[ARC5] Request for help, aligning BC-453-B.

[Bill Cromwell]

Hi Les,

First - when you say "The "pip" on the main dial was broken" what do you 
mean by "pip"? The diamond "pointer" at top center or the index pin the 
holds the dial plate in alignment on the shaft? I first interpretted 
your version of English to mean the pointer at top center but now 
suspect you mean the index pin. Without the index pin you will have to 
just make a wild guess where the dial actually should be. It is 
unfortunate that the pin broke off. You have to try to get the index 
hole in the dial plate aligned over the broken off pin somehow. Maybe 
bright light will be sufficient for you to see the broken pin under the 
hole. You can't just guess at where the dial plate should be (well you 
can but it will take a lot longer). Is it possible for you to get the 
broken piece out and replace the index pin? In one of mine the pin 
simply fell out. Lucky me I found the pin and put it back in. If that 
happens with yours then it's your lucky day! Maybe a sewing needle can 
be your friend.

The inductors in the front end are not intended to be adjusted. The 
trimmer and padder capacitors for the oscillator - C4E and C9 
respectively - are wired in so as to serve the same function as the 
inductor low and cap high that you are familiar with. If you go back and 
forth between the two adjustments (as described in the instructuctions) 
and you can't get the two alignment points on the dial you'll have to 
revisit that index pin problem. Move the dial index on the shaft and 
start over. Repeat and repeat as necessary. When you get the dial plate 
indexed so that the rest of the hardware can work then ARC-weld it in 
place and *never* move it again.

Other possibilities. Did you start by trying to setup the dial alignment 
or did you start with getting the I.F. set up on 85 kc? I don't know if 
the I.F. can get far enough "off" to throw the dial that far out (you 
said 10 kc). I am picturing you with a frequency counter directly 
reading the VFO frequency which I think should be 85 kc above the 
operating frequency as read on the dial. When the alignment instructions 
were written there weren't any digital counters but an LM could get you 
there. I'm pretty sure you have that part of it right.

73,

Bill  KU8H


On 01/28/2015 03:26 AM, Leslie Smith wrote:
> I wish to align the front end in my BC-453-B
>
> DOCUMENTATION.
> The procedure for aligning is described in the document NAVWEPS
> 16-30ARC5-501
> I put a copy of this document in Yahoo Groups, Files, ARC-5 Articles &
> Refs.
>
> The file name is:  ARC-5_Test & Alignment, NAVWEPS_60-30.pdf  (My name
> for above).
> See section 3 for detail.
>
> I include one page from that document, with extra info I added:
> It's called:  "ARC-5, Alignment info sheet.jpg"
> It's in the same folder.  That sheet shows the physical location of each
> adjustment point.  I added a table showing the specific frequency where
> an adjustment can be made.
>
> On the ARC-5 Yahoo group site, you have access to the info I'm using.
>
> SETTING THE MAIN DIAL.
> The "pip" on the main dial was broken, so the in first step I set the
> sig gen to 500kHz, and tightened the nut holding the main dial.  Maybe I
> should have done that at 200kHz, not 500kHz?
>
> ALIGNMENT.
> According to these documents, I align C4E at 520kHz (that worked)
> At the low end of the band I touch C-9 at 210kHz.  (Here is my trouble.)
>        <--- TROUBLE HERE --<
>
> Here is the problem.  I always understand alignment touched 'caps' at
> the high end of the band, and coils at the low end of the band.  That's
> not what this book says.  It says trim C-9 at 210kHz.  OK, When I swing
> C-9 from max to min pFs, I change the frequency very little.  If I set
> the '453 dial to 200kHz, my signal generator reads 191kHz.  In other
> words, at the low end I'm almost 10 kHz 'off'.
>
>   Maybe I should have set the dial at the 'bottom' end (200kHz) and then
>   trimmed at the top end of the dial?
>
> Any help welcome.
> Or, stated more precisely, help!
>
>
> Les
>