Service Phone 13818806549 021-56102546 Contact Challenger 


 Shanghai Haier Air Conditioning Repairs Air Conditioning Service Telephone Telephone Shanghai Shanghai Haier Haier air conditioning repair points 
 021-22816736 
 A) site maintenance services 

 1, Haier air conditioning products from the sale date (with a valid Haier) in the three packs of free warranty period, more than three bags or three bags of validity within the responsibility of charging fees in accordance with the provisions of maintenance; 

 2, uniform repair, consulting, service hotline, 365 days to provide hotline services; 

 3, site service within 24 hours of urban, peri-urban areas within 48 hours of home services, rural, remote rural areas, home phone service appointment. 

 Haier air conditioning maintenance of Maintenance: The Department of transfer to another machine, there are several instructors have taken. Open the case and found 52 feet Manifold LA7688 socket weld, showing that it has had to be a good substitution. AV will be placed on the state air-conditioning, access to VCD audio and video signals, it really silent no map (blue screen). Shown in Figure 1, the measured time LA7688 (￡) pin voltage is 3v, indeed in the AV condition, ⑩ feet about 1V P Bu video signal, ⑩ feet of audio signal amplitude fluctuations, * pin voltage is 5V (* feet to the line detector output and consistency of 4.43MHz and 3.58MHz crystal switch side), indicating that LA7688 has signaled information - high level (1.3V when no signal is low level) o 
 Measured with the oscilloscope CPU (LC864912) * pin non 5VM line pulse, a signal that the state Av CPU did not get the signal (line pulses) and air conditioning blue screen error to squelch. Let air-conditioning in the TV state, Shenzhen, Haier air conditioning maintenance air conditioning cable connected to the signal, Fig sound normal, when measured LA7688 (hail) is 5V feet high, cpu @ feet 6VH, the line sync pulse, it appears that failure in the LA7688 (basin) feet to the identification between cPu @ pin signal generator circuit. The investigation, V250 emitter is open damaged. In the absence of transistor C536, substitution with the C1815, the test machine, AV appears acoustic state diagram, troubleshooting oV250 is to identify the signal generator circuit components. The role of the circuit is to provide pin CPU identification signal to determine whether the identification signal oCPU in two ways: first is to identify the foot under the DC voltage from the high and low to determine, and the second is based on identifying foot line pulse ( including the line sync pulse) to determine the presence or absence. When the CPU get a signal in the news, so that air conditioning noise figure in a normal state; when the CPU does not get the signal information, Shenzhen, Haier air conditioning maintenance points are whether you have no signal, all Squelch (including both screen and sound mute) . 
 Identification signal generator circuit TV AV state status and the public circuit. Generally, as long as the TV sound under normal map, you can not figure identified silent under AV and Tv, Av independent of the public circuit. However, just out of the unit to malfunction in the TV, Av public circuit identification signal generator circuit, people can not believe it. 
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