Rockford Fosgate 2500.1bdcp, questions.

[rhempz01]

I have a Rockford Fosgate 2500.1bdcp. I can't find a fault within the amplifier it powers up fine. Nothing seems to be shorted. Is 9amps a normal idle current draw for these amplifiers?
All the voltages at the regulators are spot on.
When I apply a 40hrtz signal the amplifier flashed into thermal protection.

 

[rhempz01]

U102. ......... U101
1.) 6.490 ......... 4.985
2.) 6.567 ......... 6.479
3.) 12.26 ....... 12.26
4.) .419 .. ..... .067
5.) 3.005 . ....... 2.938
6.) .058 ......... 2.498
7.) 2.939 ......... 7.08
8.) 4.019. ......... 4.091
9.) 4.999 ......... 4.639
10) 4.999 ......... .510
11) 7.58 . ........ .001
12) .001 ......... 0.00
13) 7.75 ........ .001
14) 7.74 ........ 5.065

 

[Perry Babin]

What's the number on the PS board?

 

[rhempz01]

1325-52837-06

 

[Perry Babin]

I don't have anything on that board. Is it possibly a 52873?

 

[rhempz01]

Yes it is perry.

 

[Perry Babin]

What's the DC voltage on the emitter of Q190?

 

[rhempz01]

7.52v

 

[seankane]

9 amps is not normal.

 

[rhempz01]

I got the current down now. Changed the lm317- lm337 Its half of that. It still flashes into thermal protection.

 

[Perry Babin]

Was the 7.52 before or after the regulator change?

If before, did it change?

Does the rail to rail oscillation of the output shut down when the thermal LED lights up?

Does the PS shut down when the thermal LED lights up?

Is the fault just a flash then all returns to normal?

 

[seankane]

In the beginning of the post you said the regulated voltages were spot on. You changed the regulators and now the current draw is down. You have me curious now. I wonder what changed by just changing them?

 

[rhempz01]

not sure sean, the four regulators were right at the voltages i have in the guide. now they are not, that 7.65v i have at the emitter is definitly wrong. it falls slowly @4.37v if i leave the amp running for awhile.

 

[seankane]

I just dug out an old amp from a year ago that has large current draw. We may have the same problems...lol

 

[rhempz01]

Lol,, ok so i have the proper voltages at (q2000-q2012) i think thats right. The output regulators. The lm317 was causing the current draw and that is under control. When i just started the amplifier it was working with audio. Then after it warms up back to thermal protection in and out.
Before that at the emitter of q190 i have 21.55v

 

[Perry Babin]

How warm does it have to be to cut out?

Have you tried heating/cooling areas to see which are sensitive to temperature?

 

[rhempz01]

Perry i did not see your post.
7.52v was before. I knew something was off.
I will check and answer the other three questions.

Yes the power supply cuts off then on again. And the outputs stop oscillating.
I haven't pulled them yet and check them.
the entire amplifier looked so freshly refurbished

It isn't heat. If i touch the RCA shield with a RCA its instant. If i probe the regulators for voltage it sometimes happens. It always flashes to thermal protection when it starts up then to on, if the rca are already plugged in it sometimes will stay on for a minute.

 

[seankane]

Have you checked the thermistor inside the transformer on the board. I had one in once that was doing weird thermal stuff and it was a cold or overheated solder joint on that thermistor inside the transformer on the board.

 

[rhempz01]

Yes i touched them up. I too have had that a few times sometimes it was the only thing wrong with the amplifiers

 

[Perry Babin]

Does your signal source shield read 0 ohms to the 12v power supply ground terminal?