LC-PSU- Replaced-Caps- goes TICK TICK TICK

[uniserver]

i replaced all the cap's, little of a pain in the butt,

they were in-fact all leaking.

except for the 16v 47, but i replaced that one anyways,

none of the caps were bulging by the way...

plugged it in and turned it on checked voltages

+12 -good

+5 -good

-5 - good

i thought success!!!!!!!!!!!!

Then installed the psu into the LC, and then it just went tick tick tick

pulled it back out and checked the Voltages again

none of the voltages were good, they were 1.3v on the 12v

and like .3v on the +5v

so i am not sure what is going on here... i checked the Bridge and the big cap, it sits at 160v so i know atleast the high side is working

the only thing left is the transformer, Can bad caps melt the wires in a transformer, then making it internally short?

or could this be transistor or voltage regulator issue?

thanks for any help.

 

[uniserver]

i found this on another forum, this is getting a little out of my understanding.

====================================================>

22.10) Power-on tick-tick-tick or click-click-click but no other action

A variety of power supply or startup problems can result in this or

similar behavior. Possibilities include:

* Lack of startup horizontal drive - see the section: "Startup problems - nothing happens, click, or tick-tick-tick sound". The main regulator is

cycling on overvoltage due to lack of load.

* Excessive load or faulty power supply cycling on its overcurrent

protection circuit.

* High voltage shutdown, or some other system detecting an out of regulation

condition. However, in this case, there should be some indication that the

deflection and HV is attempting to come up - momentary whine, static on the

screen, etc.

* A dried up main filter capacitor or other filter capacitor in the low

voltage power supply that is producing an out-of-regulation condition

until it warms up. A bad filter capacitor on the output of a series

regulator may result in excessive voltage and subsequent shutdown.

* A problem with the microcontroller, relay or its driver, or standby

power supply.

One possible test would be to vary the line voltage and observe the

set's behavior. It may work fine at one extreme (usually low) or the

other. This might give clues as to what is wrong.

 

[James1095]

Tick-tick-tick means the power supply is starting up, detecting a fault and shutting down, then repeating the cycle. Do you have another LC to try it in to see if it works? You may have a short somewhere on the motherboard. Also double check to make sure you didn't create a solder bridge, miss a solder joint or crack an existing one that was sketchy. I've never seen a transformer fail in a switchmode PSU. Did you wash off all the leaked electrolyte? It's conductive and corrosive. I use a toothbrush and warm soapy water, followed by a good drying, either compressed air followed by a hair dryer or just let it sit out for a couple of days in a warm room.

Note that most computer power supplies will not operate correctly without some sort of minimum load on at least the primary (usually 5V) output. Automotive light bulbs make good test loads for the +12 and +5V outputs since they will also give a visual indication.

 

[uniserver]

it was OCT 23rd when I replaced the caps, tried it, it worked, then installed it and it started ticking again.

Tonight I gave it another try , Took it apart looked for solder bridges, didn't see any, however I didn't clean off any of the leaked crud from the old caps last time

cleaned it off with some soap and water, dried it off, put it back together.

Installed it.

For the moment it's working!

machine is powered up

I'll try it tomorrow, see if it still works

 

[James1095]

The leaked electrolyte is conductive. I'm not surprised the PSU was shutting down with that all over the board.