[TechAssist] Re: Sony KV27FS100L

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
> <Wayne@xxxxxxxxxxxxxxxxxxxxx> 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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