[TechAssist] Re: HELP! Goldstar VCR Model #GHV-1233M - Correct PS cap orientation?
- From: "George" <grndmstrg@xxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 10 Jul 2003 11:01:34 -0700
Don,
That's a positive voltage regulator, pin 1 is + input, pin 2 is ground and
pin 3 is + output so the markings are wrong and you installed it backwards.
Just use your voltmeter to verify polarity when in doubt.
George
Afana Electronics
Moreno Valley, CA
grndmstrg@xxxxxxxxxxxx
----- Original Message -----
From: "al m" <ampm@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, July 10, 2003 6:01 AM
Subject: [TechAssist] Re: HELP! Goldstar VCR Model #GHV-1233M - Correct PS
cap orientation?
> Positive lead should go to positive voltage. You have it in backwards.
> al marquardt
> ampm@xxxxxxx
> Al Marquardt Electronic Repair
> 206 W Main
> Girardville Pa. 17935
> ----- Original Message -----
> From: "Don Cohen" <bond007d@xxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Wednesday, July 09, 2003 11:55 AM
> Subject: [TechAssist] HELP! Goldstar VCR Model #GHV-1233M - Correct PS cap
> orientation?
>
>
> > Hello,
> >
> > This is an old 1986 model that customer really likes and wants fixed=
> > regardless of cost (to a point). Left side deck gears (looking from
> front)=
> > were broken, so I replaced the whole deck with one from a newer model=
> > junker with same deck - gears looked fine. I did all the usual
> maintenance=
> > and also replaced 3 caps on the power supply board. When I plugged unit
> in,=
> > it looked like it was doing a reset operation, but something seemed=
> > binding, with the mode motor continuing to turn when it should have
shut=
> > off. After about 5 seconds, there was a horrific pop and one of the
caps
> I=
> > had replaced blew up. There was no previous problem with VCR other
than=
> > maintenance and broken gears. That cap was C112 on the power supply
> board=
> > and is a 100uF/16V. I tested it before I put it in with an ESR meter
and
> it=
> > tested fine. Since the whole outer case blew right off, I am not able
to=
> > check to make sure I even put it in correctly (polarity), but I am
> pretty=
> > sure I did, as I always check that before finishing. I did not make
note=
> > when I pulled it out if the part marking matched the silk screen info.
I=
> > know that sometimes they are marked wrong. The silk screen on board
says=
> > that the + leg goes to the center pin of IC102 (positive 9 volt
> regulator=
> > AN78M09). That pin is ground. Also according to the silk screen, the=
> > negative leg is supposed to go to pin 1 of IC102, which is Vin. On the=
> > newer unit that I robbed the deck from, the power supply is designed=
> > differently, but the same regulator and cap are there (except the
> voltage=
> > on the cap had apparently been upgraded to 25v) and the orientation is=
> > reversed for the cap - neg leg of cap to center IC pin and positive to
> pin=
> > 1. That is what I would expect.
> >
> > So, does anyone have an old schematic or service bulletin that they
could=
> > verify that the silk screen info is indeed wrong? If not, does it
sound=
> > correct that the cap's + leg should not go to the IC's (and board)
> ground=
> > pin? Obviously I could just try to put another in again the way the
silk=
> > screen says and assume I somehow put it in backwards, but I would
rather=
> > not keep blowing parts and possibly doing other damage till I figure
out=
> > what the issue is.
> >
> > Much thanks to anyone that can help out here.
> >
> >
> > Don Cohen
> > DC Electronics
> > Shinglehouse, PA=20
> >
> >
>
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