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SE-5a Turret board assembly

Your SE-5a kit contains a turret board, already staked with turrets for you to add and solder your kit's board-based components. Click here to open a page with detailed photos of the layout of the components on this board.
      The top picture shows the components soldered in position. The bottom photo is annotated with component numbers (C1, R4, etc). Use that as your guide to component layout.

Resistor notes

Make sure to use the larger resistors - which are rated at 1W or 2W - in the appropriate position. For example, there are four 100k resistors, one of which is substantially thicker than the other three. The smaller ones are R2, R5 and R7 in the preamp (below left), and the larger one is R14, with a higher power rating because it connects directly across the high voltage supply (below right).

Polarity notes

Seven of the capacitors have a polarity that you need to follow:
* C1 negative towards bottom edge
* C3 negative towards bottom edge
* C7 negative towards bottom edge
* C8 negative towards bottom edge
* C9 negative towards bottom edge
* C10 negative towards bottom edge
* C11 negative towards bottom edge
      In addition, the diodes (D1 and D2) must also be inserted the correct way around. Follow the example shown in the component layout diagram, paying close attention to the orientation of the grey-silver bands at one end of each diode.

Side-mounted components

Most of the components are best mounted using the holes in the top of the turrets. However, it's best to side mount some to make it easier to connect wires when you get to the chassis wiring. The components I suggest you side mount are: D1, D2, R11, R12 (shown below).

Ground and other connections

Once all of the components are in place on the turret board, use some of your kit's uninsulated solid-core wire to make several connections along turrets on the board - as shown in the picture on the right.
      First, solder two ground bus wires: the first to connect turrets A-D, and the second to connect turrets E-J. These wires will connect all of these components to ground once the wiring is complete. Next, connect the two turrets K-L near the top of the board. Finally, connect the two turrets M and N along the top of the board. Now you're ready to add the wiring.
      Note: There will be a resistor left over - R1. This is normal; put it to one side for the moment.

Turret board soldering tips
* Do a 'dry run' before you start to solder. Line up all of the components in their correct order, from left to right. This helps you to avoid mistakes and having to desolder components.
* Even if you can read resistor colour codes easily, use your multimeter to check the resistance value, just in case.
* Check twice and cut once - extending a component lead that you've mistakenly trimmed too short is a pain, so double-check that you've got the correct component before cutting the lead.
* Aim for solder joints that are shiny and gently domed. Solder should 'flow' around the component leads and turret surface - almost seamlessly.
* If a solder joint looks 'lumpy' or dull, you may have a poor joint, which can cause the amp not to work (or even to work intermittently - a tricky problem to debug). If in doubt, resolder the joint.
* If the turret's top hole is crowded, with no room to fit another lead, don't worry - use the side of the turret. There are side-ridges for this purpose - wrap the new lead around the turret's side and solder it in position.

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