The C channel showing the output from.Búsquedas XXX más relevantes nsfw korea honey moon aka korearose aka aka asuka hika Belinda aka Bely molly aka regina Jason K aka Dongzilla Aka daniels Tiny Teen aka Lady Jay aka Lady Jay aka hika eva-veil-aka-yeeesye-1. Funnily enough, I’ve decided to quit because it didn’t leave me enough time for cosplaying. ‘Due to her, I’ve found my vocation, my loving and supportive boyfriend and even my previous job of a video game club administrator. This is really the only bit of the counter which actually operates at 3GHz - everything else uses the beat frequencies that this generates, although the local oscillator pulse chains do need sharp edges as we're relying on their harmonic content. ‘Actually, being Lara is a very serious part of my life’, Tanya proceeds. The two sampling mixers, note the interesting surface mount construction. This is then doubled to give an overall division of 200 and fed to the rest of the counter. It uses two sampling mixers together with two local VCOs running in the range 19-21MHz - one tracks the input frequency (such that one harmonic of the local oscillator corresponds exactly with the input frequency), one tracks at a frequency 399/400ths of the first such that when this is fed to the second sampling mixer a beat frequency is generated which is 1/400th of the input.
I'm rather glad that this section appears intact because I didn't fancy delving in to fault find. It has a single 74LS390 dual decade counter rather than two 74LS90's The next two photos show the 3GHz prescaler. So I now have a working 9921 and a dead 9917 (well, channel B is probably OK) - given the fact that the 9921 is the better counter that's much better than a dead 9921 and a not-working-enough-to-be-useful 9917. The 9917 didn't really survive the removal of the SP8635B - despite being careful the tracks seemed to be glued to the PCB with wallpaper paste and I lifted a couple of pads and tracks.
Channel B was still out but that turned out to be the fact that I had cracked a small resistor next to the ECL chip - as that fed the signal into the 'low level inhibit' circuit it basically behaved as though no signal was applied. Transferred the IC to the 9921 and bingo, check mode now showing 1MHz (well, 1MHz plus one count which is often the case with the 99xx series) and channels A+C were working - at least as much as a brief test could tell. I haven't yet found time to look at it to discover why so it was an ideal candidate for a donor. Fortunately I did have a spare in a 9917 which counts erratically.
0 kommentar(er)
