Hifonics Brutus 1500 hip 4080 issue

[Triviumfan4]

C16 was exploded initially and replaced

 

[Perry Babin]

Measure the resistance across D205C and D206C and post the readings.

 

[Triviumfan4]

Don't see a d206c?The two d205c's(assuming one for each side) measure fine in circuit in diode check in one direction(.06).
Should we pull and check and or is the 206 supposed to be near the same area?I see it nowhere.

 

[Perry Babin]

0.06 is not good. Check on resistance. They should both go towards the mega-ohm range.

 

[Triviumfan4]

Sorry I meant .6...There both 205 in this amp?.Anyhow,with red probe on anode/black on cathode its 4.5k after it settles down.Probes reversed,about 5.6 k after many seconds when it settles down.Both still in circuit.

 

[Triviumfan4]

I removed one and checked it.Its .6 from anode to cathode and 0 the opposite way.If this helps.

 

[Perry Babin]

That sounds OK. The difference is probably in the way your meter determines the resistance.

Is the other 10 ohm resistor within tolerance?

What is the DC voltage across both 10 ohm resistors with the amp on?

 

[Triviumfan4]

Both within tolerance.Burnt one has 6+vdc across and other has +1vdc across.Seems like a problem lol.

 

[Perry Babin]

Are you sure that C16C is the correct value and voltage?

 

[Triviumfan4]

Perry,I feel like a total dumbass now.You just nailed the problem(really appreciate it)
The original cap was a 153h100.I had a 104j100 in that spot.I just swapped what I'm assuming is channel a from channel b and the resistor heat transferred to the other 10R resistor.I did order the right ones but don't have them yet.Can you explain why a fraction of a NF made such a chance?
I've over the years on various things used higher UF caps with no problems.I do refrigeration and change caps all the time without problems.Of coarse this is commercial related and not electronics based.If its to much to ask I can try to read about it on the net.
Thanks again

 

[Perry Babin]

The increased capacitance allowed more of the carrier waveform to pass through the capacitor and resistor. It's like increasing the value of the capacitor for a high-pass crossover for a tweeter. The increased capacitance would allow the tweeter to receive more power and possibly blow it.

 

[Triviumfan4]

Sorry but I have a couple more questions..sorry
What's the potentiometer for (vr12) I believe I may have have came a crossed it in the tutorial.A lot of stuff to try to remember.
Also, this thing draws about 1.5 amps.Also from rca ground to speaker ground is 32 +vdc?
And 166K from rca ground shield to amp ground lug? Perhaps another issue or something I don't understand?

 

[Triviumfan4]

Also has 100hz wave on all 4 speaker terminals.And every speaker terminal to ground has 32+vdc

 

[Perry Babin]

VR12 is the DC offset adjustment.

The speaker terminals are at 1/2 of rail (both positive and negative).

The input isn't referenced to any grounds in the amp. It's essentially a balanced input.

 

[Triviumfan4]

I understand hip4080 amps have half rail voltage on speaker terminals.Just wasn't sure about the rca and all 4 terminals having output signal.

 

[Triviumfan4]

Awesome.This is my first time playing with a hip4080 design.Thanks for the help.I'm gonna put the hammer to it and see what happens.

 

[Triviumfan4]

I'm so sorry for all the questions.Think there still may be a problem.The original burnt resistor still gets fairly hot.Just take a minute longer now.The other 10R stays room temp.
There's some static on the output with a speaker connected.The output is ever so slightly distorted.
Here's some pics of the low/high side outputs from the channel with burnt resistor.Actually both channels look the same.No input signal on these photos.

 

[Triviumfan4]

Here's the pics

 

[Perry Babin]

Current draw of less than 2 amps is OK.

The waveforms look OK.

What are you using for an input signal?

 

[Triviumfan4]

Standard head unit with Cd.Head unit and amp power supply grounds are connected.