Hello Folks,
I found a BA-2000 at a thrift store and was trying to restore it. I swapped all fuse resistors, relays, and caps.
It took me a month to do all this. I was excited about finally using it with my JBL's but when I tried to adjust the bias, C37 on F-2661 blew open.
My Mistake was that I accidentally connected the current meter probe b/w the blue 07 (L-CH, connected to the board) and red wire that goes to 06 (unplugged). Negative terminal to Blue wire (connected to PCB F-2629) and positive terminal to the RED wire (06 unplugged). This caused C37 to blow up in pieces. I looked at the SM and realized my mistake immediately.
I have a cutoff switch I built to use my feet to cut power and the moment it blew up I cut the power.
I am unsure how much damage this has caused down the line but the output transistor looks fine on a silicone tester. I might pull them out and test them again.
The issue is that my bias does not move when switching VR-01 or VR-02 it sits around 9.01 mA
I have 8Ohm loads on the output
The main volume is set to half the max.
In the SM it says Max but because of that C37 blowing up in my face, I am a little hesitant to turn the volume all the way up.
I am using a thermal camera and all the temperatures look fine.
Q1: Does the main volume need to be at the max?
Q2: Where should I start looking to resolve the issue ?
Q3: I changed the VR01/02 to 25 turn trim pots maybe I need to move them more to see and change in bias current but is there any way I can test to see if the bias is even moving before I crank the main volume to the max?
I found a BA-2000 at a thrift store and was trying to restore it. I swapped all fuse resistors, relays, and caps.
It took me a month to do all this. I was excited about finally using it with my JBL's but when I tried to adjust the bias, C37 on F-2661 blew open.
My Mistake was that I accidentally connected the current meter probe b/w the blue 07 (L-CH, connected to the board) and red wire that goes to 06 (unplugged). Negative terminal to Blue wire (connected to PCB F-2629) and positive terminal to the RED wire (06 unplugged). This caused C37 to blow up in pieces. I looked at the SM and realized my mistake immediately.
I have a cutoff switch I built to use my feet to cut power and the moment it blew up I cut the power.
I am unsure how much damage this has caused down the line but the output transistor looks fine on a silicone tester. I might pull them out and test them again.
The issue is that my bias does not move when switching VR-01 or VR-02 it sits around 9.01 mA
I have 8Ohm loads on the output
The main volume is set to half the max.
In the SM it says Max but because of that C37 blowing up in my face, I am a little hesitant to turn the volume all the way up.
I am using a thermal camera and all the temperatures look fine.
Q1: Does the main volume need to be at the max?
Q2: Where should I start looking to resolve the issue ?
Q3: I changed the VR01/02 to 25 turn trim pots maybe I need to move them more to see and change in bias current but is there any way I can test to see if the bias is even moving before I crank the main volume to the max?
