Got a nice Desk KW complete, appears all original, but hasn’t operated in over 20 years. Reportedly working ok when retired. Any suggestions on where to start, what to test and known pitfalls for Desk KW newbies? Any assistance greatly appreciated.
Mark
AF6IM
Well, this is certainly not a plug and play unit. It is 65 years old.
What prior experience do you have with HV electronic circuits and AM circuits in particular?
Don't assume:1) Any of the tubes are operational, have them tested or have good replacements available; even if the filaments light, it doesn't necessarily mean they are up to the task,
2) Prior owners have NOT made changes or revisions to any of the circuits,
3) cabling and wiring have good insulation,
4) relays are clean and transformers are functional,
5) Bleeder resistors are operational; always use a shorting stick.
See page 14 of this Brochure:
http://www.radiomanual.info/schemi/Surplus_Radioamateur/EF_Johnson_catalog_957.pdfThe Modulator may need an external audio Amplifier to drive it.
Phil - AC0OB