[TechAssist] Re: Sony KV27FS100L
- From: Paul <dntwntv@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Fri, 30 Sep 2005 13:48:17 -0700 (PDT)
The pulses are about 4 or 5 hundred p/p. I scoped it at the collector of the
HOT, but with only 47v I didn't expect much else. The slow start circuitry that
you mention seems to fit what is going on.This set is Mar. 2004. I have been
checking the scan derived voltages to see if something could be the cause
there, but haven't found anything yet. The markings on the chassis are not
helping either. I have found mismarked components and the 6's,8's and 9's are
hard to tell the difference. Then to make matters worse the customer is moving
and wants the TV today. Love this business!
Paul
Wayne Vanaman <Wayne@xxxxxxxxxxxxxxxxxxxxx> wrote:
What do the horizontal pulses look like? If you can't probe the
collector of the horizontal output transistor probe a secondary.
I haven't paid attention to the actual startup of these, but there are
several sets now that are using a "slow start" in the horizontal
section. They will typically run the output transistor at 20Khz or so
for a couple of seconds then drop down to 15K and the set comes up at
full power. It uses the start up time to determine if all supplies are
coming up. I don't see the audio supply being monitored anywhere.
Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl. 32506-3310
Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com
850-456-5995 voice
850-458-6369 fax
Paul wrote:
> I don't think the vertical I/C that I replaced was bad. The problem
> seems to be that the B+ never gets up to 135v. It makes about 47v
> then shuts down and goes into standby. I found a dual diode that was
> shorted in the secondary but it supplies the audio amp and removing
> it did not make any difference in the low B+ problem. Unless the
> secondary needs an exact load in order to run, I am at a loss to
> know what is going on. Paul Wayne Vanaman
> wrote: I have seen a number of sets
> that, when the vertical IC fails it takes out the video processor.
> Check for vertical drive out of the processor. Pins 28 and 29. These
> are complimentary sawtooth waveforms, about 1.2v pk-pk.
>
> Wayne Vanaman Omega Electronics 6904 W Fairfield Dr Pensacola, Fl.
> 32506-3310
>
> Wayne@xxxxxxxxxxxxxxxxxxxxx WWW.PensacolaTVRepair.Com
>
> 850-456-5995 voice 850-458-6369 fax
>
>
> Leonard Caillouet wrote:
>
>> Four blinks can be either vertical or horizontal or something else
>> that causes the vertical output to not work.
>>
>> Leonard Caillouet Service Manager Electronics World Gainesville, FL
>>
>>
>> ----- Original Message ----- From: "Paul" To: Sent: Thursday,
>> September 29, 2005 8:39 PM Subject: [TechAssist] Sony KV27FS100L
>>
>>
>> How reliable are blink codes? This set is becoming more of a
>> problem than I first thought. The blink code is four, indicating a
>> problem in the vertical circuit, as I suspected before getting the
>> service manual. I replaced the vertical I/C as the most likely
>> cause per the self diagnostics. Problem remains, that being the set
>> tries to start but never makes enough B+ and goes into stand by. I
>> removed the HOT and replaced both switching mosfets. Nothing has
>> changed. I have checked the lytics in that circuit, and supply
>> resistors. Nothing shorted or low to ground on the B+ line.Haven't
>> found anything bad yet. When I took the back off and saw that the
>> chassis was the one that has bad tact switches I headed there
>> first. Anyone familiar with this chassis and this problem? Paul
>>
>>
>> Paul ,B Central TV&Video 911W Grand Ave Grover Beach Ca.
>> (805)481-8084
>>
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> Paul ,B Central TV&Video 911W Grand Ave Grover Beach Ca.
> (805)481-8084
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Paul ,B
Central TV&Video
911W Grand Ave
Grover Beach Ca.
(805)481-8084
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