[AMRadio] SP200/BC1004B

[djed1 at aol.com]

Nope, not normal.  The RF gain should work when the AVC is on, reducing the gain of the receiver.  I often reduce the gain on the lower frequencies, where the noise level can run S-9.  Based on my two BC-779 and one SP-400. 
 On radios this old, you may find lots of PO wiring changes, mostly for the worst.  I had to rewire one of the BC-779s because it had been extensively modified, but the strangest mod was on the SP-400.  I picked the radio up locally, and it was in excellent condition.  I went through and recapped it, and it worked fine, except that the bandspread didn't work on the highest band.  Very strange- no obvious reason for a discrepancy-could it have been a factory miswire?  I finally opened up the tuner and found someone had been in there, carefully clipping the wire from the bandspread cap from the top band and soldering to the broadcast band.  I can't imagine why, but there it was- took me about 5 minutes to restore it to original working condition. So meter out all the AVC wiring.
Ed  W2EMN

 

 

 

-----Original Message-----
From: CL in NC <mjcal77 at yahoo.com>
To: amradio <amradio at mailman.qth.net>
Sent: Fri, Aug 9, 2013 12:46 pm
Subject: [AMRadio] SP200/BC1004B


I need a bit of info from someone who uses a SP200/BC1004 receiver.  I have one 
that I have restored electrically and it works fine except for the AVC.  Checked 
all the AVC circuitry and replaced any significantly changed resistors, caps in 
the RF deck have been replaced.  When AVC is off, the RF gain runs the rcvr 
fine.  Turn on the AVC, the RF gain has very little control, and the rig runs at 
what seems like full sensitivity, overloading on really strong stations.  The 
tube socket voltages are within acceptable variations from the book values. 
Going back to manual,  you can control those strong stations and make them not 
overload.  Does the SP200 series have AVC issues and this is normal for this 
RX,  or did I miss a part somewhere?

Charlie, W4MEC inn NC
______________________________________________________________
Our Main Website: http://www.amfone.net
AMRadio mailing list
Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/
List Rules (must read!): http://w5ami.net/amradiofaq.html
List Home: http://mailman.qth.net/mailman/listinfo/amradio
Post: AMRadio at mailman.qth.net
To unsubscribe, send an email to amradio-request at mailman.qth.net with
the word unsubscribe in the message body.

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html