directed 500/2

[mike49504]

Im working on a directed 500/2 amp one of the mosfets was bad also a output was also bad. So i pulled both bad parts from the board and replaced the tl494 in the amp. When the amp is powerd up the power light just blinks every few secs wondering what i should check at this point

[Perry Babin]

Do you see a pulsing of DC on the bridging speaker terminal of any channel as the amp tries to power up?

[mike49504]

How do i check that agin sorry been awhile since i worked on amps So wondering how do i check to see if i have pulsing dc on the bridge terminals

[Perry Babin]

If you have a scope, simply touch the probe to the speaker terminals. If you're using a multimeter, touch one probe to a non-bridging speaker terminal (any one) and touch the other probe to the various bridging terminals as the amp tries to power up.

[mike49504]

i checked and yes it does have pulsing dc on the terminals

[Perry Babin]

I expected it on one, possibly. Do you have DC on all of the channels?

Did you use a meter or a scope?

[mike49504]

I used a meter and only have pulsing dc on the left channel nothing on the right channel

[Perry Babin]

Did you check or replace any of the output transistors in that channel?

[mike49504]

i checked the outputs in that channel one of the tip35c's was bad so i took it out but havent replaced it yet thought maybe i could power the amp up without it being there to see if anything else was wrong

[Perry Babin]

If it has more than one TIP35 in that channel, you can remove the defective one and the amp should operate normally if there are no other problems.

Did you check the driver transistors (for both the 35s and 36s) in that channel?