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Plasma service manuals, no PS or syscon schematics?

J

jango2

Jan 1, 1970
0
Hi folks,
How come plasma service manuals come without a power supply and syscon
schematic ? I paid 25 US$ and i'm told manufacturers never publish PS
schematics in the service manual. Incidentally the TV i'm trying to
fix is a Hitachi 42PD7800TA Plasma display panel. The ps is made by
Murata MPF7415. The Murata website offers no info on the ps either. I
guess thats understandable ...OEM.
Symptom: Set clicks on (relay sound) some supplies are available, 30
volts measured at 35, Vs and Va are both very low ( 5 volts instead of
63) and then the set clicks off (protect?)
The power control pin of the ps seems to recognise 0.05 volts as an on
signal. If i disconnect that then the set wont turn on at all. The set
trips within 2 seconds from power on. Any clues? The manual i've got
is 16 Mb. Does anyone here have the full manual? How big is it? Even
the syscon section is missing from the manual.
Jango
 
J

Jumpster Jiver

Jan 1, 1970
0
jango2 said:
Hi folks,
How come plasma service manuals come without a power supply and syscon
schematic ? I paid 25 US$ and i'm told manufacturers never publish PS
schematics in the service manual. Incidentally the TV i'm trying to
fix is a Hitachi 42PD7800TA Plasma display panel. The ps is made by
Murata MPF7415. The Murata website offers no info on the ps either. I
guess thats understandable ...OEM.
Symptom: Set clicks on (relay sound) some supplies are available, 30
volts measured at 35, Vs and Va are both very low ( 5 volts instead of
63) and then the set clicks off (protect?)
The power control pin of the ps seems to recognise 0.05 volts as an on
signal. If i disconnect that then the set wont turn on at all. The set
trips within 2 seconds from power on. Any clues? The manual i've got
is 16 Mb. Does anyone here have the full manual? How big is it? Even
the syscon section is missing from the manual.
Jango

The manufacturers don't want you to repair the boards. They want you to
buy a replacement board at a ridiculous price or replace the whole TV.
The service manual should be enough to help you determine which board is
defective and then it's up to you to find a replacement, and hope that
the plasma panel is not loading down the PS and blow it again.
 
J

Jumpster Jiver

Jan 1, 1970
0
Jumpster said:
The manufacturers don't want you to repair the boards. They want you to
buy a replacement board at a ridiculous price or replace the whole TV.
The service manual should be enough to help you determine which board is
defective and then it's up to you to find a replacement, and hope that
the plasma panel is not loading down the PS and blow it again.

....Also, if you know which board is defective you can often find and
replace the defective components - if they are available.
I've seen custom hybrid power modules that are not available to anyone
but the board manfacturer in some sets.
 
As a last resort you can try to email the manufacturer of the ps
unit and ask them for the schematics, some out there will willingly
supply the information, I have done that with a bestec supply a few
years ago, first of all they sent it in taiwanese but after another
email asking for it in english they sent that 1 to me too.
Good luck.
--
 
J

jango2

Jan 1, 1970
0
Damn X and Y sus schematics are missing too. I got 4 shorted IGBTs so
far GT30G131. I refuse to let this deter me. I'm a chip level repair
technician and i will NOT be made redundant. screw you Hitachi.
 
J

jango2

Jan 1, 1970
0
I forgot to state the shorted IGBTs are on the Ysus board, PS seems ok
when i disconnect vs and va from load (xsus ,ysus)
 
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