Need DX--40 Expert

[Marshall]

Hello, Ron,

In late 1959, when I was studying for my novice amateur radio license, I
wrote to Heath Co. for information on a DX-40 transmitter to go with my
AR-3 receiver. They sent me a four page specification packet that had
a picture, specifications, schematic and block diagram description of
the circuit. The schematic has the components you list for your
schematic
#1 scenario.  The date on the lower left corner of the package is
8/3/59.
I have had this in a reference file folder since 1959. ( I never did get
the DX-40, instead, I built a transmitter out of a QST article in 1960.)
I hope this is helpful in dating your research.

Best regards,

Marshall Dues - WB5MYO
Katy, Texas


Ron wrote:
>
> I am in the process of doing a restoration on a DX-40 and I have come across
> two variations of the wiring schematic.  I wonder which is the most recent
> version.  Hope someone on this list can answer this for me.
>
> The differences are as follows:
>
> Schematic #1:  12AX7 Speech Amp plate supply line---has a 0.1mfd cap to
> ground
> Shcematic #2:  12AX7 Speech Amp plate supply line-- has a 20mfd 450V
> electrolytic to ground.
>
> Schematic #1:  6DE7 Modulator Tube--Pin 9 Cathode--10K 5W Resistor in
> parallel with .5mfd cap to pin 2 of function switch.
> Schematic #2:  6DE7 Modulator Tube--Pin 9 Cathode--12K 5W Resistor in
> parallel with 2mfd cap to pin 2 of function switch.
>
> snipped ...

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html