Band Switch Notes, Late Radios

All of this is for the SX-28A. The late radios have completely redesigned modules. They're more like modern plug-in asseblies but without connectors.

For all of the following links, assume:

• The radio is upside down.
• The view is from the front panel side.
• "Up" means twards the ceiling, not the top of the radio. "Down" is the opposite.
• "Front" means twards the front of the radio and the viewer, "back" means away.
• Sometimes a single wafer will contain two switches - one on the front side, one on the back.
• There are 10 wafers numbered from the rear of the radio to the front.
1. Inside 1st RF - SW8-1
2. Inside 1st RF - SW8-2
3. Inside 1st RF - SW8-3 and SW8-4
4. Inside 2nd RF - SW8-5
5. Inside 2nd RF - SW8-6 and SW8-7
6. Inside mixer - SW8-8
7. Inside mixer - SW8-9 and SW8-10
8. Inside osc - SW8-11
9. Inside osc - SW8-12 and SW8-13
10. The wafer on the outside of the osc module - SW8-14 and SW8-15
• Some of the wafers are identical to ones in other modules. I treat them as different. This is good to know if you need wafer X but it's not available but wafer Y is and X and Y are identical.
• For the most part, the wafers in the early radios are the same as in the late but there are a few differences.
• There is a page to help you understand orientation here.

Read about 1st RF switches.

Read about 2nd RF switches.

Read about mixer switches.

Read about osc switches.

Page: /Band_switch/Late/Late_band_switch.shtml

Last modified: Monday, 1 Jun 2026