HIP4080 amp - EVO 2200.1

[chrisg4]

I've replaced the DC offset pot, I was able to bring down the offset to 0v

 

[Perry Babin]

What value pot did you use? The diagram shows 500 ohms but you previously gave it as a 500k.

What value was installed?

Did the pot actually affect the DC offset?

VR9 on your board?

 

[chrisg4]

500 ohm, my mistake I meant 500ohm (I ordered a replacement)

501 ohm was installed.

yes, it did.

VR9, yes the same one.

 

[Perry Babin]

How different is the circuit for the jfet?

I don't see the pot SVR1. What else is different?

What's the DCV on pins 8, 9 and 10 on U9?

 

[chrisg4]

JFET circuit
D: connected to Pin14 5470
S: connected to pin3 of 5470 as per the diagram
G: driven by Pin7 of 5470

will post voltages later on, we have an electricity outage

pin8 & pin9 are bridged on U9

 

[Perry Babin]

load-shedding?

 

[chrisg4]

yes, unfortunately... the joys of South Africa

 

[Perry Babin]

I hadn't heard of that in years. I didn't know it was till a problem.

When you get power back:

U9 on 9001 diagram (left)
On your amp (right side)
Pin 1: =
Pin 2: =
Pin 3: =
Pin 4: =
Pin 5: =
Pin 6: =
Pin 7: =
Pin 8: =
Pin 9: =
Pin 10: =
Pin 11: =
Pin 12: =
Pin 13: =
Pin 14: =

 

[chrisg4]

its an ongoing issue for SA

Pin 1: = 6v
Pin 2: = 6.5v
Pin 3: = 6.5v
Pin 4: = 11.7v
Pin 5: = 11.7v
Pin 6: = 0.02v
Pin 7: = 10.9v
Pin 8: = 5.9v
Pin 9: = 5.9v
Pin 10: = 5.4v (amp draws current limited to 4A)
Pin 11: = 0v
Pin 12: = 6v
Pin 13: = 5.9
Pin 14: = 5.4v

 

[Perry Babin]

That doesn't answer post #128.

 

[chrisg4]

apologies misunderstood #128

 

[Perry Babin]

Are you sure that you have pins 8, 9 and 12 correct for your amp?

I'd expect the audio in to be on the same op-amp section as the bridged pins.

 

[chrisg4]

Discovered a solder bridge on the 5470 Pin4 & pin5

will remove and test

 

[chrisg4]

Amplifier is fixed after replacing 5470 ic