This circuit board powers hollow cathode lamps for a analytical chemistry instrument. The lamps run at approximately 20 mA.
F1 intermittently blows and I can't figure out what is causing it. R36 and R37 were blown and replaced, (I did not identify why; I thought it was due to power fluctuations) but this didn't solve the issue. All the surrounding resistors, capacitors and diodes were removed and tested ok. Both transistors on either side of the fuse were replaced as well as a few of the diodes because of the surrounding discoloration I noticed, but the instrument works for a short time and then the fuse blows again. It's beginning to happen more frequently.
Does anything in the photo jump out to any of you experts or does anyone have an understanding of this board to help guide my troubleshooting? Thanks in advance.
F1 intermittently blows and I can't figure out what is causing it. R36 and R37 were blown and replaced, (I did not identify why; I thought it was due to power fluctuations) but this didn't solve the issue. All the surrounding resistors, capacitors and diodes were removed and tested ok. Both transistors on either side of the fuse were replaced as well as a few of the diodes because of the surrounding discoloration I noticed, but the instrument works for a short time and then the fuse blows again. It's beginning to happen more frequently.
Does anything in the photo jump out to any of you experts or does anyone have an understanding of this board to help guide my troubleshooting? Thanks in advance.
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