How to fix your 260Z or 280Z clock.

Transcription

1 Sujt Fixing th Kanto Siki lok Author E. Bttio How to fix your 260Z or 280Z lok. I first wrot this up aout two yars ago. This is th sond vrsion of this produr. It is not vry muh diffrnt to my first ffort xpt it orrts on (major) mistak. I had th diagram with th transistor pin assignmnts wrong. I had two of th transistors mixd up. That is now fixd. I hav trid to fix th arlist loks with th motor drivs ut had no suss. Ths had Jo stampd on th lok fa and wr found on th 240Zs. If you hav on of ths, this doumnt won t hlp you. I hav also trid fixing my 260Z lok (and th loks out of som othr 260Zs). Ths had an ltroni ard rathr than a motor insid that drov th lok movmnt. Thy had Kanto Siki printd on th lok fa (though partly osurd y th zl). I xpt that th 280Zs also usd th sam lok (w did not s th 280Z in Australia). Chris A also tlls m th Citizn lok works th sam way. If you hav any of ths loks, and a littl it of ltronis know-how (or a frind with som ltronis know-how), thn hopfully this an hlp you fix your old lok. 1. Clok rmoval. Rmov th lok from th ar (you may hav to do this through th glov ox), and thn rmov th lok from th housing. You will hav to pull th als through thir ntran point at th rar of th housing. On you xtrat th lok som of th way, not whr th lu and lak als go and d-soldr thm. Pag 1 of 5

2 Sujt Fixing th Kanto Siki lok Author E. Bttio 2. Visual insption. Dos vrything look ok? Any urnt-out or rokn omponnts? Any rokn gar tth? (Thr hasn t n anything visually wrong with th loks I hav dalt with yt.) 3. Ciruit oard rmoval. Rmov th iruit oard. It is hld in pla y two srws. B arful whn you rmov it aus th ojt that looks lik a oppr disk is atually and mass of tightly wound, vry fin namlld wir. B arful not to damag it. 4. Capaitors. Thr ar thr ltrolyti apaitors on th oard. Ths ar ovr thirty yars old now and wr th first things I rplad. I tstd thm all whn I rmovd thm and found that on had gon opn iruit on two of th thr loks I fixd. I rplad thm all. I rplad two of thm on ah lok with quivalnt ltrolyti apaitors, th third smallr on (220nF) I rplad with a polystr apaitor (I hav mor onfidn in polystr apaitors). As th ltrolytis ar polarisd, not th orintation of th ons you rmov (whih sid has th minus sign markd on it), and nsur th nw apaitor gos in th sam way. A polystr apaitor is not polarisd and an go in ithr way. Pag 2 of 5

3 Sujt Fixing th Kanto Siki lok Author E. Bttio 5. Ciruit analysis. Aftr rplaing th apaitors, my first lok workd for a whil, thn slowd, thn stoppd. My sond lok still didn t work, and my third lok workd. It was tim to onsult th iruit diagram of whih thr was non (that I ould find). I trad it out and what I am up with is shown low. Th dottd ox rprsnts th disk-lik ojt. I ould s four tiny wirs oming from it, and it sms as if it is two windings in th on omponnt. Aftr analysing th iruit around it, I am to th onlusion it was som sort of pik-up +12V 680R Pik-up 22uF 5V1 2M 10uF 850R 220nF 0V C828 E. Bttio 2006 How it works: Th 680R rsistor, th 22uF apaitor (in on lok it was 10uF) and th 5.1V znr diod togthr provid a smoothd 5V supply for th rst of th iruit. Th 2M rsistor provids th ias for th transistor so that it is almost turning on. Th first winding in th disk-lik ojt (lts all it a pik-up ) dtts th magnts on th osillating pndulum as thy swp past. As thy swp past, thy gnrat a small ltrial puls in th first pik-up winding. This puls passs through th 10uF apaitor into th as of th transistor, rifly turning it on. Whn th transistor turns on, urrnt flows through th sond pik-up winding and th 850R rsistor. This short urst of urrnt through th winding rats a small magnti puls that givs th magnts a small nudg whn thy pass to kp thm going. It s a it lik sitting at th ottom of a playground swing and vry tim you s it swing past you, you giv it a littl push to kp it going. Board layout - Viw from undrnath Pag 3 of 5

4 Sujt Fixing th Kanto Siki lok Author E. Bttio 6. Tsting. As I said aov, on I rplad th apaitors on th first lok, it workd for a whil thn it slowd (th osillating pndulum was still roking ak and forth, ut not nough). Evntually it stoppd. I had a look at th voltag at th transistor olltor (ottom of th 850R rsistor) for it stoppd. Th voltag wavform lookd lik this: Th olltor voltag drops to only aout thr volts (Th A on th lowr lft of th srn-shot indiats th zro volt lin; ah division is on volt). If th transistor was turning on hard, th dips would drop to almost zro volts. This transistor was not turning on vry hard at all. First faild attmpt to fix it: I first trid to rdu th ias rsistor from 2M to 1M2 so that th puls from th pik-up would turn th transistor on asir. I also lowrd th 850R rsistor to gt a it mor urrnt through th sond pik-up oil and hopfully gt a iggr push on th pndulum. This workd for a day thn stoppd. Th transistor had faild. Sond attmpt (this on workd): May th transistor was always a it flaky, so I rturnd all th rsistors to thir original valu and rmovd th C828 transistor. I ouldn t find anyon slling C828s nor ould I find muh information on thm. I trid rplaing it with a gnral purpos NPN transistor (a BC337 I had availal) and th lok workd wll. I had anothr look at th transistor olltor voltag and this tim I saw: Th transistor is turning on a lot hardr now, gnrating a strongr puls in th sond winding of th pik-up. I rplad th transistor on all thr loks and thy all workd. Pag 4 of 5

5 Sujt Fixing th Kanto Siki lok Author E. Bttio Not: I usd a gnral purpos BC337 to rpla th C828. I xpt any othr gnral purpos NPN transistor (lik a 2N3904) would work fin, though thr might a nd to adjust th ias urrnt (th 2M rsistor). You must arful rplaing th transistor with an quivalnt aus th pin arrangmnts might diffrnt. Th C828, th BC337 and th 2N3904 ar all diffrnt. S low: VIEW FROM UNDERNEATH BC337 2N3904 C828 In summary: Chang th apaitors, and hang th transistor. I had thm running on a nh powr supply for a wk or two ah to hk and adjust thir auray. Thr is a lad srw adjustmnt on th ak (thr is a marking on th lok housing showing th dirtion of adjustmnt). My original lok has n ak in my ar for narly two yars now, it is still running and I rarly hav to adjust th tim. Good luk, Eri. Pag 5 of 5