Thule-PA150B-pwr-si8 维修电路原理图.pdf

Thule Audio ApS Thule Audio ApS Telephone: Internet: Bank: Den Danske Bank A/S Giro account no.: 6 96 72 13 Hrkr 14 +45 44 94 6000 www.thule- Account no.: 3140 255793 2730 Herlev Telefax: E-mail: Denmark +45 4494 6880 thule-audioemail.dk S.W.I.F.T. address: DABADKKK CVR/VAT no.: DK 13 48 45 97 Herlev, 15. Jan. 2004 Repair procedure for older versions IA150B and PA150B rev.8 Repair procedure for older versions IA150B and PA150B rev.8 The main problem in over 90% of the repair cases concerning these unit types has been that the electrolytic capacitors originally used dried out relatively quickly and caused internal oscillation similar to the IA/PA250BmkI problems as well as overheating voltage regulators, which in turn created multiple faults ranging from humming and switching noise to total AC burnout of resistors and capacitors. The solution is therefore based on preventing the drying out and the following oscillation from occurring in the first place. This is ensured by using ceramic capacitors instead of electrolytic capacitors that cannot dry out, since these do not contain liquid. The original specification featuring normal type capacitors capable of work temperatures up to 90deg C should have been fully adequate, since the main board temperature never rises above approximately 60deg C. The theoretical lifespan was therefore originally conservatively estimated to be not less than ten years. The following electrolytic capacitors marked red need to be exchanged to the mentioned ceramic capacitors or tantal capacitors marked greenmarked green: C17 117 344 changed from 3u3 50V to 220n 50V220n 50V C18 118 345 - 349 352 changed from 3u3 50V to 2u2 35V Tantal2u2 35V Tantal C346 347 changed from 3u3 50V to 100n 50V 100n 50V C348 350 changed from 3u3 50V to 470n 16V470n 16V This should according to R&D be the ultimate solution. It has been tested thoroughly in laboratory conditions, where the test units have been provoked in several abusive ways including high work temperature and higher voltage without boiling or oscillating. IA and PA150B now appear to be completely up to standard in terms of longevity compared with the rest of Thules amplifier programme. We sincerely hope R&Ds efforts will be of use to you all. Please note that these revisions are only useable on ver.8 Please note that these revisions are only useable on ver.8 (todays standard, changed in 1999). Earlier versions should have their main boards changed if oscillation has occurred. These component changes have now been implemented in production. RadioFans.CN 收音机爱 好者资料库