Hi

Would like to fix two JVC switching power supplies...

Both have the same problem. Supply starts and switches OK but some voltages
are missing or fail under load.

The supplies are of the big old JVC type in the back right of the VCR which
consists of two boards with the connections and maybe fault on the left
(secondary) side.

Symptoms :

VCR loads casette but FF or REW stop after a few seconds. Drum does not
start, sometimes it does but power button flickers and capstan does not
start.
Most of the time the record level meters fail or flicker.

Have replaced the brown 105C electrolytics without sucess, have changed
whole power supply with one of a good svhs... former dead one works, so
fault is definitely in the power supply.

Have no schematics but two of them with exact same fault so believe it is a
known fault.

Would be very pleased to have help and or schematics

Merry Christmas and a Happy new Year
Michael from Austria

"gasper" wrote in message
. ..
Hi

Would like to fix two JVC switching power supplies...

Both have the same problem. Supply starts and switches OK but some
voltages are missing or fail under load.

The supplies are of the big old JVC type in the back right of the VCR
which consists of two boards with the connections and maybe fault on the
left (secondary) side.

Symptoms :

VCR loads casette but FF or REW stop after a few seconds. Drum does not
start, sometimes it does but power button flickers and capstan does not
start.
Most of the time the record level meters fail or flicker.

Have replaced the brown 105C electrolytics without sucess, have changed
whole power supply with one of a good svhs... former dead one works, so
fault is definitely in the power supply.

Have no schematics but two of them with exact same fault so believe it is
a known fault.

Would be very pleased to have help and or schematics

Merry Christmas and a Happy new Year
Michael from Austria


You're missing one or more caps. Don't know your model, but many JVC's had
bad 120uF at 6.3 volts caps bad, along the lower edge of the power supply
board. I just replace them with 100's or 220's, doesn't seem to make much
difference.

Mark Z.

Thank you mark,

I have often heard and researched the solution with the bad 120uf 6.3V
Cap.....

Unfortunately this must refer to a newer generation of JVC VCR,s , I believe
the VCR,s with the generation 15 drives and the funny loose tape guides....

But mine are all generation 12, the 3 motor drives with the old two pcb
power supply in the right corner. The pcb has partnumber 10166 regulator
pwb and switching pwb

Model Numbers are HRD 950 or HRS 5500 which use this kind of supply.

Of course I could try to replace all electrolytics but I even tried to
replace all 105C types in the secondary without sucess and I have problems
to get caps which are 105C and fit physically. It seems that the supply
fails under load.

Who has experience with this power supplies ?
Who can help ?

Thankyou
Michael


"Mark D. Zacharias" schrieb im Newsbeitrag
. ..

"gasper" wrote in message
. ..
Hi

Would like to fix two JVC switching power supplies...

Both have the same problem. Supply starts and switches OK but some
voltages are missing or fail under load.

The supplies are of the big old JVC type in the back right of the VCR
which consists of two boards with the connections and maybe fault on the
left (secondary) side.

Symptoms :

VCR loads casette but FF or REW stop after a few seconds. Drum does not
start, sometimes it does but power button flickers and capstan does not
start.
Most of the time the record level meters fail or flicker.

Have replaced the brown 105C electrolytics without sucess, have changed
whole power supply with one of a good svhs... former dead one works, so
fault is definitely in the power supply.

Have no schematics but two of them with exact same fault so believe it is
a known fault.

Would be very pleased to have help and or schematics

Merry Christmas and a Happy new Year
Michael from Austria


You're missing one or more caps. Don't know your model, but many JVC's had
bad 120uF at 6.3 volts caps bad, along the lower edge of the power supply
board. I just replace them with 100's or 220's, doesn't seem to make much
difference.

Mark Z.