Pioneer PD-F1007 Service Manual - Page 53

PD-F1007 Disc No. 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 DCNT DPOS Disc No. 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 DCNT DPOS Disc No. 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 DCNT DPOS Disc No. 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 DCNT DPOS Disc No. 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 S.L 305 306 DCNT DPOS S.L (304): SINGLE LODER Disc No. 307 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 DCNT DPOS Relation between input port DCNT, DPOS and position of the mechanism 2. Position relation between position of the rack mechanism and photocell for disc detection The relation between these two positions is as follows. Position of the mechanism Photocell for detection Fig.: The rack seen from above The position of the mechanism and the photocell for detection are offset by a distance corresponding to 9 discs. Accordingly, the photocell for detection sees the disc number 9 discs before the position of the mechanism. Example: Disc No. at the rack position : Disc No. 100 Disc No. seen by the photocell for detection : Disc No. 91 Note: The rack has 307 slits, but the slits 301 to 303 and 304 to 307 are the space for the side of the single loader and are not used. Disc detection also is not performed for them. 3. Disc Detection Method 3-1 In Regard to the Disc Detection Method Disc detection is performed after stabilization of the rotation speed after rack rotation start and completion of acceleration. (After start of rotation, detection starts after feed of 20 discs.) The input ports DCNT and DISC of the microcomputer are used for disc detection. Port Explanation : DCNT : As described above. DISC : Input of the disc detection result by the photocell for disc detection. Input value "H" : No disc, "L" : Disc present 3-2 In Regard to the Disc Detection Timing C DCNT DISC A (8msec) B (16msec) 1 The microcomputer looks every 1 msec at the status (H or L) of the two inputs DCNT and DISC. 2 8 msec (A in the figure) after the drop of DCNT (C in the figure), the last 17 DISC inputs (B in the figure) are checked. A disc is assumed to be resent when even one of them is "L". 3 No disc is assumed when DISC was "H" all 17 times (B in the figure) in 2. Note: In regard to the drop ( ) of DCNT For looking at the drop or rise of DCNT, it is necessary to check DCNT every 1 msec for "H" or "L". "H" = "L" means a drop ( ). "L" = "H" means a rise ( ). For the timing, either one of the following A and B can be assumed. Accordingly, the point where a drop is found differs by max. 1 msec for A and B. Thus, using the above figure, it can be said that the time from finding that a drop has occurred until starting to check for disc presence (A in the above figure) becomes 8 to 9 msec. 1msec "H" "L" A 1msec "H" "L" B 53