NEC JC-1571 with raising B+ & shutdown

R

RobertDubord

Guest
Monitor came in with no pix symptom. Collector of HOT had 150vdc,
1200ppv with reduced frequency and a squashed waveform.

Changed Q5G1 (2SJ306) wich was short and pix came back with always
increasing brightness until shutdown.

Also changed Q2001 (A1L4M)=nte2360 witch was open but the problem
remains the same.

Flyback rings OK with R5U1 lifted and HOT tests good.
 
If the 2SJ Was Shorted, it usually Damages or Weakens the HOT. So to be
sure, I always Replace both of them.

I dont see how the HOT would effect Brightness, but it may cause the
Shutdown problem. Resolder the FBT Pins , and there is sometimes bad Solder
anywhere on the JC-15 Series Monitors From the factory.



"RobertDubord" <rdubord@globetrotter.qc.ca> wrote in message
news:_oe6b.1536$C92.1453@charlie.risq.qc.ca...
Monitor came in with no pix symptom. Collector of HOT had 150vdc,
1200ppv with reduced frequency and a squashed waveform.

Changed Q5G1 (2SJ306) wich was short and pix came back with always
increasing brightness until shutdown.

Also changed Q2001 (A1L4M)=nte2360 witch was open but the problem
remains the same.

Flyback rings OK with R5U1 lifted and HOT tests good.
Click to expand...
 
Wonderful!

Subbed HOT 2SC5129 with 2SC5048 and B+ regulation became stable
even though the 5129 tested good.

Thanks techforce and the group.

"techforce" <techforce@~nospam!juno.com> a écrit dans le message news:
K_l6b.22079$2Y6.8380519@news2.news.adelphia.net...
If the 2SJ Was Shorted, it usually Damages or Weakens the HOT. So to be
sure, I always Replace both of them.

I dont see how the HOT would effect Brightness, but it may cause the
Shutdown problem. Resolder the FBT Pins , and there is sometimes bad
Solder
anywhere on the JC-15 Series Monitors From the factory.



"RobertDubord" <rdubord@globetrotter.qc.ca> wrote in message
news:_oe6b.1536$C92.1453@charlie.risq.qc.ca...
Monitor came in with no pix symptom. Collector of HOT had 150vdc,
1200ppv with reduced frequency and a squashed waveform.

Changed Q5G1 (2SJ306) wich was short and pix came back with always
increasing brightness until shutdown.

Also changed Q2001 (A1L4M)=nte2360 witch was open but the problem
remains the same.

Flyback rings OK with R5U1 lifted and HOT tests good.
Click to expand...
 
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