[TechAssist] Re: CTC203 won't start and click
- From: Bil Green <tv.vcrrepair@xxxxxxxxxxx>
- To: al m <techassist@xxxxxxxxxxxxx>
- Date: Tue, 21 Jan 2003 18:53:20 -0800
> would turning down the screen voltage stop the burning of the CRT?
It sure would. Pulling the CRT board off will too.
--
Best regards,
Bil Green
2001 TV VCR
Mammoth Lakes, California
760-934-2001 mailto:tv.vcrrepair@xxxxxxxxxxx
Tuesday, January 21, 2003, 6:18:02 PM, you wote:
am> Now this might seem like a stupid question but would turning down the screen
am> voltage stop the burning of the CRT?
am> al marquardt
am> ampm@xxxxxxx
am> ----- Original Message -----
am> From: "Jeff Dougherty" <support@xxxxxxxxxxxxxxxxxx>
am> To: <techassist@xxxxxxxxxxxxx>
am> Sent: Tuesday, January 21, 2003 4:24 PM
am> Subject: [TechAssist] Re: CTC203 won't start and click
>>
>> Yes, I have seen it in 90 sets, at least.
>> I never left it on long enough to burn the phosphors.
>> support@xxxxxxxxxxxxxxxxxx
>> FAX 717-564-4952
>> Jeff Dougherty
>> Intrepid Video & Electronics Be careful of your thoughts.
>> 501 Luther Rd They may become your words
>> Harrisburg, PA 17111 any moment.
>> 717-909-8844
>> VCR tips, electronics info & general interest.
>> www.intrepid-video.com www.tech-repair.net
>> www.thetoolcaddy.com www.9-11-2001tragedy.com
>> ***********************************************************************
>>
>> ----- Original Message -----
>> From: "Bil Green" <tv.vcrrepair@xxxxxxxxxxx>
>> To: "Joe Batchelor" <techassist@xxxxxxxxxxxxx>
>> Sent: Monday, January 20, 2003 8:21 AM
>> Subject: [TechAssist] Re: CTC203 won't start and click
>>
>>
>>
>> I have been pulling the yoke plug on direct view TVs on ocassion for
>> many years and don't recall seeing a bright dot on sets made in the
>> 1980 or 90s. Have you seen this?
>>
>> When talking to tech support I have not been critised for doing this.
>> At one point GE recommended this proceedure to limit the HV and
>> reduce the chance of blowing a HOT while testing.
>>
>> In the 1960s and 70s this was definately a no-no.
>>
>>
>> --
>> Best regards,
>>
>> Bil Green
>> 2001 TV VCR
>> Mammoth Lakes, California
>> 760-934-2001 mailto:tv.vcrrepair@xxxxxxxxxxx
>>
>>
>> Sunday, January 19, 2003, 2:58:00 PM, you wote:
>>
>>
>> >>One of the first things to do is simply pull the yoke plug . . . .
>>
>> JB> I would never tell anyone to do this.
>> JB> It could burn a spot on the CRT if high voltage does come up.
>>
>> JB> In the good old days they had a jumper or interlock that would
>> JB> break the B+ when the yoke was unplugged.
>>
>> JB> I would remove the CRT socket before trying to run a set without
>> JB> the yoke plugged in.
>>
>> JB> Joe Batchelor CET TX-80
>>
>> JB> 1/13/03 10:44:42 AM, Bil Green <tv.vcrrepair@xxxxxxxxxxx> wrote:
>> >>Hi Pete,
>> >>
>> >>If you have way too much current flowing through the flyback then the
>> >>problem should be in the collector circuit of the HOT (including the
>> >>flyback of course). I don't see how the Gemstar module could cause too
>> >>much current in the collector circuit of the HOT unless the horiz freq
>> >>is way off.
>> >>
>> >>One of the first things to do is simply pull the yoke plug (much easier
>> >>than changing the yoke or troubleshooting the whole circuit).
>> >>
>> >>With the yoke out of the circuit the HV will be much lower than normal
>> >>(may even work if the yoke circuit was the problem).
>> >>
>> >>Good to scope the collector of the HOT also. Make sure your scope can
>> >>handle at least 200VAC and always set the 10x probe to 10X or the
>> >>~1500 or so volts will fry your scope. With the 100W lamp in series
>> >>with the ~130V B+ you may get a reading on the collector. Somewhere
>> >>around 1000VPP (without the light bulb), very clean pulses, about 12us
>> >>wide, ~55us between pulses.
>> >>
>> >>You replaced the flyback, yoke, etc? I almost always check to see
>> >>which parts are actually bad first. Whenever I guess, I'm almost always
>> >>wrong. Expensive to replace a few large parts. Pull the yoke, ring
>> >>test the flyback (or eliminate other possibilities first).
>> >>
>> >>You may want to put the original symptom back into this e-mail so
>> >>people know what the problem is. I forgot what you said.
>> >>
>> >>--
>> >>Best regards,
>> >>
>> >>Bil Green
>> >>2001 TV VCR
>> >>Mammoth Lakes, California
>> >>760-934-2001 mailto:tv.vcrrepair@xxxxxxxxxxx
>> >>
>> >>
>> >>Saturday, January 18, 2003, 5:53:06 AM, you wote:
>> >>
>> >>
>> >>
>> >>
>> >>P> Thanks Bil, that's what I get, to much current and no any raster, and
am> as
>> >>P> I wrote in my first post, I've replaced all those parts in the output
>> >>P> circuit. scoping the base drive signal on the HOT, seems to be on
>> >>P> frequency and value.
>> >>
>> >>P> Well..... this is an RCA 203 model chassis...
>> >>P> Do you think that the "GEmstar" module
>> >>P> could be the problem??
>> >>
>> >>
>> >>P> E-mail message
>> >>
>> >>P> Sender: techassist-bounce@xxxxxxxxxxxxx From:
am> tv.vcrrepair@xxxxxxxxxxx
>> >>P> (Bil=A0Green) Date: Wed, Jan 15, 2003, 4:19am (EST-3) To:
>> >>P> techassist@xxxxxxxxxxxxx (Pete)
>> >>P> Subject: [TechAssist] Re: CTC203 won't start and click Reply=A0to:
>> >>P> techassist@xxxxxxxxxxxxx
>> >>
>> >>P> Hi Pete,
>> >>P> When using a 100W lamp in series with the B+ to the flyback, it
am> should
>> >>P> not light up brightly. If it does you have too much current flowing.
>> >>P> If everything is OK you will get a raster (smaller than normal, but
am> good
>> >>P> enough to show that the all the circuits are working).
>> >>
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>>
>>
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