Page 4 of 7
If you plan to use SOIC opamps you may start soldering them because if you not have a small soldering iron it may be hard to do it later. If you have a normal iron with a small tip it's not that hard to solder those IC's later.
- 0805 snubber resistors, 1 ohms or 0.5 ohms, two 1 ohms on top of each other. You can also put a tin drop or a wire there if you don't want this snubber.
- Wire jumper at B1 for 230 volts and B2, B3 for 115 volts. Place the jumper or jumpers on the solderside, otherwise hard to change if necessary. Cut the wires in the componentside which are under the transformer.
- All small low parts like resistors, zeners. Notice: zener OR LED, see the text above. Notice also the polarity of those parts.
- Plastic caps
- Small signal transistors, reference IC's
- Rectifier bridges, or discrete power diodes
- Big electrolytic caps
- Fuse holder with insulation cover, see picture
- Heatsinks with regulators and power transistors. The heatsinks are grounded but none of the parts have their cases connected to ground. Therefore they must be insulated with a washer and bush. The washer may be made of Kapton (orange plastic), silicone rubber or mica. If silicone rubber is used there is no need for heat compound (white messy grease, increases the heat transfer). You don't need any grease either for mica or Kapton washers if the power dissipation is low, like 2-3 watts. In case of you'll use heat compound, apply a THIN layer on both sides of the washer. A thick layer grease will create a huge sticky mess, avoid it. Mount the parts first on the heatsink, then solder the parts and also the heatsink but it may be a good idea to solder the heatsink with only a small drop of tin, only to keep it in place. If you of some reason want to remove it it's easier if it isn't so thoroughly soldered.