EBME Forums Forums Maintenance Technical Assistance Benette seHFQ-600

Benette HFQ- 600SE. The machine produce low quality x-ray, exposure terminate before the preset mAs reached. At first we suspected stored energy battery, After battery is changed the output is still low, then we suspected HT cable,after changing the cable there was no change in quality.the charging voltage for the batteries was set withing specified rage of +_ 240-260V
the filament voltage was also set to 36V. We tried to calibrate the machine but still no difference, Fuse 1 and R32 keeps blowing continuously each time an exposure is taken @`calibration mode. So gurus in the house what else can we do to solve the of low x-ray quality? Thanks
Engr. Oyekunle

Benette HFQ- 600SE. The machine produce low quality x-ray, exposure terminate before the preset mAs reached. At first we suspected stored energy battery, After battery is changed the output is still low, then we suspected HT cable,after changing the cable there was no change in quality.the charging voltage for the batteries was set withing specified rage of +_ 240-260V
the filament voltage was also set to 36V. We tried to calibrate the machine but still no difference, Fuse 1 and R32 keeps blowing continuously each time an exposure is taken @`calibration mode. So gurus in the house what else can we do to solve the of low x-ray quality? Thanks
Engr. Oyekunle

there is a simple solution that i am getting is problem in your x -ray tube.you have to change it or repair it...

Engr: ishtiaque

Low quality output (or "soft" x-rays) often indicates a tube which may have lost some of its vacuum. But that sort of thing is usually only found in very old tubes.

But when you say "low quality x-ray" ... what exactly are you getting in radiographic terms? "Light" or transparent radiographs?

Does the problem appear at low (as well as high) factors?

What is Fuse 1 protecting? Which circuit contains Fuse 1 and R32?

Does the tube have two filaments (and does it work on the "other" one)? Have you tried continuity checks of the filament(s)?

More information required!

The tube is light when viewed with florescent screen. The max mA of the machine is 300mA & the minimum is 25ma. When you expose At low factor say 75mA, when you pre-set 3.7mAs then after exposure the display console dispayed 3.7mAs but when the 37.5mAs is preset you hardly get 8mAs displayed after exposure.
When you expose at high factor say 300mA, when you pre-set 15mAs, after exposure display console displayed 15mA but the radiation is light. when 150mAs is pre-set the maximum mAs displayed is 14mAs, the output still weak and you feel the loading effect of the machine.
Sometimes when the mA code is altered so that to get exact value of mAs pre-set or at least something closer, fuse 1 or r32 of A14 cut out. A14 is responsible for charging of back up batteries SE3 & SE4. the batteries @ Se3 get charged through R32 and F1

dear oyekunle...
did you sea any oil leakage from the the tube...

No trace of oil leakage. F1 is rated 1.5A, each time exposure is taken the fuse F1 of A14 blown out.F1 charges positive sets of batteries (+205V) . When exposure is taken the back-up contactor K2 connects the charged batteries through IGBT driver to cathode high tension side.

i faced the same problem at the time of exposure my fuse and IGBT both shorted and blown ...then i checked the complete circuitry there was no any problem... but as i replaced the tube problem has solved.......

Can you kindly assist with the detailed circuit diagrams of each board of Benette HFQ-600SE, mine is block diagram.
I would be glad also if you can help with manual of philip practix 105. thanks
Oyekunle

I have changed the old tube to new one, but yet KVP? error still shows and the fuse cut again. KVP? means that there is problem with anode circiut or Anode high tension transformer. The four IGBT were tested to be ok.