Dear All,
After a long time away from this I'm planning to recap and renovate the amplifier from my AMI Continental (1). That is a R-2777 Basic Amplifier with L-2156 Add-on Control amplifier. I have a capacitor kit, the schematics and a manual.
This is not my first amplifier rebuild. Back at the end of the last century I re-capped a R-22 amplifier from my AMI Model B and also the amplifier from my Wurlitzer Lyric E. Both of these were much simpler and the technique was also simpler where I just took great care to substitute the new for the old. There were no adjustments and if you did it correctly you plug it in at the end and it works which is indeed what happened.
This time around there is more complexity and there are adjustments. to be made. Firstly I would be happy to hear what people who do this use as a working environment. I have read about using an incandescent lamp in the mains supply circuit in order to be aware that the amplifier under test is not drawing high current. I will be using a step down transformer. I need to ensure that the output is driving into a suitable load (speaker). Are there any other similar requirements?
Am I correct in saying that when I come to power up the amp I do so without any of the valves in their sockets? What about the rectifier?
The schematic shows that the dc levels are measured without any signal input. Are all measured without any valves or do you add in valves as you progress through the circuit?
When you have all the dc levels correct you apply a 1khz signal. What voltage?
Have the valves all been refitted by this stage? Am I measuring the voltage from the pins beneath the chassis? Or am I indeed adding them as I measure through the circuit.
If you feel I'm planning on doing this wrongly please say so. Any help will be gratefully received.
Finally I should say that I am aware of the hazards of higher voltage circuits. I plan to use only one hand when measuring the voltages.
Best Regards,
Doug