D2 Powerhouse Earthquake amplifier. Power supply down.

[Perry Babin]

IRF3710Z is the only transistor I have had no problems with in any 4080 amp. The IRF3415 works in some but not all. After I found the 3170Z and it's been completely reliable with one exception, in MMATS amps but the users in my area insist on running all of them at a near dead short so I don't know if they'd be reliable with normal loads.

 

[rhempz01]

Isn't that how u run an amplifier? I'm kidding Jesus. Only one of the output are shorted, the amp was down because something spilled on it and brought down the output and the power supply. I have the 3415's but I can order the 3170z. I just want the amp to be reliable. The 3415 should work.

 

[Perry Babin]

If you use the 3415s, drive it without a load to see if you see anything strange happening in the carrier (rail-rail signal). Set the scope to 2ms. You don't want to see the individual pulses, you want to see them as a wide group.

 

[rhempz01]

I had two resistors start to smoke after I powered up the new power supply.. the two 10 ohm

 

[rhempz01]

Does anyone know the value of the small capacitors. In line with the 4424?

 

[Perry Babin]

I think those two resistors feed (separately) the power supply drive and the 4080. The one that burned may feed the 4080. Not sure on this. It's been a long time since I worked on one.

 

[Perry Babin]

What do you mean by 'in line'?

 

[rhempz01]

The small yellow hole through. One is directly next to it the other was broke in half and had no markings, well faded I thought it said 103-104. I just meant I the row of components.

 

[Perry Babin]

The one at the end of the 4424, it's marked 104 in photos I have. I have nothing on the other in that row.

 

[rhempz01]

So .1 63v should be good.

 

[rhempz01]

It didn't do this smoking before I removed the outputs? So I been checking for some sort of soder bridge or a reason for the current to burn the resistor?

 

[rhempz01]

So the new 4080 came in today as well as the irf3710z for the output section. The old 4080 had some diodes attached to it. Should I replace them on the new driver ic? If so what diodes should I use?

 

[Perry Babin]

What happened to the original diodes?

 

[rhempz01]

I have them they are epoxied to the chip.

 

[Perry Babin]

What is the number on them?

I have notes on one amp but the numbers I have (were correctly read from the diode) don't seem right.

 

[rhempz01]

The diodes are completely covered in epoxy. Unreadable. I reused them. At least tried to. Something popped right away. Not sure what it was. I printed out your 4080 scope pages. Pin one doesn't look right. And I should of tested the socket voltages before placing the new 4080 in

 

[rhempz01]

The resistor isn't smoking anymore I also replaced them. So maybe the 4080 is working.

 

[Perry Babin]

Does pin 10 look OK?

What's wrong with the waveform on pin 1?

 

[rhempz01]

So I installed the diodes on the new 4080, do I need the rectifiers in curcuit to test that the new one is working. I have the sheets of what the 4080 drive on each pin should look like. All I did was power it up and test pin 1 and something popped. Pin 10 is no better I can find a clean drive signal. And the 4080 is getting hot

 

[rhempz01]

Without 4080
1. 11.83v
2. 12.10v
3. 0.3v
4. .4mv
5. G
6. 5.7v
7. 5.76v
8. .5mv
9. .4mv
10. 11.83v
11. 5.76v
12. 5.74v
13. 10mv rises
14. .4mv
15. 12.05v
16. 12.11v
17. .4mv
18. 4.2mv
19. 5.72v
20. 5.43v