After putting off working on my HF-2500 for far too long, I actually found the time to get some serious work done on the amp. Over the years, time and heat has taken its toll on it and although it still worked [just] – it was in a bit of a mess and required a good strip down and refurbishment. Here’s what the issues are and what’s planned.
- Power Supply: After 20 years, the electrolytic capacitors are guaranteed to be poor.
- Power Supply Board: Plate meter fails to read. An open 1Meg resistor on the PSU board.
- Power Supply Board: Schematic shows a 150k 2w resistor. The fitted one is 10k.
- Power Supply Board: Plate meter fails to read. An open 200ohm resistor on the PSU board.
- Rotary Band Switch: [Switches the low power relays] – poor operation/bad contacts/worn.
- Rotary Band Switch: Fails to operate on 10m. Broken/Bent stopper pin.
- Main QRO Band Switch: Shaft coupler spins. Poor quality only held by 1 screw each end.
- Main QRO Band Switch: Spring is too tight. You need two hands to rotate the switch.
- Main QRO Band Switch: Small nylon locating roller pin broken.
- RX/TX Relay: On receive the signal often drops by 6-12db. Probably a poor/worn contact.
- Front Panel Wires: All soldered. Replace with a 6 way PCB mounted terminal block.
- Front Panel Band Switch Knob: Broken in half.
See the Part 1 – Introduction Video Here
Click on any of the images below for a larger hi-res version.
