Soundstream Rubicon 2500.1 part identification

[joselorenzo]

I just started to rebuild the power supply in a Rubicon 2500.1 and I found a burnt resistor. R8 anyone know the value of the resistor that belongs here?

 

[rhempz01]

Highside

 

[rhempz01]

1k 1watt, thanks

 

[rhempz01]

Having some issues with setting the scope to veiw the low side.

 

[rhempz01]

Question, if I see the 50hrtz on all the gates of the output transistors, drive is present. Withing a few seconds gain is all the way down the high side output transistors heat up, I tested all the driver transistors, in tester and with ohms for leaking. Would it be the torrid, one looks raised? Or the octacouplers?

 

[Perry Babin]

In differential mode, is it still noisy? Is that scope that noisy on everything?

 

[rhempz01]

No perry if I look at say the drive signal on power supply it is no. It's clean. Most output signals. I just look at them like that.

 

[Perry Babin]

1. If you look at any other signals in the audio section, do you get the same noise?

2. If you probe the audio ground, do you get the noise?

3. Did you check the signals in differential mode?

 

[rhempz01]

Yes perry differental mode, and the noise starts at the a/v Jack's, it's possible it's from the main ground.? If I test the DC voltages at the output placements. high side I get 6.51vdc on the gate
80vdc source
3.45vdc on drain.
Low side
Gate -71.6vdc
Source 3.45vdc
Drain -78.4vdc

 

[rhempz01]

Could use help, the driver transistors heat up quickly as well. The a1277, c3228. Replaced them still the same. The noise is only on this amp.
I did get the octacouplers u suggested perry.
And a new set of irfp264.
I pulled one leg of all the gate resistors and tested them and the diodes, all within tolerence.

 

[Perry Babin]

Does your scope give the same really noisy signals on the class D output section of other amps or is it just a problem with this amp?

 

[rhempz01]

most if i test this amp right at the jacks it remains the same.

 

[rhempz01]

Which amp has this identical board?

 

[rhempz01]

So transistors Q43, Q42 Heat up very quickly after powering up the amp. No output transistors in curcuit.

 

[rhempz01]

Confermed the noise is only on this soundstream amplifier. Went to the shop and tested the audiopipe class d amp and it's perfect clear 50hrtz on the pads with no output transistors. So it's not the scope.

 

[rhempz01]

Does anyone know of a similar amplifier that uses this same driver /design I can purchase to figure out what is going on with this one?

 

[Perry Babin]

Many amps use this basic design. There are fewer that use the board with the TO-220 drivers. The Planet Audio BB2400.1 uses this driver board. I don't know of any manufacturer that will sell the boards. You may find some on ebay.

The forum member jacampb2 may have something that you can use for testing.

 

[rhempz01]

That should be fine perry just going to order a working unit to make comparisons to. I used the octocouplers you suggested and they worked. It stopped the small signal drivers from over heating. But the high side output transistors still heatup within 10 sec of turning on the amplifier. Same noise appears right at the RCA? I found that someone repaired the underside of the rca grounding leg with soder. So I reworked that connection. Still the noise persists

 

[Perry Babin]

If you switch to slave mode, does the noise remain at the output of the amp?

 

[rhempz01]

No same results noisey. I have here a brand new rub1600.1 and it the same noisy output section. Drivers are super hot in it as well right away? It using ltv827, but same layout just smaller.