Sounds like you are on the right track. The filament load current is higher @ turn on than when it's warmed up, so the SMPS may be going into an overcurrent shutdown mode. Maybe bad cap or I have also seen the SMPS output FET-to-ground resistor change value slightly, which trips the overcurrent sense input on the controller ic. Jerry Christians Electronic Service ----- Original Message ----- From: "Phil Bader" <philbad@xxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Friday, November 16, 2001 5:39 PM Subject: [TechAssist] [Fwd: update.Re: NEC P7701 Multisync 70 relay may chatter at turn on,no display.] | | | | -------- Original Message -------- | Subject: update.Re: NEC P7701 Multisync 70 relay may chatter at turn | on,no display. | Date: Fri, 16 Nov 2001 17:16:44 -0500 | From: Phil Bader <philbad@xxxxxxxxxx> | Organization: Jan Phyl TV Inc. Winter Haven, Fl. Estab. 1976 | To: Electronic Hardware Repair <ELREPAIR-L@xxxxxxxxxxxxxxxxxxxx> | References: <3BF19BB7.ADB2C584@xxxxxxxxxx> | | After much testing,Iunplugged CRT socket.Behold!Unit clicked once,HV | came up and stayed.I replaced the rectifier and cap in this 6 volt line, | D113, C122 (1000mfd). No help. I replugged CRT board back into CRT and | unsoldered the actual CRT filiment pin (high side, +6V) and monitor will | stay up and run.If, while it is on I jumper the fil pin, CRT will show | good display.So, just unsoldering the CRT fil. pin does the trick.I | ohmed the CRT fil. pins, no dead shorts,Fil volts no load at 8VDC, with | load, 6VDC. I am stumped. It's like the CRT is loading this source and | shutting down the SMPS. Ideas??? | | Phil Bader wrote: | > | > Customer said it would "click,click,click".Sometimes it comes up with | > good display here in shop. Other times, push power,hear relay clicking | > erratically, or so rapidly,may almost vibrate.No HV, no display.-TIA, | > Phil | ***************************************** | Help make your TechAssist online repair tips | database better! Submit your fixes here: | http://www.circuitwork.com/techassist/tip/#tips | ***************************************** | To UNSUBSCRIBE write to: | techassist-request@xxxxxxxxxxxxx | with unsubscribe in the subject line. | ***************************************** Help make your TechAssist online repair tips database better! Submit your fixes here: http://www.circuitwork.com/techassist/tip/#tips ***************************************** To UNSUBSCRIBE write to: techassist-request@xxxxxxxxxxxxx with unsubscribe in the subject line.