hifiaf
pfm Member
Tonight I recapped the fan boards, replaced the VBE tant on the amp boards (which I may have fouled previously), replaced the zener diodes on the reg boards, and de/resoldered all the connection to the XLRs. Also checked all my interconnects to make sure they're not mixing signal and ground.
I also checked the values on the over-amperage trim pots. The "good" amp has both of its pots set to 258 ohms (I got two identical readings and one 0 reading in the three possible pin positions). The "bad" amp had its pots at 220 and 240 respectively. I tried my best to get them to 258, but they wouldn't go that high. They would go from zero (all the way in) to 220 or 240 (halfway) and then back to zero as you backed them off completely. This may indicate a problem with the pots, or with my way of taking readings, or with the very concept of trying to take readings with them in circuit... In any case, I just put them back where they were initially.
I'll test the amps out tomorrow and see if any of this has made a difference!
I also checked the values on the over-amperage trim pots. The "good" amp has both of its pots set to 258 ohms (I got two identical readings and one 0 reading in the three possible pin positions). The "bad" amp had its pots at 220 and 240 respectively. I tried my best to get them to 258, but they wouldn't go that high. They would go from zero (all the way in) to 220 or 240 (halfway) and then back to zero as you backed them off completely. This may indicate a problem with the pots, or with my way of taking readings, or with the very concept of trying to take readings with them in circuit... In any case, I just put them back where they were initially.
I'll test the amps out tomorrow and see if any of this has made a difference!