[Heath] SG-7 Help

[The Pollacks]

The 150 is mmf (uuf or pf, now), not 150 mf.  This from an SG8 schematic.  I
think the main difference in the units is the 8 has a 12AU7 instead of 2
6C4s.  (The newer one is really 2 6C4s in one envelope).

I would probably change the filter caps, 2 20 mf units, but leave the others
alone unless there seems to be a problem.

More good sources for parts:  http://www.radioantiques.com
http://www.justradios.com
These caps, both electrolytic and smaller values are readily available and
inexpensive.
Ron K2RP
Encinitas, CA

-----Original Message-----
From: heath-bounces at puck.nether.net [mailto:heath-bounces at puck.nether.net]
On Behalf Of Garey Barrell
Sent: Sunday, September 30, 2012 8:54 AM
To: Ron Kramer; Heath
Subject: Re: [Heath] SG-7 Help

Ron -

The 150 pF (or mmf as it's on the schematic) should be a silver mica as it's
part of the frequency determining circuitry.  The original is probably good.

The 0.1 and 0.02 should probably be film type caps as they are the modulator
circuit.  Probably bad.

The rest are all bypass capacitors and may be common disc ceramics.  These
are almost always good as well.

I would also suggest replacing the two 20 uF @ 250 VDC (may be in one
tubular package with three
leads) electrolytic capacitors and the selenium rectifier (replace with
1N4007 diode).

I'd also check all the resistors with an ohmmeter to ensure they are within
+/- 10% of the marked value.  Several probably are NOT.

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

Ron Kramer wrote:
> I am rebuilding the unit and am looking for these caps:
> 150uf   Qty 1
> .001uf   Qty 2
> .01uf   Qty 3
> .002uf   Qty 1
> .05uf   Qty 1
> .01uf   Qty 1
> The caps are all rated at 600v. Are these electrolytic caps? The 
> schematic does not show a +/- on each cap.
> Does anyone have some to sell on know where I could find them?
>
> --
> Ron KD6EDV
>
> SKCC# 3551
>
> FPqrp# 2132
>
>
> _______________________________________________
> Heath mailing list
> Heath at puck.nether.net
> https://puck.nether.net/mailman/listinfo/heath

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