Directed 350D

[S Merlington]

Relay is not clicking on ..

On the diode I get 13.89 on 1 side and 8.49 on the other side of it and 5.30 across it .

Any ideas or is there a common problem with these amps?

 

[S Merlington]

Does anyone know if the 20 pin IC controls the regulated voltages ?

I'm getting 10 volts on pin 8 of the opamps but only getting -0.54 volts on pin 4 of the opamps ..

 

[Perry Babin]

It's possible that no one knows anything about that model but could help if it's similar to another, more popular amp. Posting photos in the first post can save a lot of time.

 

[S Merlington]

Sorry i know ive been told a 1,000 times about pics..

Just have alot going on right now..

Heres a few pics of the board ..

I know D205 is out of the boar right now for testing alo gonna replace the cap thats melted from someone else's attempted repair..

D205 is testing good and i also replaced it still get no voltage on pin 4 of the opamps

 

[Perry Babin]

Do you have -15v on pin 4 of the inline op-amps?

 

[S Merlington]

No getting the same reading on those -0.54

 

[Perry Babin]

What's the resistance from pin 4 to the primary ground?

 

[S Merlington]

10.29K ohms

 

[Perry Babin]

Pin 4 to the RCA shields?

 

[S Merlington]

0.04 ohms

 

[Perry Babin]

This amp may not have a negative supply. Try plugging a grounded signal source into the amp, Does that make a difference?

 

[S Merlington]

Plugging in a grounded signal source drops the voltage to 0.02 volts on pin 4 ..

Relay still doesn't engage

 

[Perry Babin]

The voltage on pin 4 is OK.

Do you have rail-rail oscillation on the outputs?

 

[S Merlington]

Yes

 

[Perry Babin]

Which transistor has its collector connected to the low side of the relay coil?

 

[S Merlington]

Q502,Q503 both collectors connect to the low side of the relay coil I replaced both of them relay still doesn't engage

 

[Perry Babin]

If there is a PNP transistor with its emitter connected to the base of one of those transistors, pull it. Does the relay engage?

 

[S Merlington]

Replacing Q501 A1266 made the relay engage ..

Amp is working ..

Thanks for your help ..

 

[S Merlington]

Got this amp back ..

The guy said when a song hits a low bass note the fuse on the amp
Will blow and after the amp has been playing awhile
It will lose output 1 min it will be loud and the next the output is cut in half ..

Any ideas what might cause this ?

I'm just trying to get a few of these finished up so I can take a break from repairs for lil bit and work on my house remodeling it

 

[Perry Babin]

An intermittent input signal could cause the level to change. It could also be an intermittent connection to a speaker. Can you replicate the problem on the bench?

Is the fuse the correct size? Was the same size fuse holding before the amp was repaired?