南京某烧友通过快递寄来一台DM500S接收机要求笔者帮忙给予维修,描述的故障现象是开机无法收视水平节目,机主怀疑是以U70LT1930(LTKS)为核心的电路有故障导致的,自己动手修理过可是没有排除故障,所以委托笔者维修。通电试机故障同描述一致,测L712输出端始终为11.78V。打开机器,目测Q60、F4、U70、C723和C724已经拆除,同时U70周围部分相当肮脏,如 Nanjing a Shaoyu sent by courier to a DM500S receiver requires the author to give help to repair the description of the failure phenomenon is unable to watch the level of boot shows, the owner suspected U70LT1930 (LTKS) as the core of the circuit is faulty, do it yourself Repair but did not rule out the fault, so I entrusted the author repair. Power test machine fault with the same description, measuring L712 output is always 11.78V. Open the machine, visual inspection Q60, F4, U70, C723 and C724 have been removed, while the surrounding part of the U70 is quite dirty, such as