Hello gang,
Receiver is from later production and in really clean and nice condition.
I have performed modifications with the kit purchased from Tube Tycoon. Later I found some people suggesting against him but too late now. All parts replacement went well. I was testing all parts removed and really did not find any that drifted further then 15-20 % off spec values. Tubes were tested by local vintage stereo shop with almost excellent results except for one 12AX7 tested 70/30 which they told me is not going to cause any issues for now. I cleaned all controls and slowly powered receiver with borrowed Variac and everything worked.
Several concerns:
1. Aluminum can capacitor next to power transformer gets warm before transformer even start to warm-up.
2. Cardboard capacitor underneath the chassis has a faint burnt transformer smell.
3. Receiver has great bottom end sound but seems to lack highs in flat position of the treble pot.
3.The middle tube on the MPX board was flashing bright and then go dim on power-up. I had tubes rearranged since and it is not doing it now. Possibly, it was the one that tested weak. It is in the Phono section for now.
4. Tuner is not very clean in stereo. Switching to mono cleans the sound.
I love the sound of this receiver and want to improve it's abilities and could use guidance.
What are my next steps?
Thanks
Dmitriy
Receiver is from later production and in really clean and nice condition.
I have performed modifications with the kit purchased from Tube Tycoon. Later I found some people suggesting against him but too late now. All parts replacement went well. I was testing all parts removed and really did not find any that drifted further then 15-20 % off spec values. Tubes were tested by local vintage stereo shop with almost excellent results except for one 12AX7 tested 70/30 which they told me is not going to cause any issues for now. I cleaned all controls and slowly powered receiver with borrowed Variac and everything worked.
Several concerns:
1. Aluminum can capacitor next to power transformer gets warm before transformer even start to warm-up.
2. Cardboard capacitor underneath the chassis has a faint burnt transformer smell.
3. Receiver has great bottom end sound but seems to lack highs in flat position of the treble pot.
3.The middle tube on the MPX board was flashing bright and then go dim on power-up. I had tubes rearranged since and it is not doing it now. Possibly, it was the one that tested weak. It is in the Phono section for now.
4. Tuner is not very clean in stereo. Switching to mono cleans the sound.
I love the sound of this receiver and want to improve it's abilities and could use guidance.
What are my next steps?
Thanks
Dmitriy