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H7484 interlock tips for testing and troubleshooting.

VCFed about 6 months ago

Evening all! Over the winter I'm planning on repairing this H7484 power supply and chassis for a Vax 4000-100 system. I've sold the CPU and memory, but would like to use it for a seriously sized pdp11/84. Given that all slots are CD bus it should be able …
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Bomb Rush Cyberfunk Review or: How I Learned to Stop Worrying and Love this Spiritual Successor to Jet Set Radio

The Dreamcast Junkyard about 6 months ago

Jet Set Radio (or as it was known in North America, Jet Grind Radio) came skating onto the scene in the year 2000. Developed by Sega's in-house studio Smilebit, the flagship Dreamcast release saw players enrol in the rollerblading GGs gang to claim their t …

Homebrew S100 - CPU Board

VCFed about 6 months ago

Well, after many months of digging through documents, schematics, and websites, I have finally gotten my CPU card designed, and built. Part of it is based on the STD bus Z-80 board I use in my development system and the rest is based on designs from Ithaca …

8-bit acorn hardware • Slowing down power up on a BBC Model B?

Stardot about 7 months ago

So you maybe opened this wondering why? Well… I am building a new Beeb in custom console style case (TBD) and the vision behind it is to have it startup ready to go, with a CoPro and HD emulated through the CoPro and 1MHZ bus shifter boards. I recentl …

Intel Aboveboard Plus 8, PC selection jumper / shunt

VCFed about 7 months ago

Hi All, My first post here but I have been lurking for a while. I have a Intel Aboveboard Plus 8 that I would like to use in an XT machine. From the manual there needs to be some kind of shunt / selector in a socket to make it work on a 8 bit bus. Does a …

Mariposa SRAM Card?

VCFed about 7 months ago

Is anyone familiar with this S-100 64K SRAM card? It says "Mariposa Design Group" on the side, and has 64K of SRAM. Each SRAM has a small jumper that is labeled RA/RO (Read Only?). The center of the PCB has a set of 4 jumpers labeled X0/ …

386 DX40 Motherboard with OPTi Local Bus and 486 Socket, working. 40 Euros.

VCFed about 7 months ago

Hello. For sale here is a GMB-786UN Motherboard, 40 Euros plus postage at cost. I'm in Germany. See manual here: https://the... unusual in that it has an OPTi Loc …
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Software & Hardware • 🔨 Amiga Hardware Faults and Solutions List

LemonAmiga about 7 months ago

The Amiga is a Retro computer. Commodore built the Amiga using the cheapest parts, and the weakest solutions. The chips themselves are prone to fail. During my time with the Amiga A500, at least 1 Agnus failed, perhaps x2 CIA chips, and perhaps also Paula …

Help identifying a card for a PDP-11?

VCFed about 7 months ago

Hello all, I purchased a estate sale lot of DEC parts and boards, and was never fortunate enough to work with DEC stuff. (other than my first ISP was VMS/Vax based) I believe perhaps this is a module for a PDP-11 series microcomputer? Is it UNIBUS or Q- …
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8-bit acorn hardware • HCR Micron Plus EPROM Programmer

Stardot about 7 months ago

Hi all,I'm interested in the HCR Micron Plus EPROM Programmer, as this seems to be one of the best of the original BBC Micro EPROM programmers.It connects to the 1MHz bus and has on-board memory to allow it to deal with larger (32KB/64KB/128KB) devices. I …

Tandy 5 Meg Hard Disk

VCFed about 7 months ago

I just unearthed my Tandy 5 Meg drive, which I purchased a couple of years ago on ebay. Amazingly both the exterior and interior are immaculate, it was clearly hardly used. I also managed to buy some pure unobtanium a few months before that, an original Ta …
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8-bit acorn software: other • New key selection "dialog"

Stardot about 7 months ago

I have been asked several times about having options to change the keys in my games, but apart from Carnival which has key selection and a few others that have the option to choose from a few selections, I don't really support it.I've been thinking about …
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Prototypes of Retro-Bit's Upcoming Dreamcast Controllers Finally Revealed

