Hifonics Brutus BX 2005d

seankane · 2012-11-13 8:24 am

Its hard to read the silk screen but looks to be a R5 and a R5A?

If so is R5A the 1K ohm and R5 the 27K ohm?

Perry Babin · 2012-11-13 8:25 am

Do you have 12v on one side of R5?

seankane · 2012-11-13 8:29 am

On the one side of the 1K resistor which I think is R5 I have 13.50 vdc and on the other side nothing.

Perry Babin · 2012-11-13 8:31 am

I've found that high value resistors commonly fail. Replace it with something lower for testing. You can use a leaded resistor soldered across R5. Try a 10k or something similar. There will be almost no delay but it should let the relay engage.

seankane · 2012-11-13 8:42 am

I replaced R5 but I think its R5A can you look at the pic of the p/s driver board you posted. There is a 27K resistor that I think is R5 but I cant read the silk screen.

Still no engagement from the relay.

seankane · 2012-11-13 8:45 am

270K sorry

Perry Babin · 2012-11-13 8:57 am

Do you have 12v on one end of D4?

seankane · 2012-11-13 9:02 am

Perry Babin said:
Do you have 12v on one end of D4?

14.50 vdc one one end and .950 vdc on the other.

Perry Babin · 2012-11-13 9:05 am

OK. Well, C3 or Q3.

seankane · 2012-11-13 9:09 am

Ok well Q3 is brand new so gonna go after C3 but I dont have that value of capacitor laying around. I have some for Rockford amps like 10uf 63v guess its gonna be more days of waiting for parts.

Do you know the size of that 47uf 16v capacitor?

Can I use something instead to test?

seankane · 2012-11-13 9:11 am

oops just got it off and its a 100uf 16v

Perry Babin · 2012-11-13 9:16 am

You can simply remove it. That will eliminate the delay. I wouldn't connect speakers when powering it up. It could produce a loud pop.

seankane · 2012-11-13 9:23 am

It measured 89uf on the meter does that mean its defective since its a 100uf cap?

seankane · 2012-11-13 9:26 am

I accidentally shorted the emitter and collector of Q3 when doing some testing and the relay clicked. Does this mean Q3 is leaky and how could it be since its new????

Perry Babin · 2012-11-13 9:38 am

Shorting the collector and emitter should have prevented the relay from engaging by switching the other two transistors off.

89uf is within tolerance for most electrolytics (which are often ±20%).

Are you sure that the relay didn't click immediately when you powered up the amp?

Re-check to see if you still have 14v on both ends of the diode near the relay.

seankane · 2012-11-13 9:42 am

Yes I have 14.50 on both ends of D201 the diode next to the relay. The relay is not clicking when the amp powers up but if I short the emitter and collector it clicks on and stays on......I dont get it.

Perry Babin · 2012-11-13 9:52 am

How did you short the collector and emitter accidentally? They're on opposite sides of the body of the transistor.

seankane · 2012-11-13 9:56 am

The top pin and middle pin are both the collector, they are connected underneath the transistor. When I went to test the voltage on the emitter I accidentally touched the collector at the same time.

Perry Babin · 2012-11-13 10:26 am

Are you sure that you had the voltage on the base of Q3 right when you posted the voltages?

seankane · 2012-11-13 10:28 am

I replaced Q3 again with the same result no relay engage. I will check the voltages of Q3 again and re-post then to confirm.

Hifonics Brutus BX 2005d

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