Thanks for the add. A friend gave me this amp that does not work, it just crackles when I play. I am a guitarist and dabble in electronics. I attached the schematic. I have +/- 16V after R144 & R145. I plugged the guitar in the poweramp in jack as someone suggested on another thread and nothing happens. The LEDs on the panel work and speakers are good. The resistors look to be soldered OK, no other loose solder joints that I can see. Can someone tell me what I should check next? I'm trying to understand how to check the ICs. This was on another thread: "Check if you have +/- 16V on the IC's pin 8 and 4.". I have 32V across pin 4 and 8 on all ICs. For U7 it looked like I should be getting 16V at pin 1 & 7. I measured across pin 4 & 1 and 4 &7, and got 1.4V and 32V respectively. Am I measuring across the right pins?
I have (almost) this same amp. Your basic Fender SS 212 combo. But I don't think it's actually a "Frontman." (It's buried deep in my storage, or I'd just look.)
Anyway, it's problem was the worn out and/or corroded "Power Amp In" socket contact. Take a simple guitar cable, or pedal patch cord, and plug from "Pre-out" to "Power-in", and see if it comes to life. Mine did.
The red arrow was the bad contact.
Anyway, it's problem was the worn out and/or corroded "Power Amp In" socket contact. Take a simple guitar cable, or pedal patch cord, and plug from "Pre-out" to "Power-in", and see if it comes to life. Mine did.
The red arrow was the bad contact.
