Hi All, just finished assembly of my latest K2/100 (the fourth K2 I built) and for thefirst time I'm having trouble getting things running.
During testing I noticed a strange behaviour: Some of the option modules are getting lost sometimes and being displayed as "not inst". Tracing things down I found the AUXBUS being pulled down to 1.9 V whenever the KDSP2 option is plugged in. K2 is working so far even with this low AUXBUS voltage, but I think it's no sufficient voltage for reliable operation. With KDSP2 being unplugged the AUXBUS voltage is at 5 V. KDSP2 itself is working (I have audio, LED lightening for 0.5 s on power- up). Switching the audio filters via the AFIL button is also possible, but the K2 displays "stnot in", that is the "not inst" message shifted in a strange way. The KDSP2 menu (DISPLAY key) does show up only occasionally after powering-up the K2 and pressing DISPLAY. If it gets lost, it's lost until switching the K2 off and back on. Tracing the AUXBUS circuit on KDSP2 I found, that: AUX2 is 0 V AUX3 is 1-2 V I think AUX2 = 0V enables the AUXBUS driver Q2 for data transmission and this might be causing the trouble. But I'm not sure wheter I understand the circuit correctly. Is it true, that AUX1 = AUXBUS read AUX2 = AUXBUS drive enable inverted AUX3 = transmission data What should I do next? I fear the AUX2 output of the KDSP2 MCU (U1) is defective making it impossible for the module to send data to the AUXBUS and pulling it down continuously. Any other suggestion? Your help is very appreciated. VY 73 de Marcus, DL1EKC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
