earthsled
Well-known member
Hi folks!
I'm working on an original Gates Sta-Level compressor. I believe the PT might be fried, but I wanted a sanity check before going down the road of replacement.
This unit was powered on by the engineers at the studio for testing. Unfortunately, they didn't notice the rectifier tube had broken glass. When powered up, the engineers reported a "burning smell" and that the unit was not passing signal.
Now that I have the Sta-Level on my bench, I found that there was an over-rated mains fuse installed. It had a 3A slow-blow instead of the 2A fuse specified in the manual.
Fearing the worst I removed all the tubes and gave it about 50V AC from my Variac. At this voltage, the unit was drawing about 1.25A. I didn't increase the voltage past 50V. After a few minutes, the PT started to get warm. Things are NOT looking good so far!
After powering the unit down, I took some resistance measurements from the PT and the choke. Here are my results:
Primary: 10 ohms
High Voltage Secondary: 300 ohms
5V Heaters: 0.3 ohms
6.3V Heaters: 0.2 ohms
Choke: 400 ohms
My best guess is the choke survived, but let me know if the resistance seems high to anyone. Also, I wanted to verify that 1.25A is an unusually high current draw for this PT without any tubes installed. Again, I suspect the PT is gone, but I didn't want to overlook anything.
Thanks in advance for your help!
I'm working on an original Gates Sta-Level compressor. I believe the PT might be fried, but I wanted a sanity check before going down the road of replacement.
This unit was powered on by the engineers at the studio for testing. Unfortunately, they didn't notice the rectifier tube had broken glass. When powered up, the engineers reported a "burning smell" and that the unit was not passing signal.
Now that I have the Sta-Level on my bench, I found that there was an over-rated mains fuse installed. It had a 3A slow-blow instead of the 2A fuse specified in the manual.
Fearing the worst I removed all the tubes and gave it about 50V AC from my Variac. At this voltage, the unit was drawing about 1.25A. I didn't increase the voltage past 50V. After a few minutes, the PT started to get warm. Things are NOT looking good so far!
After powering the unit down, I took some resistance measurements from the PT and the choke. Here are my results:
Primary: 10 ohms
High Voltage Secondary: 300 ohms
5V Heaters: 0.3 ohms
6.3V Heaters: 0.2 ohms
Choke: 400 ohms
My best guess is the choke survived, but let me know if the resistance seems high to anyone. Also, I wanted to verify that 1.25A is an unusually high current draw for this PT without any tubes installed. Again, I suspect the PT is gone, but I didn't want to overlook anything.
Thanks in advance for your help!