High LG2080 power amplifier power on indicator lights relays do not snap-no sound -Service Manual Download|Circuit Download|Download Drawings|schematic download|route map download|free download user manual

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High LG2080 power amplifier power on indicator lights relays do not snap-no sound

Time：2015-06-01 08:09:16 Source：Network Author：Unknown Clicks：1492

The relay contacts are free. If the amplifier level lost load, current gets smaller, you delay subsequent appliance to snap. If the reason for power flow (for example, the input signal is too strong) is not ruled out, then repeat the above process until input signal decreases.

Symptoms of this machine is to protect the LEDs stay lit, and V6, V7 multivibrator is also connected. D6 anode voltage measured is very low, welded to D6, protect led is blinking, indicating normal V6, V7 and its peripheral components. Suspected V5 has been penetrated, removed V5, c, e, between the resistance of only 36 ω, replace the V5 have become common after the protection led flashing after a few seconds, but a speaker power on the sound, and there is no relay is snap "da da" sound. Relay coil voltage measurement is about 13V, why doesn't relay closing it? V5 c, e of short-circuit, the relay does not snap, it appears that relay has gone bad.

Removed found after careful observation of the relay, the relay has a set of contacts in sintered together, cut with a knife and plastic. Next in the experiment found that as long as the contacts in the relay reset spring elastic weakens, or with 15V voltage relay could reliably attract. The failure reason is the relay sucks and timely action force gets smaller, estimates is magnetic iron core capacity resulting from a decline. Previous experiments, reduced spring force is in fact indirectly improves the absorption of iron core collection strength.

Change circuit relay electrical diagram j's copper skin cut off at the top of the coil, changed the coil wire at the top to a point, in order to improve the power supply voltage. Power test, relays can be reliably absorbs, but over time V5 fever bad, for safety's sake, the V5 C2383 replaced transistor.

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