Pocket Computer 4 printer (more)

So, here's more details about what I did (along with pictures).

The green/black wires used to be hooked up to the battery.  The yellow/purple (hard to see since I cut most of them away - near where the black/green wires attach to the circuit board) used to be hooked up to the AC adapter plug.

The green wire is negative and it's hooked up to the center pin.  The AC adapter that I used...

is something I picked up at the "junk store" and is just a 6V power supply.  I normally use these with my TRS-80 Model 100/102s.

The original battery pack was a set of 4 AAA NiCd rechargeables, so 6V was right.

Side note: I tried a couple of other "6"V power supplies, but they were showing me 9-10V on my volt meter.  Strange.

Anyway...  it's working.

Sorry for the sideways video.  I had hoped that it would have auto rotated.

All I did was a simple program that loops 1-20 and displays the number and the number multiplied by 10.  I used Mode 7 to send the output to the printer.

Notes:
1. This will not work with the cassette interface hooked up.  Only with the printer directly connected.  I don't know why.  But since I use the cassette interface so rarely, I probably won't look into it.
2. You must have the power supplied to the printer before turning the PC-4 on.  Otherwise, you'll get an Err 9.

But overall, I'm pretty happy.  I liked working with these.  It was a nice learning experience.