Never heard of #PolyPlay before. But there will be a talk about it at our open day on October 3rd. I'll definitely listen to it, it's a piece of contemporary history of the former GDR.
https://computermuseum-visselhoevede.de/vortrag-ueber-das-poly-play-am-3-oktober
#RetroComputing #FormerGDR #VideoGameConsole

Early Sunday was used to solder the last lines of the #KramerMC memory expansion. All lines are beeped, correct and not shorted. Now I have to wait for my memSIM2, which is in repair in the moment. The voltage regulator was melted, no one knows exactly why.
#RetroComputing #FormerGDR #KitComputer #ZilogZ80 #U880

Productive evening. Most of the work is done for the #KramerMC memory expansion. It only lacks of the voltage and controlling lines. But data & address bus are connected. Have to beep it out before doing a first test, maybe on Sunday.
#RetroComputing #64kB #FormerGDR #KitComputer

After some searching I found the problem in #KramerMC. The #DS8286 on the cpu board gets in the way. In addition, it is installed incorrectly because the inputs and outputs are bridged. When I leave the socket empty it runs fine. Wonder if the computer ever worked the way it was intended.
Since I still had two of the plug-in contacts for the bus system in stock, I'm starting to build a RAM expansion to 64k. With address decoding to spare out 0000-0fff (ROM 2732) and 0fc00-ffff (display RAM). Because of the simplicity I decided to use 64k static RAM.
I'm also curious if the buddy might bring a new CPU board today, I'll be surprised.
#RetroComputing #Z80 #U880 #FormerGDR