Magnavox TV TP2770C101 ch 27B502 HV Problem

[Brad Petria]

Hi,

I have a Magnavox TV chassis 27B502-00AA in my shop. I replaced
the H.O.T. Q503 # 610597 (on device) which was shorted and the horiz. driver
Q500 BSN274 # 483513047931 which was bad. I checked the regulated
B+ which is 131.8V (130V is ideal). The HV measures 30KV when it should
be 27KV - 28KV. Note: It can't be due to 1.8V high B+ since math shows an
increase of about 400V (HV). I checked the FBT core and it isn't loose.
Did you have this experience and what was the cause?

Thanks in advance, Brad

Tip for your old computer (reduce discard pollution too):

If you can't sell your old computer, don't throw it away. Use it to backup
your software by transferring files/folders from your new computer or laptop
to it. I transferred my Windows folder and other stuff to my old computer
using "PC Link", which I downloaded from www.simtel.net (cool site).

http://www.simtel.net/pub/dl/52792.html (info or download)

 

[Asimov]

"Brad Petria" bravely wrote to "All" (22 Sep 03 16:54:00)
--- on the heady topic of "Magnavox TV TP2770C101 ch 27B502 HV Problem"

Check the pulse to the HOT base is properly shaped from the horizontal
oscillator onwards and nicely clipped at the base. Check the peak
shaping network across the HOT's collector isn't open. Check the damping
diode if a separate one is used. HV will also rise if zero beam or a
weak crt.


BP> From: bpetria@verizon.net (Brad Petria)
BP> Hi,

BP> I have a Magnavox TV chassis 27B502-00AA in my shop. I replaced
BP> the H.O.T. Q503 # 610597 (on device) which was shorted and the
BP> horiz. driver Q500 BSN274 # 483513047931 which was bad. I checked
BP> the regulated B+ which is 131.8V (130V is ideal). The HV measures
BP> 30KV when it should be 27KV - 28KV. Note: It can't be due to 1.8V
BP> high B+ since math shows an increase of about 400V (HV). I checked the
BP> FBT core and it isn't loose. Did you have this experience and what was
BP> the cause?
BP> Thanks in advance, Brad

BP> Tip for your old computer (reduce discard pollution too):

BP> If you can't sell your old computer, don't throw it away. Use it
BP> to backup your software by transferring files/folders from your new
BP> computer or laptop to it. I transferred my Windows folder and other
BP> stuff to my old computer using "PC Link", which I downloaded from
BP> www.simtel.net (cool site).
BP> http://www.simtel.net/pub/dl/52792.html (info or download)