B&O LX2802
 

Goes to black screen after short warm up (10-30 sec). Measured hor. drive,
this should be 230 Vpp but changes from ca 50 to 150 Vpp. The rate of change
is 50 Hz (the same as line freq. -230v / 50Hz). Should I go for a defective
line trafo ( somehow leaking?) or a defective deflection coil? Due to the
low freq. of the oscillation, I don't think it's bad caps, as could be
expected with high oscillation... Def. coil resistance: hor = 2.0-2.1 ohm,
vert = 6.5 - 6.6 ohm
Any ideas?

Please tell me what is a Line Trafo ?

kip

john wrote:
Please tell me what is a Line Trafo ?

LOPT

---
Met vriendelijke groet,

Maarten Bakker.

By Line trafo I mean the transformer, seperating HOT and cold circuit in the
TV. It usually have around 18 pins. 4-6 on the primary side, the rest on the
secondary side. I belive bad insulation inside it could make it possible for
the line power to get through somehow. Measured B+ seems like a mixture of
proper B+ and power line voltage. Anyway, I'll try to swap it. Not shure if
my spare is working either...

"john" skrev i melding
.. .
Please tell me what is a Line Trafo ?

kip

Look into the SMPS section for bad caps.

kip

Den Tue, 07 Dec 2004 18:19:36 +0100. skrev Murbolt:

Goes to black screen after short warm up (10-30 sec). Measured hor. drive,
this should be 230 Vpp but changes from ca 50 to 150 Vpp. The rate of change
is 50 Hz (the same as line freq. -230v / 50Hz). Should I go for a defective
line trafo ( somehow leaking?) or a defective deflection coil? Due to the
low freq. of the oscillation, I don't think it's bad caps, as could be
expected with high oscillation... Def. coil resistance: hor = 2.0-2.1 ohm,
vert = 6.5 - 6.6 ohm
Any ideas?

Here are the components you always change when they comes to service

+4C28 (220µF/16V)
+4C29 (100µF/16V)
+4C34 (6.8nF/1500V)
+4C32 (1.8nF)
+4C32 (1.5nF)
-4C35 (18nF)
+4TR15 (BC369)
+4TR11 (BU508A)
-53C46 (100nF/63V)
+-53R63 (pot 2K2)
-53C48 (10nF/2.5%)
-53C45 (10nF/20T)

+ = always
- = not nesseseraly
+- = depends what in from birth

Further modul 04 replacements :

4C26
4C54
4TR9
4R63
4C48
4C47
4C44
4C45
4C49
4C14
shortcircuit P26-4 and P26-2

at modul 26/27 replace :

C640

at modul 01/51 replace:

Tr1
Tr2
Tr3
Tr11


Happy soldering

--
Best whishes

Christian Treldal

Murbolt wrote:
By Line trafo I mean the transformer, seperating HOT and cold circuit in the
TV. It usually have around 18 pins. 4-6 on the primary side, the rest on the
secondary side. I belive bad insulation inside it could make it possible for
the line power to get through somehow. Measured B+ seems like a mixture of
proper B+ and power line voltage. Anyway, I'll try to swap it. Not shure if
my spare is working either...

This is commonly referred to as SMPS transformer or supply
transformer... Line is mostly used as in line output transformer.

---
Met vriendelijke groet,

Maarten Bakker.