Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Jacques Are you sure you are looking at an S-85?? I see no indication of cores in the RF tuning ?for bands 1,2 ?. Note Bands go 1,2,3,4? up in frequency, but coil numbers go the other way.. gets us all!? ? Re ???Is it just me, or the two lower band inductors are connected in reverse (one for each other) in the S85 schematic ??? Do you mean L3? which serves both bands ? ?IF so we have gone on wild trips about that. I finally drew the switch wafer in all positions, It is somewhere. It is too hard to spell it out, without a picture /g/HallicraftersRadios/message/31639?? ?I drew this just to find out the ground switch stuff while the you need to keep the coils in hand 2. I could not rotate this switch in my head. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jacques_VE2JFE via groups.io
Sent: Sunday, February 16, 2025 4:57 PM To: [email protected] Subject: Re: [HallicraftersRadios] S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak! Importance: High ? Emanuele, Fantastic pictures, but I do not believe that the C7A tuning cap can be at fault. Obviously the coil have too much inductance, so it’s core have to be moved OUT of the coil (to the top, or to the bottom, I do not know which one will be best). Normally, the trimmer cap should be set at it’s center setting, then the core of the coil have to be adjusted to obtain a peak at the low frequency specified in the alignment instructions, then the response should be peaked with the trimmer at the high frequency specified in the alignment instructions. Then go back to the low frequency with the core, then to the high frequency with the trimmer, and doing this several times until no improvement is measured. ? But Ah… I understand: no alignment instructions in the manual for the CORES of the coils, like if nobody had touched those since the day of the manufacture !!! AARGH ! ? Find a plastic driver and MOVE those cores while observing what happen with your Spectrum Analyser, PLEASE ! BC band: low side at 600kHz (L3 core ??), High side at 1400 kHz (C4 trimmer), then loop again. ? Is it just me, or the two lower band inductors are connected in reverse (one for each other) in the S85 schematic ??? ? ? ? 73, Jacques, VE2JFE in Montreal ? -- don??? va3drl |
don Root