[Heathkit] Heathkit sb-620/ho-13 investigated by CIA

Fri, 05 Dec 2003 10:06:29 -0500

I have an SB-620 set up for the Heath IF and want to use it with my Collins
455 IF.

With the help of this list and other sources I did an extensive analysis of
the work necessary to convert the unit. I finally decided that it was not
worth the trouble, and risk, to retrofit the circuit with non-Heath parts
and an external mixer was a wiser choice.  A crystal controlled SA-602 mixer
would fit the bill and have a small parts count. An amplifier might be
needed to drive the SB-620.
The project is scheduled for this winter and will have to be done from
scratch, I have not seen any circuits or construction articles that address
this problem.

Before anyone asks, I am not willing to swap parts.

Jim

> C razy I nsane A mateur has delved into his archives and came up with the
> following posts he made sometime in the past.:
>
> Dan, Maybe this will help.  I think if somebody just did a little
> experimentation with
> available stuff and didn't get bogged down worrying about the details, a
> suitable solution could be had.  If you come up with any breakthroughs,
> please let the lists know.
> ----------------------------
> Post #1
>
> Every now and then, I see guys on the lists looking for the various coils
to
> change the HO-13 and SB-620 to different rcvr IF's.  I have uncovered an
old
> blueprint of those coils and I am posting the pertinent data here to whom
it
> may concern.
>
> I hope this does someone somewhere out there some good.  Maybe some of you
> old Heath guys can look at this and tell us what is pertinent so we can
see
> if there's anything out there available that is close enough to be a
> replacement without to much hassle.
>
> To wit:
>
> The 455 coil for the HO-13 is P/N 588 and has the following
characteristics:
>
> Range: (uH ) 117(max) to 275 (min)
> Preset:  123 �5% @ 790 kHz.
> "Q": minimum @ 790 kHz.: 57 measured with 2 1/4" leads to Q-meter
> Min. wire size: 3/41 litz
> Wire type: S. Cel. Poly.
> No. of turns:  Universal 133
> % of total turns from start to tap:  23%
> Viewed from above (screw adj. end):
> Start: lug #3 @ 6 o'clock
> Tap: lug #2 @ 9 o'clock
> Finish: lug #1 @ 12 o'clock
> Winding: Clockwise
> Staple lugs not to protrude inside coil form
> Form to withstand 1000 VAC terminals to core
> Must snap into 5/16" hole in 14 ga. aluminum
>
> P/N 589 was this high IF coil for the HO-13:
>
> Range: ( uH) 12(max) to 31(min)
> Preset:  23.6 �10% @ 2.5 MHz.
> "Q": minimum @ 2.5 MHz.: 80, measured with 2 1/4" leads to Q-meter
> Min. wire size: 3/41 litz
> Wire type: S. Cel. Poly.
> No. of turns:  Universal 43
> % of total turns from start to tap:  20%
> Start: lug #3 @ 6 o'clock
> Tap: lug #2 @ 9 o'clock
> Finish: lug #1 @ 12 o'clock
> Winding: Clockwise
> Staple lugs not to protrude inside coil form
> Form to withstand 1000 VAC terminals to core
> Must snap into 5/16" hole in 14 ga. aluminum
>
> On the SB-620, P/N's 775 & 776 are the same as 588 & 589 respectively, but
> they have a 4th (dummy) lug at 3 o'clock.
>
> 73,
> Tom
> --------------------------------------------------------------------------
--
> Post #2
>
> Well it took exactly 12 minutes to get my first 2 requests for the rest of
> the dope for the SB-620 coils.  So -- here goes
>
> P/N 774 (must have been from earlier production):
>
> Range: ( uH) 2.60(max) to 5.0 (min)
> Preset:  3.5 �10% @ 7.9 MHz.
> "Q": minimum @ 7.9 MHz.: 85 measured with 2 1/4" leads to Q-meter
> Min. wire size: #30
> Wire type: SPTH S. Cel.
> No. of turns:  19 1/2
> % of total turns from start to tap:  37%
> Viewed from above (screw adj. end):
> Start: lug #3 @ 6 o'clock
> Tap: lug #2 @ 9 o'clock
> Finish: lug #1 @ 12 o'clock
> Dummy: lug #4 @ 3 o'clock
> Winding: Clockwise
> Staple lugs not to protrude inside coil form
> Form to withstand 1000 VAC terminals to core
> Must snap into 5/16" hole in 14 ga. aluminum
>
> P/N 807:
>
> Range: ( uH) 3.8 (max) to 7 (min)
> Preset:  4.8 �10% @ 7.9 MHz.
> "Q": minimum @ 7.9 MHz.: 70 measured with 2 1/4" leads to Q-meter
> Min. wire size: #38
> Wire type: S. Cel. Poly.
> No. of turns:  Universal 18 1/2
>  Turns from start to tap:  6 1/4
> Viewed from above (screw adj. end):
> Start: lug #3 @ 6 o'clock
> Tap: lug #2 @ 9 o'clock
> Finish: lug #1 @ 12 o'clock
> Dummy: lug #4 @ 3 o'clock
> Winding: Clockwise
> Staple lugs not to protrude inside coil form
> Form to withstand 1000 VAC terminals to core
> Must snap into 5/16" hole in 14 ga. aluminum
>
> and P/N 808:
>
> Range: ( uH) 27(max) to 56 (min)
> Preset:  44�10% @ 2.5 MHz.
> "Q": minimum @ 2.5 MHz 60 measured with 2 1/4" leads to Q-meter
> Min. wire size: #38
> Wire type: S. Cel. Poly.
> No. of turns:  Universal 57 1/2
>  Turns from start to tap:  16 1/4
> Viewed from above (screw adj. end):
> Start: lug #3 @ 6 o'clock
> Tap: lug #2 @ 9 o'clock
> Finish: lug #1 @ 12 o'clock
> Dummy: lug #4 @ 3 o'clock
> Winding: Clockwise
> Staple lugs not to protrude inside coil form
> Form to withstand 1000 VAC terminals to core
> Must snap into 5/16" hole in 14 ga. aluminum
>
> FWIW, the coil forms vary between 1 1/4" and 1 1/2" in length.
>
> You guys please keep the list informed of any breakthroughs.
>
> Tnx,
> Tom
> ------------------------
> Post #3
>
> A few more tid-bits:
>
> FWIW: the part nos. I posted should all be preceded by "40-".
>
> Also:  40-588 & 40-589 were vintage 1963 pieces that became obsolete
> 2/28/66, at which time 40-774, 40-775, and 40-776 were introduced.  Then,
on
> 11/21/66 the 40-774 became obsolete, and the 40-807 & 40-808 were
> introduced.  I have no other revisions beyond 9/15/67.
>
>
> Vy 73,
>
> Tom
>
>
> ----- Original Message ----- 
> From: "DAN COTSIRILOS" <[email protected]>
> To: <[email protected]>
> Sent: Friday, December 05, 2003 9:34 AM
> Subject: [Heathkit] sb-620
>
>
> >Hello
>
> >    I have a sb-620 scanalyzer with a 455 kc coil. Does anyone know if
the
> other if coils >can be made or are the parts obsolete?
>
>
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