Good day to all !
I have a ZD-985 station. It suddenly went dead during normal use. I opened it up and found the PSU has died.
The PSU is exactly the same as the one on the ZD-915 station mentioned and pictured here:
https://www.badcaps.net/forum/showthread.php?t=78148
and here :
https://www.badcaps.net/forum/showthread.php?t=39651
I checked all the components that I could including the mosfet, rectifier , capacitors, optocouplers, diodes, fuse and all appear in good condition. So I ordered and replaced the switching IC (CQ1565RT). The (2200uf 25V) capacitors measured about 2100 uf capacitance and 0.something ohms ESR.
When I put in the new one the PSU came to life and so did the station but after a few seconds it died again with exact same symptoms.
I suspected the heating element which appears to be about 110Watt not 80 because at 18Vt it draws 6A. So I thought that maybe the heating element and pump drive the PSU too hard.
I again changed the switcher and again it came back to life. This time I disconnected the heating element and placed a 5A fuse between the +18V output and the vacuum pump. This time I noticed that after three short trigger pushes with the pump going on and off the PSU died again…
I have no idea what causes the IC to die like that. Also I have trouble finding a 18V PSU with enough current capacity (more than 8A) For the time being I have removed its transformer and feed 18V DC directly between the transformers grounded pin and the one going to the rectifier from my bench PSU and current consumption varies from 9A when the heating element and pump are on to 2A when heating element is in idle and pump is off.
Any ideas or suggestions ? THANK YOU !
I have a ZD-985 station. It suddenly went dead during normal use. I opened it up and found the PSU has died.
The PSU is exactly the same as the one on the ZD-915 station mentioned and pictured here:
https://www.badcaps.net/forum/showthread.php?t=78148
and here :
https://www.badcaps.net/forum/showthread.php?t=39651
I checked all the components that I could including the mosfet, rectifier , capacitors, optocouplers, diodes, fuse and all appear in good condition. So I ordered and replaced the switching IC (CQ1565RT). The (2200uf 25V) capacitors measured about 2100 uf capacitance and 0.something ohms ESR.
When I put in the new one the PSU came to life and so did the station but after a few seconds it died again with exact same symptoms.
I suspected the heating element which appears to be about 110Watt not 80 because at 18Vt it draws 6A. So I thought that maybe the heating element and pump drive the PSU too hard.
I again changed the switcher and again it came back to life. This time I disconnected the heating element and placed a 5A fuse between the +18V output and the vacuum pump. This time I noticed that after three short trigger pushes with the pump going on and off the PSU died again…
I have no idea what causes the IC to die like that. Also I have trouble finding a 18V PSU with enough current capacity (more than 8A) For the time being I have removed its transformer and feed 18V DC directly between the transformers grounded pin and the one going to the rectifier from my bench PSU and current consumption varies from 9A when the heating element and pump are on to 2A when heating element is in idle and pump is off.
Any ideas or suggestions ? THANK YOU !
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