[Coco] CoCo1 Rev E 64K Upgrade by Kitsz

[theother_bob]

Oh, I see what I did. Duh! I typed in step 6 in place of step 5, which should read:

5. Solder or jumper together the two staking pins to the left of C44. Preferably, connect these through a 33-ohm resistor or a ferrite bead.


It's hard to find good help these days!
Bob


----- Original Message ----
From: Darren A <mechacoco at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Sunday, September 14, 2008 12:35:19 PM
Subject: Re: [Coco] CoCo1 Rev E 64K Upgrade by Kitsz

The instructions you listed don't mention anything about R83.  Perhaps
that is in Step 6 which appears to be missing. I've seen two other
documents say that a 33 ohm resistor needs to be soldered to those
pins. My board has a jumper between those two pins rather than a
resistor. Does anyone know if that could cause a problem?

Darren

--------------

On 9/14/08, theother_bob wrote:
> For the sake of a quick reply I am typing in the relevant portion of the
> article so you don't have to wait for me to set up my manual scanner. This
> is from The Color Computer Magazine, Oct. 1983, Custom Color by Dennis
> Kitsz, pp31-48 (wow! a mini-mag in itself, covering the lowerkit, 64k
> upgrades for all models up to NC board and installing aftermarket keyboards
> in the CoCo.)
> -----------------------------
>    64K Upgrade, Radio Shack style--Rev.E. Needed: screwdriver to open the
> case, snips, solder and iron, thin wire, eight 64K RAMs (type 4164/4864).
>
>    1. Unplug and open the computer
>    2. Remove the RF interference shield by cutting the white plastic straps
> and working the cover around the edges.
>    3. Move four jumpers (one between U4 and U8, and three above the keyboard
> connector) up and over to the 32K position.
>    4. Move the remaining umper (below C44) up and over to the 16/32K
> position.
>    5. Solder or jumper together the two LO staking pins next to U29.
>    7. Carefully remove U29 from its socket, and bend pins 4, 5 and 6 up and
> parallel to its body.
>    8. Remove U11 from its socket, and bend pin 5 up and parallel to its
> body.
>    9. Replace U29 and U11 in their sockets, except for the pins noted.
>    10. Connect three wires: from U29 pin 6 to U29 pin 8; from U29 pin 4 to
> U11 pin 5; from U29 pin 5 to TP1.
>    11. Clip out capacitors C61, C31, C64, C35, C67, C45, C70 and C48.
>    12. Remove the eight 4K or 16K memory chips U20 through U27.
>    13. Install eight 64K memory chips, pointing in the same direction.
>    14. Restore the interference shield and press it down, replace the cover,
> and power up.
>    15. PRINT MEM should reveal a 32K machine.
>

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