CTS 4200 4 channel CROWN power amp I changed 2 output transistors on channel 1 they were both bad but I am still seeing a fault on channel 1. I tried changing the relay for that channel but the relay doesn't seem to be the problem. Is there something that I need to do with the small embedded computer system on the board to finish up this repair?

blown channel 2 =, could be output transistors or drivers transistors for channel 2

It sounds like your output transistors are bad or power supply problems. You will need to have it serviced unless you know about electronics and how to repair them. Do not attempt this yourself unless you know what you are doing. It could be fatal.

the output transistors are 5 to 10 bucks each for most.there are 2 or 4 on each channel,depending on brand .some high end amps have 10 transistors on each channel.mosfets are a different story as they run 20 to 50 bucks each and there is 2 or 4 on each channel.some amps use a big IC instead of transistors.those have 16 to 24 pins and are easy to change. Those IC are 25 to 75 for a stereo one like stk4141 etc.since most yamaha amps are dc coupled,when the output transistors go,they take out the driver transistors as well.If you replace the outputs and the drive transistors are shorted,they will blow the outputs again.

if ur output power amp is defective u will have that problem - meaning the moment u connect load across it it will go into circuit protection to limit/stop excessive output current. make sure the speaker terminals are connected to +/- output terminals. in bridge mode use only channel 1 and that too with 4 ohms speaker only otherwise amp will clip. considering all connections are okay if it still clips when speaker is connected, u have a faulty power amp section. this the way ur amp is designed

Most likely one or more pairs of the output transistors is shorted. The amp is attempting to drive a signal into a 0 or low ohm load. This unit should see a service center for repair.

Dan

Before asuming it is the power transistors check the power on relay first as mine had the same proble and it was because of the Relay that did not switch on the one channel or amp (remember this is a power amp and consist of two mono amps)

timy check the speaker conections before condeming the amp

This in an indication that there is a problem detected in the final output stage of the amp. This amp will require service. Crown amps are not teh most straightforward designs and should not be repaired by an inexperienced tech. There are high voltages present inside these amps that can be dangerous. The typical cause of this symptom are bad output transistors. Expect a parts cost in the $40 range plus the local labor rate.

Dan

Look first at the output transistors. Those are the most likelt defective parts. Due to the odd design of the output section, Crown amps are difficult to repair. If you get lucky, only the outputs are smoked. Also, make sure that you change all of hte transistors for the channel that has a bad one.
Dan

Power Output (1 kHz*) Stereo Bridge-Mono 8 Ohm 4 Ohm 8 Ohm XLS 802 500W 800W 1600W XLS 602 380W 600W 1200W XLS 402 300W 450W 900W XLS 202 200W 300W 600W *1 kHz Power: refers to maximum average power in watts at 1 kHz with 0.5% THD. It depends on the impedence of the speakers. Carfull as you could burn up this amp if you exceed the resistance rating on it. Go here on all of the specs of this model of crown amps. http://www.crownaudio.com/amp_htm/xlsspec.htm Good Luck