Problem with the filament circuit. Q301 transistor will short out when making an exposure at 500MA.
Initial service call was no exposure on small spot. Found SS filiment open, and Q301 shorted. Replaced Q301 with a NTE243 which was the original one that shorted.
Replaced Q301, used a lamp for test purposes, transistor failed with in 15 minutes while unit was in standby. Replaced it thinking I had installed a defective one.
I was able to boast the filaments up to 400MA selection at which time Q301 shorted. Thinking that the lamp filament might require more current, I than installed the x-ray tube. Monitored filament circuit closely and proceeded to calibrate. Calibrated 25, 50, and 100MA SS, no problem. Than proceeded to calibrate LS 200, 300, 400MA no problem, Q301 failed on the first exposure at 500MA, Measured 490MA, exposure was terminated by the timer, KV on scope was okay. Circuit seem to be operating okay.
Has anyone seen this problem? Any ideas on what could cause this?
I'm curious about the actual filament current, and not the exposure current. It sounds like the filament current may be exceeding 5.5 Amps, especially if the Small filament opened.
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Paul Collins
Picker BGX625 Generator Problem
October 10, 2008 04:50
Problem with the filament circuit. Q301 transistor will short out when making an exposure at 500MA.
Initial service call was no exposure on small spot. Found SS filiment open, and Q301 shorted. Replaced Q301 with a NTE243 which was the original one that shorted.
Replaced Q301, used a lamp for test purposes, transistor failed with in 15 minutes while unit was in standby. Replaced it thinking I had installed a defective one.
I was able to boast the filaments up to 400MA selection at which time Q301 shorted. Thinking that the lamp filament might require more current, I than installed the x-ray tube. Monitored filament circuit closely and proceeded to calibrate. Calibrated 25, 50, and 100MA SS, no problem. Than proceeded to calibrate LS 200, 300, 400MA no problem, Q301 failed on the first exposure at 500MA, Measured 490MA, exposure was terminated by the timer, KV on scope was okay. Circuit seem to be operating okay.
Has anyone seen this problem? Any ideas on what could cause this?
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Brian Tunell
Re: Picker BGX625 Generator Problem
July 08, 2010 02:46
Have you solved this problem?
I'm curious about the actual filament current, and not the exposure current. It sounds like the filament current may be exceeding 5.5 Amps, especially if the Small filament opened.
to rate and post a comment