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Electronics => Repair => Topic started by: RyanG on April 21, 2017, 01:46:39 am

Title: LCD PSU
Post by: RyanG on April 21, 2017, 01:46:39 am

I have a PSU here that isn't putting out power. I checked the easy stuff and I am not getting anything on the secondary side of the T1 transformer, but I am reading no open circuits on the primary or secondary. The primary has a 2k-ish resistance. Primary side has ~350v. I attached the schematic that I found online. It also has an on/off pin on one of the connectors, so should I connect 5v to it?

Title: Re: LCD PSU
Post by: Jay_Diddy_B on April 21, 2017, 02:28:47 am

Ryan,

I have looked at the schematic. I think if you connect pin 1 (on/off)  to pin 6 (5V standby) on CNS1 the other rails should turn on.

In fact measure the voltage on pin 6 of CNS1 to pin 7 or 8 GND and see if the standby supply is working.

Regards,

Jay_Diddy_B

Title: Re: LCD PSU
Post by: RyanG on April 21, 2017, 03:16:00 am

I did check the standby and it is good at 5v. I will try connecting it to pin 1 when I get home from work. Thanks

Title: Re: LCD PSU
Post by: RyanG on April 21, 2017, 05:47:12 am

Connecting pin1 to 5v turned everything on. I had a very terrible 24v output bouncing between 23v and 26v. I changed out the EC2 cap and it was a smooth 24v after that.