Time-Nuts: I partially fixed an FTS1050A by replacing a bad +-15V regulator module. Before the replacement, the unit could not be adjusted on frequency. After replacement the oscillator is on frequeny mid-range of the digital adjustment pot. I thought it was fixed but.... However, the ADEV is horrible, around 1E-7 over wide ranges of time scale. I note that the 22V going to the RF buffers is unsteady, going up and down around 0.25V every few seconds. Maybe there is a correlation? I haven't found schematics for the FTS1050A in any of its many variations. I have noticed on this and other FTS1050A units that the 22V goes up to around 30V for a minute or so when the unit is first powered up. Is this an attempt to improve oscillator warm-up? In any case that seems to work o.k. Once warmed up, the 22V line remains erratic indefinitely on this particular unit. I am guessing a bad electrolytic somewhere. a marginal 22V regulator transistor on the back panel, or maybe something wrong with the oscillator heater. Any thoughts? Thanks- Jim

Jim if its like the 4050 there is a 22 to 32V inverter in one of the modules the electrolytic may be bad there. Mine were blown and leaking. Ate various traces. The ones in my unit were silver bearing with red band. If that band turns black change ASAP. Paul WB8TSL On Sat, Oct 19, 2024 at 3:20 PM AC0XU (Jim) via time-nuts < time-nuts@lists.febo.com> wrote: > Time-Nuts: > > I partially fixed an FTS1050A by replacing a bad +-15V regulator module. > Before the replacement, the unit could not be adjusted on frequency. After > replacement the oscillator is on frequeny mid-range of the digital > adjustment pot. I thought it was fixed but.... > > However, the ADEV is horrible, around 1E-7 over wide ranges of time scale. > I note that the 22V going to the RF buffers is unsteady, going up and down > around 0.25V every few seconds. Maybe there is a correlation? > > I haven't found schematics for the FTS1050A in any of its many variations. > I have noticed on this and other FTS1050A units that the 22V goes up to > around 30V for a minute or so when the unit is first powered up. Is this an > attempt to improve oscillator warm-up? In any case that seems to work o.k. > > Once warmed up, the 22V line remains erratic indefinitely on this > particular unit. I am guessing a bad electrolytic somewhere. a marginal 22V > regulator transistor on the back panel, or maybe something wrong with the > oscillator heater. Any thoughts? > > Thanks- > Jim > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com >