Heathkit SB-220 Linear Amplifier:Complete Restoration Guide Circuits • Cabinet • Safety • Component Replacement • Modern Upgrades 📝 VK6ADA Technical Papers 📅 March 2026 ⚡ 2 kW Class — 3-500Z Triode ⚠ High Voltage Equipment Abstract. The Heathkit SB-220 is…
Community Join the Vintage AmateurRadio Restoration Group A dedicated mailing list for amateurs who restore, study, and operate vintage HF equipment — Collins, National, Hammarlund, Hallicrafters, Drake, Heathkit, and beyond. Technical advice, restoration notes, and a community that values doing…
VK6ADA vk6ada.com.au • r-390a.net Collins S-Line — Engineering Design Document Collins 180S-1Jumper Plug Reproduction A comprehensive engineering design for fabricating reproduction jumper plugs for the Collins 180S-1 antenna tuner — including circuit analysis, RF electrical requirements, dimensional specification, parts list,…
VK6ADA vk6ada.com.au • r-390a.net Collins S-Line Accessories Restoration Series Collins 180S-1Antenna Tuner Restoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins 180S-1 pi-network antenna tuner — covering front panel and cabinet finishing, vacuum variable…
VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-390/URR ReceiverRestoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins R-390/URR military HF communications receiver — covering disassembly, the critical green gearwheel procedure, cabinet refinishing,…
VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-390A/URR ReceiverRestoration Guide A complete field guide to the cosmetic restoration of the R-390A/URR military HF communications receiver — covering disassembly, haze gray finish specification, panel marking restoration, hardware treatment, manufacturer…
VK6ADA vk6ada.com.au • r-390a.net Boatanchor Receiver Restoration Series Hammarlund SP-600Restoration Guide A complete field guide to the cosmetic and mechanical restoration of the Hammarlund SP-600 series military HF communications receiver — covering variant identification, the Black Beauty capacitor problem, front…
VK6ADA vk6ada.com.au • r-390a.net Collins Military Receiver Restoration Series R-388/URR ReceiverRestoration Guide A complete field guide to the cosmetic and mechanical restoration of the Collins R-388/URR military HF communications receiver — covering disassembly, paint stripping, cabinet refinishing, panel marking restoration,…
VK6ADA vk6ada.com.au • r-390a.net Collins S-Line Restoration Series Cabinet, Bezel & Trim Restorationfor the Collins S-Line A complete field guide to restoring Collins S-Line cabinets, front-panel bezels, and all associated trim hardware to factory appearance — covering disassembly, chemical stripping,…
If you own or are restoring a Hammarlund SP-600, one resource you need to know about is Perry Sandeen’s An Anthology of Technical References for the Hammarlund SP-600 and its Variants. This is a comprehensive compilation covering the SP-600 receiver family…