04-07-2014, 06:12 PM
Signal strength is not a problem - there are a few nearby FM transmitters that send the tuning meter over close to a full 5 on the 1 - 5 scale.
Well, the 700-T lives! But not without its anxious moments...
I tested all eight of my new ECG 162 transistors and selected the four with the closest beta to one another. I installed them...brought the receiver up slowly on the Variac...and had nothing in the left channel at first.
After supper, I thought I should check that B+ fuse for the left channel. Yup, it was open. It probably opened when the resistors smoked upon initial power-up, because of the shorted output transistor that has now been replaced, along with the other three.
I installed another fuse, and tried again. Now I had sound in left and right channels. Only the right was distorted pretty badly - at first. After a couple minutes, though, it straightened itself out and now sounds good.
Too bad the FM is in mono. Hopefully that will get resolved soon. But, hey, this is probably the first time in years that this receiver has been up and running.
I'll try lifting that 1 uF cap in the MPX board tomorrow, I won't have time to do any more to it tonight.
Oh, forgot to mention - that hum I was getting in the right channel at the input to the driver board with the signal tracer - it's gone.
No hum in left or right speakers.
Well, the 700-T lives! But not without its anxious moments...
I tested all eight of my new ECG 162 transistors and selected the four with the closest beta to one another. I installed them...brought the receiver up slowly on the Variac...and had nothing in the left channel at first.
After supper, I thought I should check that B+ fuse for the left channel. Yup, it was open. It probably opened when the resistors smoked upon initial power-up, because of the shorted output transistor that has now been replaced, along with the other three.
I installed another fuse, and tried again. Now I had sound in left and right channels. Only the right was distorted pretty badly - at first. After a couple minutes, though, it straightened itself out and now sounds good.
Too bad the FM is in mono. Hopefully that will get resolved soon. But, hey, this is probably the first time in years that this receiver has been up and running.
I'll try lifting that 1 uF cap in the MPX board tomorrow, I won't have time to do any more to it tonight.
Oh, forgot to mention - that hum I was getting in the right channel at the input to the driver board with the signal tracer - it's gone.
No hum in left or right speakers.
--
Ron Ramirez
Ferdinand IN
