[TenTec] The Argonaut 509 From HELL!

[Richard Arland]

The latest installment: 12-6-04

Several of you have replied off-list to check out the crystal for 10M. 
Unfortunately, I can't find any crystals (the IF aside) at all. The 
oscillator board is all LC free running oscillators.

Now for the really bad news: The doubler/tripler transformer, T1, is so 
badly out of alignment that it is erratic. Sometimes it will triple on 40 
meters (like it is supposed to) but then it will also triple on 15 meters 
instead of double, which it is NOT supposed to do! By tweaking the coils, I 
can get it to double on 15 M but then it will only double on 40M, which puts 
me at 10.7 MHz This is not a good thing! I was actualy tempted to remove the 
oscillator/VFO board from the T-T Model 315 receiver and tryi it in the 509, 
however, the 315 board uses a regulated 7VDC and the 509 uses a regulated 
9VDC. OOPS! The basic and injetion frequencies are the same, however. I may 
try this as a desperate "last action".

I spent about 3 hours today trying to align the oscillator stages on the 
oscillator sub-assembly. It took that long to get the hang of how the two 
coils per band interact with each other. Now I have four of the five bands 
tracking pretty good, but 15 M is unusable due to the Injection Frequency 
tripling to 18 MHz instead of only doubling to 12 MHz. So, I got a partial 
"win" in that I have a useable radio on 80, 40 & 20M (At this point I'll 
take what I can get!)

Oh, yeah, I broke one of the leads on Q1 on the audio board due to all the 
handling of the chassis with the front panel removed. It is an MPSU10 which, 
of course, I can't cross to anything I have in the shop (that's a big 
surprise). Anyone got a suitable sub? (I know...."make one outta wood".)

Well, that's it for today's installment. I copied the previous e-mail 
posting to the T-T lab, but they have not replied, since I asked them some 
specific questions. In the "old days" they kept a supply of boards and 
sub-assemblies at the T-T lab and all you had to do was send them your 
misbehaving board and they would send you a new one (and bill you, of 
course).

At any rate, I am now looking for another 509 in good electrical shape. I 
can always use the case and end panels/top of mine on the nw 509 to make it 
look pretty.

More later.

73 es Happy Holidays

Rich K7SZ