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| Identify giant transformer from 1978 tape reel |
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| Jwillis:
--- Quote from: mikerj on May 03, 2019, 09:22:09 am --- --- Quote from: Jwillis on May 02, 2019, 08:12:51 pm ---The biggest problem with using a lamp to find how a transformer is configured is that the light draws current and some winding s on the transformer may not handle that current and could potentially burn up the winding s . The safest way is to use low voltage AC instead and measure with a multimeter . --- End quote --- The point of using a lamp is to wire it in series to limit the current, not to draw current. --- End quote --- A 100w incandescent light bulb has around 140 ohms resistance with a hot filament . At 120V will draw 0.85 amps which is more than enough to exceed the current rating wire 22 AWG and higher .A 40W bulb has a hot resistance of around 360 Ohms which gives around 0.3 amps which is enough to exceed the current rating of 34 AWG and higher. If a lamp is used , keep the test duration's short . Using a lower voltage is just an alternate method of determining the properties of an unknown transformer without concern of damaging anything or handling high AC voltage. |
| Richard Crowley:
One of the most basic exercises in exploring a mystery transformer is to create a grid to record resistance measurements between each wire and every other wire. Then you will see how many windings, whether they are tapped, and their relative resistance compared to each other. Without something like that to start from, you are wandering around in total darkness. |
| queennikki1972:
Model was Pioneer RT707 if anyone can find a schematic with the transformer on it.. I wouldnt even begin to know where to look. transformer is RTT-118 |
| Richard Crowley:
The very first hit on Google yields the first-class service manual PDF download: https://www.esotericsound.com/SalesImages/rt-707sm.pdf And if you look in the lower right corner of page 61, will see the transformer with all the wire colors identified. Google is your friend. |
| MarkF:
Close. Hers has two extra wires (purple and black). Maybe two primaries for 120V or 240V operation? pg.59 says power transformer part no. RTT-115 |
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