Rockford Fosgate Punch 600a4

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Did some further checking. After first turn-on I got the following:

LM317
In: 29.1V
Out: 14.5V
Adj: 13.4V

LM337
Out: -12.9V
In: -29.1V
Adj: -11.4V

Is there anything to learn from those numbers? I also noticed the solder joints look cold/cracked on the 317, and I'm getting a high frequency vibration from, I assume, the transformer when I first power it on. I didn't notice that before switching power supplies.
 
Last edited:
Audio output from all channels still seems fine at low volume, and you're correct that the whine stops before the mute delay lifts. I reflowed the cracked looking solder joints on the regulators, and also some similar looking joints on the output fets. Still getting plenty of heat from the regulators. My measurements were slightly different, but that may have been my meter battery was dying.

M317
In: 28.5V
Out: 14.2V
Adj: 12.9V

LM337
Out: -12.5V
In: -28.5V
Adj: -11.1V

Hard to believe this could survive in a hot car environment. This was taken with about 77°F ambient with a light ceiling fan breeze
 

Attachments

  • 119124743_10158651863325138_7043328634606228434_o.jpg
    119124743_10158651863325138_7043328634606228434_o.jpg
    376.9 KB · Views: 58
Yes, but I was getting similar readings off the back of the heatsink.

Q6, Q8, Q13 are definitely heating more than Q5, Q7, & Q12. About 125°F compared to about 100°F.

U202 is heating as much as 117°F give or take, and similarly U402 next to it. It's difficult to get accurate readings. The other TL072 chips are getting warm also, but these are the hottest as far as I can tell.
 
Are you saying that the 300 series transistors including Q309 are heating, alone or are all of the Qx09 transistors heating?

Post a photo of the drive signal on the gate legs of one PS FET in each bank when the FETs are heating unevenly and when they are heating equally.

For the hottest op-amp, remove it or at least lift it's power supply terminals and re-check the heating of the adjacent op-amp to see if it's still heating up.
 
Q108, Q109
Q208, Q209
Q308, Q309
Q408, Q409

These are all heating, but maybe this is normal. Just trying to find any outliers that might indicate a problem. I don't have a scope, but I guess I need to get one if I'm going to try to figure this out without shipping it off to someone else.

I will try your suggestion of lifting the hottest op-amp. Thanks for your help, Perry
 
I lifted PIN 4 and PIN 8 of U402, TL072C. Before lifting those pins I was getting different readings on R43 and R44. I was getting about 40ohm on one and 37ohm on the other. With U402 PIN 4 & PIN 8 lifted they both read correctly at 20ohm.

Regulators are still heating to the same amounts as before. At 13.5V input I get:

LM317
In: 28.6V
Out: 14.2V
Adj: 12.9V

LM337
Out: -12.7V
In: -28.6V
Adj: -11.3V
 
There are two sets of 4 TL072 and 3 LM833 paralleled together on pins 4 & 8.

DC voltage on U201 TL072:

Pin 1: 0.57
Pin 2: 0.57
Pin 3: 0.56
Pin 4: -12.15
Pin 5: 0.48
Pin 6: 0.50
Pin 7: 0.50
Pin 8: 13.67

I get almost identical readings from U401 on the other side of the amp
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.