Don Lerche was right and I thank him so much! Although I could not SEE
the short I disconnected the T4 windings one by one until the Q7 base
resistance shot up to 2.6k. Then I resoldered one by one - measuring Q7
after each new solder joint. Finally I redid all of the page 71
measurements and I'm back in business! It is so nice to be able to get
some help on a Sunday afternoon and go to Alignment Part III!!!!
73/Tim NZ7C
Don Lerche wrote:
Tim,
Yes, the resistance should be between 2500 & 3000 ohms. As you say a short
on Q7 itself should be obvious, so if nothing looks bad, then after having a
look at the schematic a good place to look may be around T4. There is a
ground connection to winding 3-4, so a short around here to winding 5-6
would put a ground onto the base of Q7.
Good hunting
73 Don, M1DIC
K2/100 #3082
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED]
Sent: 30 January 2005 18:56
To: elecraft@mailman.qth.net
Subject: [Elecraft] Q7 base resistance test - low reading
Hi folks -
I just completed the RF board and am doing the resistance checks on page 71.
For Q7 base it requires 2.5 - 3.0 k. My DVM onky meausres .4 ohms - no
where near 2300 - 3000 ohms. I assume this means I have a short. There is
no short between the soldered pads on Q7 and I rechecked the mounting screw
hardware to make sure each part was correctly in place. All other
measurements for the RF board are OK.
Not being anything but a paint-by-number solderer, am I reading the table
correctly? That does mean 2500 - 3000 ohms write? If so, I very stumped
because a short on this component should be very obvious - but I don't see
it. Can someone offer some help please? Thank you very much in advance.
73/Tim NZ7C
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