Panasonic NV F70 Hifi VCR power supply prob

[Ren]

Hi there.

I have a Panasonic NV F70 Hifi VCR that has a wicked power supply fault.
I received the Unit in DEAD state.
I have religeously gone through and replaced all the electrolytics.

While replacing the Electrlytics, i discovered a resistor (R25) to be
ruptured. (2.2 Ohm i believe)
This Resistor is located directly after the Bridge rectifier (D2).
It was Open Circuit.
What i need is a skematic just for the power supply module, so then i can
continue to trace what caused this fault.

I did replace the resistor , only to be greeted with what i anticipated. A
nice visual extravaganza of blown resistor

Any help would be Excellent.


Thanks

Ren(NZ)

 

[Bob Parker]

Hi,
Those Panasonic power supplies are prone to having shorted zener
diodes. If you check for shorted diodes, you might be lucky and not
need the schematic.
If you don't find any, my apologies for wasting your time.

Bob

 

[Sam Goldwasser]

Hi,
Those Panasonic power supplies are prone to having shorted zener
diodes. If you check for shorted diodes, you might be lucky and not
need the schematic.
If you don't find any, my apologies for wasting your time.

The shorted zener diode usually results in a whine but no smoke.

He sounds like he has a shorted main chopper transistor. Probably
should have gotten the complete rebuild kit.

It may be somewhat similar to this supply:

http://www.repairfaq.org/sam/vcrps.pdf

but I don't see any 2.2 ohm resistor.

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[Ren]

Hi Sam..

I think your right.
That Diagram is quite different from the Supply i have.

I think i'll try and bludge a diagram off a local electronics replair shop.

Cheers

Ren

 

[klawit]

Hi Ren,

is your VCR equipped with a non switched power supply of type VEP1248A
or VEP1261A?

This is the one built into my NV-H70. I have a schematic and I can
send you a scan if you like.

CU

klawit

 

[Ren]

Thanks Klawit..

The power supply module in this Unit is a Switching power supply.
In the mean time i have sorted out the Problem.
It was in the end the Regulator IC , that is located or clamped to the Side
of the Mudules Tin Cage.

Just this morning i received a New one, at a cost of $18.
Installed it, and away she went..


Thanks once again for making the offer.
I appreciate it..

Cya

Ren