a newbie both to this forum and the electronics world. I need help in converting a Leader LAG-120B audio generator from 220v to 110v. I've consulted Leader, and they have not been able to help me thus far. They sent me a schematic of the power transformer for the LAG-120A which has a different primary tap configuration. It shows 4 taps and a series to parallel conversion. The LAG-120B transformer has 3 taps on the primary. Any helpful information would be appreciated. Thanks.
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The manual is here: http://bama.edebris.com/manuals/leader/lag120b (http://bama.edebris.com/manuals/leader/lag120b)
If that doesn't match your unit, post a photo of the transformer wiring.
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Thank you edavid.
The schematic matches my unit, but I am still unsure of which wires to re-route for 120v. Manual states voltage is adjustable from 100v, 120v, 220v, and 240v.
I'm not sure, but I think the schematic from the manual shows wiring for 100v.
Also attached is a photo of the transformer as presently wired. The person I bought the unit from said it is wired for 220v.
Many thanks for your help.
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Looking at it, this is what I would assume the connections to be.
(Assuming between #1 and #2 is 100v winding and between #2 and #3 is 15v winding.)
I'd expect that the schematic shows 100V connection.
If you move the wires from the #2 termimals directly to their respective #3 terminals, you'll get 115V.
Connect line to right #1, then right #2 to left #1, and left #2 to neutral and you have 200V
Connect line to right #1, then right #3 to left #1, and left #2 to neutral and you have 220V
Connect line to right #1, then right #3 to left #1, and left #3 to neutral and you have 240V
Best to check on a variac to work out the ratios in each connection though.
Or you could just disconnect J6, stick a multimeter in and feed in a low voltage from another transformer with alligator clips for easy connection and a light globe for current limiting, say 12v or 24v, then multiply it out to find the correct combination.
Ie, for the correct combination for 120V in, at 12v input, you should get about 2.6V out, for 24V input, 5.2V or thereabouts.