[time-nuts] Thunderbolt issue found

paul swed paulswedb at gmail.com
Tue Aug 11 09:19:19 EDT 2015


Agree with Bob. The fact that the top is blown off sounds like a bit of
lightning.
You can easily adapt a classic npn or pnp in for a temporary test. 3904 or
3906.
I have needed to do this on other things. It confirms quickly thats the
issue and then you just need the new smt to solder in.
I fear you nightmare may just beginning.
Good luck.
Regards
Paul
WB8TSL

On Tue, Aug 11, 2015 at 6:47 AM, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> It’s a pretty good bet that what ever is *really* is a generic PNP or NPN
> device will drop in. You need a low frequency device like the 3904 series.
> It’s going to carry about 40 ma to your antenna. A high(er) current part
> (Ic max > 100 ma) is
> better than a low(er) current (Ic max < 20 ma) part in this case.
>
> Bob
>
> > On Aug 10, 2015, at 9:12 PM, Chris Waldrup <kd4pbj at gmail.com> wrote:
> >
> > Hi Everyone,
> >
> >
> > Thanks for the suggestions this past weekend for helping get my new
> Thunderbolt fixed. I got back into town last night late so couldn't tackle
> it until tonight.
> > I put a DMM on the F connector and I didn't have 5V on it. Opening up
> the case, I found the top blown off one of the SOT package transistors.
> It's the one closest to U19 and is connected to this chip's pin 14.
> > I have the Thunderbolt with the three separate input voltages (5,
> -12,12). Does someone have a board they can look at and let me know the
> code on the transistor so I can see about a replacement?
> > Maybe even a closeup shot of the 5 SOT packaged devices in that area as
> I may find another is bad.
> > Thank you in advance.
> >
> >
> > Chris
> > KD4PBJ
> >
> > —
> > Sent from Mailbox
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