JVC TV repair help

[James Peverill]

I am trying to fix my JVC AV27BP4 TV. The TV has no HV, the HOT
appears good but it has no startup drive. The startup drive is driven
by another transistor which appears good, and that just hooks to a big
JVC IC through a single resistor, the VC2024Z.
I'm not really sure where to go from here... I can't find any service
info on the tv, or a datasheet for the VC2024Z(yeah right!). Is it
likely that this IC could be bad? Or should I start checking all the
discretes around it... Any tips would be greatly appreciated!

 

[Sofie]

Is standby B+ getting to the micro? When power is turned on does the
jungle chip provide startup H-pulses to the H driver circuitry that feeds
the HOT? Is the power supply coming on and regulating properly to provide
B+ to the flyback?
These and lots of other things you can check without a schematic
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------------------


"James Peverill" <jamespev@net1plus.com> wrote in message
news:_RucnU3ko-tSHBqiU-KYvQ@net1plus.com...

I am trying to fix my JVC AV27BP4 TV. The TV has no HV, the HOT
appears good but it has no startup drive. The startup drive is driven
by another transistor which appears good, and that just hooks to a big
JVC IC through a single resistor, the VC2024Z.
I'm not really sure where to go from here... I can't find any service
info on the tv, or a datasheet for the VC2024Z(yeah right!). Is it
likely that this IC could be bad? Or should I start checking all the
discretes around it... Any tips would be greatly appreciated!

 

[James Peverill]

The b+ supply seems good, as do the other voltages (power supply seems
good). The JVC chip doesn't seem to be outputing anything.
I noticed something interesting... I turned the set on with the high
voltage leads to the yoke board disconnected (figured no high voltage
doesn't matter)... and oddly enough the high voltage seemed to fire up
for a half-second or so. Whould this indicate anything? Any ideas?
Thanks for your help!

james



Sofie wrote:

Is standby B+ getting to the micro? When power is turned on does the
jungle chip provide startup H-pulses to the H driver circuitry that feeds
the HOT? Is the power supply coming on and regulating properly to provide
B+ to the flyback?
These and lots of other things you can check without a schematic
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------------------


"James Peverill" <jamespev@net1plus.com> wrote in message
news:_RucnU3ko-tSHBqiU-KYvQ@net1plus.com...

I am trying to fix my JVC AV27BP4 TV. The TV has no HV, the HOT
appears good but it has no startup drive. The startup drive is driven
by another transistor which appears good, and that just hooks to a big
JVC IC through a single resistor, the VC2024Z.
I'm not really sure where to go from here... I can't find any service
info on the tv, or a datasheet for the VC2024Z(yeah right!). Is it
likely that this IC could be bad? Or should I start checking all the
discretes around it... Any tips would be greatly appreciated!