Hi all, I thought I'd post this up here before I delve into it any further. I've tried a lot of the component checks mentioned in other threads with similar issues, but so far can't find any faults. I ought to say the CA-710 in the UK is a CA-610II elsewhere in the world, and I've worked with the service manuals and diagrams available online for this model.
The amp was in the garage over winter (not ideal I know), while I made the time to make up repairs to the pre-amp board (broken tracks) and the volume control board (more broken tracks). I managed to fix these problems quite successfully, but after the repairs the amp only very reluctantly came out of protection - the relay would buzz for a few minutes before finally tripping, and everything would be fine (and sounding great I should add). Then after a random number of minutes of working fine, the protection would trip out again. This has progressively got worse to the point where it now won't come out of protection, unless the volume is turned right round to 3 o'clock (at which point the meter needles head straight to maximum). The relay will click on and off immediately the power is shut off at the switch though.
Before the amp was despatched to the garage the protection was getting very slow to trip on and off, so I'm suspecting a capacitor on the power supply side of the relay. Am I right in thinking this is probably the case?
Capacitors C579-584 inclusive have been changed (I already had some in stock so changed them anyway), and I'm about to change out C576 (this one looks very "fat" in its sleeve so I have some on order). I guess I'm going to slowly re-cap the entire machine regardless, but I'd like to at least have it working whilst I'm doing this, so any ideas for what else I'm missing?
So far I've checked all resistors especially fusible ones, and all are well within range. All circuits appear to be continuous where they should be, eliminating broken tracks/bad solder joints etc, but any dodgy looking solder joints have been re-soldered anyway. I haven't pulled and tested any transistors yet, but that'll be my next job if nobody has any other suggestions.
Anything else for me to check chaps? I bet I've missed something really obvious... :scratch2:
The amp was in the garage over winter (not ideal I know), while I made the time to make up repairs to the pre-amp board (broken tracks) and the volume control board (more broken tracks). I managed to fix these problems quite successfully, but after the repairs the amp only very reluctantly came out of protection - the relay would buzz for a few minutes before finally tripping, and everything would be fine (and sounding great I should add). Then after a random number of minutes of working fine, the protection would trip out again. This has progressively got worse to the point where it now won't come out of protection, unless the volume is turned right round to 3 o'clock (at which point the meter needles head straight to maximum). The relay will click on and off immediately the power is shut off at the switch though.
Before the amp was despatched to the garage the protection was getting very slow to trip on and off, so I'm suspecting a capacitor on the power supply side of the relay. Am I right in thinking this is probably the case?
Capacitors C579-584 inclusive have been changed (I already had some in stock so changed them anyway), and I'm about to change out C576 (this one looks very "fat" in its sleeve so I have some on order). I guess I'm going to slowly re-cap the entire machine regardless, but I'd like to at least have it working whilst I'm doing this, so any ideas for what else I'm missing?
So far I've checked all resistors especially fusible ones, and all are well within range. All circuits appear to be continuous where they should be, eliminating broken tracks/bad solder joints etc, but any dodgy looking solder joints have been re-soldered anyway. I haven't pulled and tested any transistors yet, but that'll be my next job if nobody has any other suggestions.
Anything else for me to check chaps? I bet I've missed something really obvious... :scratch2:
