[TechAssist] Re: Sansui COM7200 tv/vcr

  • From: John at Main TV <maintv@xxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Fri, 06 Jun 2003 16:06:23 -0600

I am pasting the fix I posted for this model a few weeks ago.   BTW, the 
fly will not ring good in the circuit because of PCC transistor Q409 
even though the transistor is good.  John...........
This Sansui COM7200(made by Orion in 2002 - 27" combi) gave me a lot of
trouble.  The horizontal output transistor had B+ and (some) drive on
the base (1.6 volt p/p) but no HV.  The problem turned out to be the
horiz. drive transformer, Orion 0450190161.  I compared the new
transformer to the old one and the DC resistance was almost identical,
however the inductance reading on the primary of the old one was half
the new one (40mh compared to 72mh on new one).  The base signal on the
working set is 12v p/p. Thanks to Mark Goldspiel and Jerry Silverman for 
suggesting the transformer as the problem.
-- 

Paul wrote:
> I'm am trying to pin down the reason for no high voltage. This was made by 
> Emerson I believe. I do not have service lit. for this set. I have replaced 
> the HOP xstr. I have soldered the IHVT & driver transformers as well as other 
> associated circuitry. I have removed and rung the IHVT.  HOPxstr.has 130v on 
> collector.What I don,t have is a wave form of any significant size or shape 
> on HOP collector. So I disconnected the collector checked the wave form on 
> the base of the HOPxstr. Wave form is good.My logic was OK then, it has to be 
> in the secondary some place. But where? Well, I reasoned If I unsolder the 
> primary connect the ringer and unsolder one secondary at a time it should 
> show up. As I unsolder-ed each pin it finally rang good(went from4to41).Great 
> I said thats the leg that is bad. Wrong! I chased that circuit till I found a 
> place to disconnect every thing on it. No help. I continued to unsolder the 
> next couple of pins on the IHVT finally came to one that let the ringer
 go
>   back to 41. It was the ground.The question is where is my logic faulty? Am 
> I expecting to much from the ringer? Sorry for the rambling?    Paul     
> 
> 
> Paul ,B                                                                       
>                                        Central TV&Video                       
>                                                                               
>      Grover Beach Ca.
> 
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-- 
John Mielke
Main TV
Longmont,Co 80501
303 776 6955
303 776 0792  fax
maintv@xxxxxxxxxxx


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