The Dreamcast Junkyard about 7 months ago

Photo courtesy of SHIRO!Let's face it, the Dreamcast controller isn't exactly beloved. Sure, it was the tool that granted us the ability to experience some of the best games to ever exist, but unfortunately suffers from a not very ergonomic shape, a single …
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32-bit acorn hardware • Podule detection procedure

Stardot about 7 months ago

I'm trying to understand the Expansion card spec, and this diagram in particular from page 9:What I expected to see was that /PS is asserted during detection, and we then present our ID on to the bus as shown - notably with BD1 low to indicate 'podule pre …
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Help & Support • Pi1541 Zero with Epyx Fastload Hat Issues

Lemon64 about 7 months ago

I was wondering if anyone else had the Pi1541 cartridge model? I have not been able to get it to work. I purchased a pi zero from the pi store and it went together fine.I am using a Commodore SX64 and the cartridge/cable plug in perfectly. However, the LC …
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8-bit acorn hardware • Econet Module Extender

Stardot about 7 months ago

Yesterday I made an Econet module extender, so I can have the sockets outside the machine for swapping/testing Econet modules and components:I made it up as I went along; the original idea was to use alternate wires on a 34 way ribbon cable to connect to …
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General • Questions about JiffyDOS and/vs Action Replay 6 disk drive speed

Lemon64 about 7 months ago

I have a C64C, a 1541-II disk drive and an old Action Replay 6 cartridge.Reading up about 1541 and JiffyDOS , I understand the story goes that Commodore messed up the disk drive hardware so the C64 had to bit bang bytes onto the disk drive bus, and that J …

programming • Emulation of BBCModel B questions.

Stardot about 7 months ago

Hi guys, I have, for my amusement, started a BBC Model B emulator. I have the 6502 working, thanks for Javidx8, or One Lone Coder for his NES emulation course on youtube. I have a bus, and it handles the 64k of memory, the 16 rom slots are setup, and i …

Apple2idiot card (ESP32)

Apple Fritter about 7 months ago

While googling I ran across this.  Apparently it was introduced at KansasFest 2022 but since that always seems to be at a time I can't go, I missed it. It is an interesting and different take on interfacing an ESP32 module to an Apple II.  It uses a dua …

Check CPU & System Bus Overclocking

Mac OS9 Lives about 8 months ago

@evanboonie (over on MacRumors) https://forums.macrumors.co... is reporting the use of XLR8?s MACHspeed Control - from MacGardens (https://macintoshgarden.or... …

LED Blinkenlights and RC Networks

VCFed about 8 months ago

I'm in the process of reverse-engineering an industrial controller from the '80s that incorporates an LED-based blinkenlights operator interface, including switches for the usual interactions with the processor. It's a bit unusual in that while the system …
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8-bit acorn hardware • All dead RAM

Stardot about 8 months ago

Has anyone found a BBC B with all its RAM dead? I've been working on a particularly bad Issue 7. It took a lot of work to get the RAS and CAS working along with the address buffers not all being on at once etc. I can see the address bus reaching the RAM …
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8-bit acorn hardware • Updated Pi1MHz Hardware / Firmware

Stardot about 8 months ago

One limitation with my current Pi1MHz level shifter board is that it requires exclusive access to the 1MHz bus. If Pi1MHz is attached, then nothing else can be attached. This is not normally an issue - particularly when you've got the the level shifter pl …
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Help & Support • BASIC ROM failure?

Lemon64 about 8 months ago

I am trying to revive a 250407 with black-screen issue. No white bar.Voltages and clocks are all nominal. VIC-II is working in another mobo.Oscilloscope shows signs of address bus conflict.I thought about the usual suspect (PLA), but then I took a thermal …
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32-bit acorn hardware • 64MHz A7000+

Stardot about 8 months ago

Following on from @thecellartroll's Bush STB hacking and A7000 fixing threads, he brought me the A7000 (non-plus) board, and a Bush IBX200. "Swap the SoCs!". The standard A7000 is a 32MHz Arm7500 SoC.The A7000+ uses an Arm7500FE SoC and clocks the core …