Re: Stumped with a K7000

He probably means the big wirewound resistor.

RCade Resources wrote:
> Which one would that be now? I can check in a bit... got a part number
> handy?
>
> Thanks!
> Rob
>
> -----Original Message-----
> From: owner-rasterlist@vectorlist.org
> [mailto:owner-rasterlist@vectorlist.org] On Behalf Of John Robertson
> Sent: Saturday, April 03, 2010 12:41 PM
> To: rasterlist@vectorlist.org
> Subject: Re: RASTER: Stumped with a K7000
>
> RCade Resources wrote:
>
>> Hey guys,
>> OK, here's the deal...
>>
>> I have a 19K7901 that I received in non-working order. The previous owner
>> had capped it, replaced the flyback and HOT. Turns out the HOT was not
>> insulated, hence no workie. I replaced the HOT, and insulated it, and the
>> monitor worked fine for a while, with the exception of occasional flickers
>> (like the HV shutting down momentarily).
>>
>> Well, it decided it didn't like working here anymore and quit.
>>
>> I pulled the chassis and started testing it out. The HOT had died again,
>> and the voltage reg at IC4 appeared to be shorted. I'll skip a bunch of
>> boring details, but here's where I'm at now:
>>
>> Pulled IC4, and it is not shorted out of circuit. I ordered some to have
>>
> on
>
>> hand anyway, but I think this one is OK.
>>
>> If I power the chassis up on my bench, B+ only measures around 18VDC,
>>
> IIRC.
>
>> I have pulled the HOT and IC4 and powered the chassis without them. The
>>
> pad
>
>> for pin 1 of IC4 is still only getting around 24VDC. The left-hand side
>>
> (on
>
>> the schems) of R103 is getting 120-ish, though.
>>
>> I clipped the blue lead off R301/302 (the right-hand side on the schems),
>> and powered it up again. Now pin 1 where IC4 should be starts off around
>> 70VDC and slowly trickles up to 120-ish. Powering down, that pin slowly
>> trickles back down.
>>
>> On a whim, I replaced C55, C56, and C57, and reconnected the other end of
>> R301/302. Still only getting about 24VDC at the pad for pin 1 of IC4.
>>
>> Thoughts?
>>
>> Thanks,
>> Rob
>>
>>
>>
> Regulator pass resistor blown?
>
> John :-#)#
>
>

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Received on Sat Apr 3 16:02:53 2010