[TechAssist] Re: [Fwd: update.Re: NEC P7701 Multisync 70 relay may chatter at turn on,no display.]
- From: Phil Bader <philbad@xxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 19 Nov 2001 22:14:38 -0500
After replacing all PS caps,and testing til blue in the face, as a
"test" I isolated the CRT fil pins from the 6 VDC source, inserted a
small 60 Hz 6.3 VAC filament transformer (primary wired to come on with
the power switch),mounted it far and away from any interaction with the
CRT magnetics (a tough feat),and it works beautiful. I know, I
know....But the main thing is a good usable 17" monitor without a
fortune in repair cost. It's been burning in for hours now. Don't anyone
scold me for my "short cut"! ;-)
Phil Bader wrote:
>
> -------- 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
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