[time-nuts] Thunderbolt issue found

Bob Camp kb8tq at n1k.org
Tue Aug 11 06:47:14 EDT 2015


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
> 
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