Rockford Fosgate 600.5

[mike49504]

U1620:12.42
u1620r:-7.06

u1620 0

u1620r:0

 

[Perry Babin]

DC voltage on 9/10 of the 494?

DC voltage on the gates of the power supply FETs?

 

[mike49504]

TL494
9:0
10:0

Gate legs of fets:0.5

 

[Perry Babin]

It's not powering up. Could it be in thermal protect again?

 

[mike49504]

I measured the resistance on the thermistors and get nothing near 0 ohms.

I have a 800a2 board robbed of parts can i use the thermistors off that board to see if i can get this thing to power on?

 

[Perry Babin]

Desolder one leg and measure the resistance if you think they're defective. After they cool, they will read near 10k.

Post the voltage on the 494 and the 339 if they're OK.

 

[mike49504]

TL494
1:0.53
2:4.22
3:.06
4:4.92
5:1.51
6:3.37
7:0
8:13.20
9:0
10:0
11:13.20
12:13.20
13:4.98
14:4.98
15:4.98
16:0


339
1:0
2: bounces all over the place
3:13.20
4:.09
5:2.49
6:4.33
7:4.98
8:4.98
9:bounces all over the place
10:4.98
11:8.20
12:0
13:0
14:bounces all over the place

 

[Perry Babin]

According to the schematic diagram, 1, 2 and 13 are directly connected. Confirm that you read 0 ohms between those pins on the 339.

 

[mike49504]

Yes i have 0 ohm between them 1,2,13

 

[Perry Babin]

Re-check the voltage on the 339. If 2 was not steady and 1 and 13 were steady, there was an error in the readings.

 

[mike49504]

1:bounces
2:bounces
3:13.20
4:.08
5:2.38
6:4.34
7:4.98
8:4.98
9:bounces
10:4.98
11:8.20
12:0
13:bounces
14:-0.62

 

[Perry Babin]

Lift Q2 to see if the voltage on the 339 stabilizes.

 

[mike49504]

pulled Q2 and voltage on pins 1,2,13 are 4.92 volts

Pin9 is 0.21 volts

 

[Perry Babin]

Voltage on rectifiers?

Voltage on pin 4 of the 494?

 

[mike49504]

Pin 4:0.10

U1620:31.08

U1620r:-29.47

U1620:0

U1620r:0

 

[Perry Babin]

The supply still doesn't appear to be working. Post the voltage on all of the pins of the 494.

 

[mike49504]

Tl494
1:2.36
2:2.34
3:3.52
4:0.10
5:1.51
6:3.36
7:0
8:13.12
9:0.27
10:0.32
11:13.12
12:13.12
13:13.06
14:4.98
15:4.08
16:0

 

[mike49504]

Perry,

i read the post where u said 540n's give you problems in fosgate amps. I used the 540n's in this amp should i take them back out and see if this amp will power up and produce voltage at the rectifiers?

I know i replaced outputs in a rockford 451 S with the 540n's and the guy has burnt the same 2 outputs up 3 times now so im switching thoose out with the 540's

 

[Perry Babin]

It looks like the power supply is producing the correct rail voltage. Are you sure that you don't have any voltage on the second 2 rectifiers?

If you don't, do you see a ±40v square wave on the outer legs of the second set of rectifiers?

 

[mike49504]

What would i set my scope at to test it?? Also finally got my scope back and my sine wave generator