🇩🇪 Robotron KC 87: Part 3 (Loading Software) [TCE #0557]
32Finally, I figured out how to load software (i.e. RTFM in German) on this East German computer. I re-assembled the machine sans internal power supply ... I'll keep using the external Mean Well for now (it doesn't seem that I need the -12VDC unless I use the serial port?).
I could just mount a 5-pin DIN on the case and make it permanent ...
00:00 ... Intro
01:28 ... Converting video output
05:25 ... Testing baseband video output
05:48 ... Reassembling the case
06:25 ... Dad's Blu-Tack trick
10:59 ... Discussion about Tiger prawns for Xmas lunch
14:24 ... Reassembly continues
16:20 ... Power-on test
19:15 ... Making the cassette cable
20:26 ... Trick to increase text brightness
22:59 ... How to load BASIC programs (finally)
26:26 ... Loading OTHELLO (R+OTHELO)
30:31 ... How to load machine code programs (finally)
31:26 ... Bumbling around RAMTEST
33:03 ... Channel thanks & outro
For generating WAV files, I used a Perl script from this page that converted the TAP format files into WAV:
https://hc-ddr.hucki.net/wiki/doku.php/z9001/kassettenformate
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From Part 2:
I have a Mean Well GP25A13A-R1B with a 5-pin DIN plug that outputs ±5VDC and +12VDC ... I can't really see any use the the -12VDC on the board (maybe serial, but I'm not interested in that for now) so let's give that a try.
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From Part 1:
The Robotron Kleincomputer (Small Computer) KC 87 is an East German (or DDR if "East Germany offends you) microcomputer released in 1987 and designed around their U880 (or UB880) processor, their clone of the Z80. The other computers in this range were the Z9001 and the KC85/1 ... not to be confused with the KC85/2, KC85/3 and KC85/4 that are different computers produced by a different factory.
An ASMR description of the computer ... 🧐
• Soft Nails ~ ♥ [ASMR] Kleincomputer Ro...
https://nadjabuttendorf24.com/kc87.php
Maybe the PSU schematic:
https://www.sax.de/~zander/kc/kcsch_6.pdf
Some other interesting links I've found:
https://oldcomputer.info/8bit/kc85_1/index.htm#pin
https://hc-ddr.hucki.net/wiki/doku.php/z9001
https://oldcrap.org/2018/05/02/robotron-kc-87/
Discussion about replacing the 166-5551 encapsulated mains filter (in German):
https://www.robotrontechnik.de/html/forum/thwb/showtopic.php?threadid=16520
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https://karlcasey.bandcamp.com/
/ @whitebataudio