DX-100

[Stewart D Lyon]

Hi Wayne,
What I have before me is a DX-100 schematic. What I don't have is a way
to send it to you except by mail.  Therefore I'll try to describe it to
you.

The transformer has three filament type windings and one multi-tapped HV
winding.

The first filament winding is 5V-4A and goes to pins 2 & 8 of  the 5R4 HV
rectifiers. This winding should be well insulated since it has the high
HV on it.

The second is 5V-2A and goes to pins 2 & 8 of 5V4 LV rectifier

The third filament is 12.6V-4A CT.  The center-tap goes to ground and
some tubes are hooked to one side of the winding and some to the other.
The 1625s, pins 1 & 7 are connected across the full winding.

The HV winding is described as 634VCT-150mA with taps at 120VCT-20mA.
The 634V winding goes to pins 6 & 4 (plates) of the 5V4.  This provides
the "medium" HV whose value is not stated. The output of the rectifier
goes to a capacitor-choke-capacitor filter (pi) so it's probably around
250-275VDC.
The 120V taps go to pins 1 & 5 (cathodes) of a 6AL5 bias rectifier. The
bias voltage is filtered with a cap-1K resistor-cap and is probably abt
-120 VDC.
The center-tap is grounded.

The schematic gives NO color codes for the wires but with the pin numbers
you should be able to work backwards.

I built and used one of those monsters when they first came out. Really
loved it.   As I recall the VFO was drifty but otherwise was a fine rig.

Hope this helps and good luck with the transformer rewinding. I've done
it and it's no fun.
73, Stu - W6CUX
Winnetka, CA
ARRL Life Member (proudly!)

On Thu, 23 Jul 1998 13:04:52 +0800 Wayne Tangey <vk6ft at INF.NET.AU>
writes:
>Hi all, I'm new to the list and have a big ask. Does anybody on the
>list
>have a circuit for the DX-100 AM/CW rig that they can scan & email to
>me,
>just the power supply would be fine. Failing a copy of the circuit
>does
>anyone know the correct secondary voltage outputs of the low voltage
>xformer
>as per the color code used. I got the manual with the rig but no
>circuit and
>the manual gives no clue to the voltages. Obviously the filament
>windings
>are easily worked out but there is a couple of higher voltage windings
>by
>the look of it. Why do I need them ?  Well here down under (Australia)
>we
>run on 240 AC mains, some drongo plugged the beasty (110 volts) into
>the
>mains and the rest is history. A replacement transformer or a rewind
>is now
>in order.
>
>
>Cheers Wayne Tangey - VK6FT. Perth, Western Australia
>
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