Protek Power Supply Problems

[Bruce_Mowbray]

I have a Protek model 60-0189-01 low voltage power supply for my CNC milling machine that is giving me problems. This PS provides both 12 and 5 volts for the machine's control system. While running the machine, the control went into alarm and the control shut down in a safe manner. After restarting the machine, the control would not power up and there was a faint clicking sound (about 4-5 Hz) coming from the Protek low voltage supply. The diagnostic LED indicator for the 5 volt line did not light and the control did not power up.

Here comes the diagnoses and repair,

I removed the power supply from the machine and powered it (the power supply) up on the bench. I tested the output and got 12 volts where it should be but the 5 volt taps were fluctuating between 3.5 and 4.8 volts. The non even 4-5 Hz clicking sound was still audible but not quite as loud. After letting the power supply run for a few minutes, the clicking sound went away. The 5 volt taps were now producing 5 volts. I powered it down, let it sit for a few seconds and powered it back up. The clicking sound returned and the voltage was again fluctuating. I did this numerous times with the same results. With a paper stethoscope, I narrowed down the clicking sound was being produced by the transformer (see picture with arrow pointing to the transformer in question)

Two questions.

1) Does the clicking sound coming from the transformer indicate a problem with this transformer or does the clicking sound point to another bad component?

2) How does one identify and match the transformer so as to find a replacement.

Thanks for your time on this.

Be gentle. I'm new at this stuff.

Bruce

[kc8adu]

Re: Protek Power Supply Problems

replace ALL lytics.
had 2 of those in here that all those peace vent caps were very high esr.
used panasonic fm to replace.

[jetadm123]

Re: Protek Power Supply Problems

I have a Protek model 60-0189-01 low voltage power supply for my CNC milling machine that is giving me problems. This PS provides both 12 and 5 volts for the machine's control system. While running the machine, the control went into alarm and the control shut down in a safe manner. After restarting the machine, the control would not power up and there was a faint clicking sound (about 4-5 Hz) coming from the Protek low voltage supply. The diagnostic LED indicator for the 5 volt line did not light and the control did not power up.

Here comes the diagnoses and repair,

I removed the power supply from the machine and powered it (the power supply) up on the bench. I tested the output and got 12 volts where it should be but the 5 volt taps were fluctuating between 3.5 and 4.8 volts. The non even 4-5 Hz clicking sound was still audible but not quite as loud. After letting the power supply run for a few minutes, the clicking sound went away. The 5 volt taps were now producing 5 volts. I powered it down, let it sit for a few seconds and powered it back up. The clicking sound returned and the voltage was again fluctuating. I did this numerous times with the same results. With a paper stethoscope, I narrowed down the clicking sound was being produced by the transformer (see picture with arrow pointing to the transformer in question)

Two questions.

1) Does the clicking sound coming from the transformer indicate a problem with this transformer or does the clicking sound point to another bad component?

2) How does one identify and match the transformer so as to find a replacement.

Thanks for your time on this.

Be gentle. I'm new at this stuff.

Bruce

The clicking sound you hear is the power supply trying to start up. What's unusual is the that you're getting a solid 12V. Usually, it's all or nothing. I'll venture a guess and say that maybe the 12V is not part of the switching power supply circuit, while the 5V is. Since the supply is trying to start and eventually suceeds, there is a chance of a capacitor problem. Usually, there is a startup cap that supplies initial voltage to get the supply started. It may be the small cap, C14, maybe 22uf or 47uf? You can try changing this and see what happens. I know your inclination is to head to Radio Shack to purchase the cap, but you must use a low-esr cap like Pansonic FM or FC series caps. Hopefully, you have some caps around that you can use for "testing" purposes. If that solves the problem, then replace ALL the caps.

The transformer is usually custom wound to the designer's specs, which means that when the board fails, the entire board is replaced and not individual components. In other words, a replacement transformer would be pretty difficult to find.

[Bruce_Mowbray]

Re: Protek Power Supply Problems

Thanks to both.

I will start by replacing the caps.
Would the clicking sounds come from the transformer even though the problem is with the capacitors? Also, will using the low esr caps have any effect on the output even though the original ones were general purpose caps (according to the oem company)? Should I replace all of the caps with low esr ones before testing the unit?

Like I said, I'm new at this...but I'm learning.

Thanks again

Brufec