Recent content by ppieczul

Amiga 3000 daughter board wanted, the one that has zorro slots and plugs into the motherboard.

Does a PCB project exist for A3000 daughter board? I am missing one in my A3000. Thanks.

Looking for owners of a Kwarc / Quartz / Кварц - Soviet ZX Spectrum clone The machine looks like that: It has written: Кварц игровой компьютер (Quartz game computer) I am looking for someone who has it and can send me EPROM content, which is broken on my machine. Thanks Pawel

Hi, I saw a few posts here from 10 years ago and people claim they had found this document, but it was not made available. Does anyone have and can share this service manual? Thanks Pawel

I am in need for Apple III PROM 342-0061 at motherboard location C11. Does anyone have spare to sell? Is it possible to burn in a new prom assuming I could get unused parts? I could not find PROM images anywhere on the Internet. Thanks Pawel

Hi, I am fixing my Apple III machine. The first symptoms are that it does not show anything on the screen. Apart from that, it is possible to ctrl-reset it, it will kick off the FDD, or to ctrl-apple-reset it and it seems to go into debug mode, there are beeps in response to some commands...

Hi, I have a Sinclair Amstrad APC 386 SX, also known as Amstrad 3386 SX, complete main unit with original 40MB Seagate HDD. There is practically zero documentation on the web of this machine. Does anyone have anything related to the motherboard, jumper configurations and keyboard protocol? I...

So here is a schematic of the board. Now you can see how RCA and DB9 are connected. Combining this with the ROM listing, it should lead somewhere, but I have no more time today.

Dump of ROM content: And the disassembly, it actually looks like making some sense, though I have not yet tried to analyse it: ORG 00007H DIS I ; 0007 DIS TCNTI ; 0008 SEL MB0 ; 0009 SEL RB0 ; 000A CLR A ; 000B MOV R2,A ; 000C MOV R3,A ; 000D MOV R4,A ; 000E MOV R6,A ...

Here you go. When I find some time I will dump the ROM and see with oscilloscope what is at the RCA. It seems like MCS 48 type of microcontroller, we should be able to disassembly it or maybe even emulate.

Hi, I am restoring Compaq Portable III. It is a version with cmos battery integrated with the real time clock chip. This chip was missing on my board - probably battery leaked and someone removed it. I put an MC146818P instead (without integrated battery) and the computer reports no more board...

Hi, In one of the old 286s I found the Computek PCM210 card. It uses only power from the ISA slot and has two connectors: DB9 and RC. It has NEC8506 CPU on it and EPROM. Seems like a microcontroller thing - any idea what this might actually do and why in a PC? Thanks Pawel

Hi, I am restoring an old Commodore PC SL386DX-16. It was completely dead, so far I replaced the 82C215 address/data buffer chip and fixed a lots of broken traces on the board. Now it started to boot BIOS and immediately reports an error with a beep sequence 4-1-3-1 and this sequence is...

Hi I have arche rival 286 motherboard with WD1003-WA2 controller. It works fine with FDDs both 3.5” and 5.25” but I can’t make it work with MFM HDD. It basically waits in bios on booting a couple of minutes and reports hdd initialization error. I tried two controllers (same model) and two...

Hi, I continue my adventure with PET 3032 and now it is time to get 8050 drive working. I finally got a cable, connected it and bought some old but new and never used DD floppies. The drive seems to initialize correctly - it ends up with center green led on. I tried formatting the disk and got...