Re: G05 deflection board power transistors

oops! I mean '2N5876'.

The cross references should be:

    2N3716 -> NTE284 (NPN)
    2N3792 -> NTE284 (PNP)
    2N5876 -> NTE219 (PNP)

When I got the monitor both axis were using 2N3716/2N5876 pairs. One set
were "blown", both transistors being shorted across all terminals (both
polarities). The replacments I picked up were NTE284/NTE285 (not I was
replacing the PNP with the 2N3792 equivalent, NOT the 2N5876).

Didn't work (spot killer on). If I swapped P600 & P700 (effectively trading
the transistors between the two axis) I could verify that the Y yoke
deflection voltage was proper. So I'm certain it's the power transistors.

I then figured I needed 2N5876 replacements. If this was true I could swap
the 2N3716 & NTE284 and at least one axis would work (as measured across
R620 or R720). Now both axis HALF work! This leads me to believe the new
transistors don't work, which doesn't make sense (I observed proper static
precautions).

Any ideas? Has anyone else seen the 2N5876 in a G05?

/harry

>From: Rodger Boots <rlboots@cedar-rapids.net>
>Reply-To: vectorlist@synthcom.com
>To: vectorlist@synthcom.com
>Subject: Re: VECTOR: G05 deflection board power transistors
>Date: Sat, 27 May 2000 14:30:45 -0500
>
>The NTE book doesn't even show a cross for a 2N5786. Their web site says
>an
>NTE2347 will work. An NTE2347 is an NPN, but the 2N3792 it was used to
>replace
>is a PNP. You probably have blown parts in the driver stage now. You need
>to
>get rid of the 2N5786 and repair the drivers BEFORE installing a good
>output
>pair.
>
>There is a chance you read that part number wrong. The replacement isn't
>in
>anything close to a TO3 case style (what the chassis mount transistors
>are).
>It wouldn't be possible to mount one of these.
>
>
>Harry Collins wrote:
>
> > I'm trying to get a G05 deflection board working. I have narrowed down
>the
> > problem to the 4 power transistors, the 2N3716s & 2N3792s.
> >
> > On my deflection board the push-pull arrangement is made by 2N3716
>paired
> > with a 2N5786 (note a 2N3792). One set of amplifiers is fried.
> >
> > My replacement is to use NTE284 & NTE285, which does not work. If I then
> > pair these transistors with the existing 2N3716/2N5786 that work, I get
> > enough amplification to see something on the display (i.e. the spot
>killer
> > doesn't kick in).
> >
> > So what's the deal? I would think that the NTE284 is interchangeable
>with
> > the 2N3716, but when paired with a 2N5786 it is not.
> >
> > /harry
> >
> > ________________________________________________________________________
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>
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>
>
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Received on Sat May 27 18:38:24 2000