bc-22e ww2 reciever operating in a hotel

Dodgy Hotel, Beer And A WWII Era Tube Receiver

May 23, 2014 by Will Sweatman 21 Comments

In the luxurious accommodations provided by Motel 8 and armed only with a few tools and a six pack – a pair of amateur radio enthusiasts attempted the repair of an old WWII era BC-224E receiver. They picked up the ~~boat anchor~~ antique receiver, which was in unknown condition, from a flea market while in town for the Dayton Hamvention, brought it back to their hotel and got to work.

The BC-224E came in two parts – the receiver and the power supply. The speaker for the system, which is actually located in the power supply, is driven by a large inductor. Apparently when the receiver was constructed, the permanent magnets of the day were not powerful enough to drive a speaker.

Fortunately, the receiver also came with some schematics, allowing [Gregory] and his fellow radio enthusiast to reverse engineer the power supply. After a few tweaks and cap swaps, they crossed their fingers and plugged it in. Stay tuned to see what happened next.

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Sinclair ZX Spectrum +2A Slims Down

May 21, 2014 by Adam Fabio 37 Comments

sinclair

[Carl] got his hands on a dead Sinclair ZX Spectrum +2A. He decided he wasn’t just going to fix it, he was going to improve it! The ZX Spectrum Compact is literally a “sawn-off” Spectrum +2A. [Carl’s] inspiration came from a similar mod at the Old Machinery blog.

Amstrad seems to have had a habit of bolting on additions to their products. In the case of the Spectrum +2A, it was a tape drive. Tapes weren’t a great storage method in the 80’s, and today they’re downright annoying. [Carl] didn’t need the tape interface, as he’s using a DiVide ATA interface.

The modification is rather straight forward. [Carl] broke out the hacksaw and cut the right end cap away from the tape drive. He then cut the entire tape drive away. The motherboard wasn’t safe from the saw treatment either, as the printer interface was cut off. Thankfully there were no components on the printer interface. Apparently [Carl] didn’t short any traces as he went to town with his saw.

With the motherboard modified to fit the abbreviated case, [Carl] was ready to begin reconstruction. He glued the cap onto the sawn-off case with Grip Fill glue, which also served to fill any gaps. Some sanding, priming, and painting later, The ZX Spectrum Compact was finished. This isn’t a perfect mod, as the gap is still slightly visible under the paint – but it’s good enough for [Carl]. Hey, it’s good enough for us, too – we can’t all be [Ben Heck]!

Emulating Touchscreens In Python

May 18, 2014 by Brian Benchoff 11 Comments

DOS

Software, especially DOS-based software meant for CNC control lasts forever, but hardware most certainly does not. When faced with aged and decrepit hardware meant for controlling a CNC machine that was slowly dying, [Oliver] needed something that would emulate 3M Microtouch touchscreen. Not wanting to go the hardware route, he decided to emulate a touch screen in Python.

The Python code is fairly simple, taking mouse input and translating it to the serial protocol the 3M Microtouch, and thus the old DOS CNC app, uses. Writing the Python to capture mouse clicks was only half of the problem, though. [Oliver] also needed a way to send these mouse clicks to an old DOS application. Virtualizing an old machine running DOS created a few timing problems, but a solution was eventually found with DOSBox and the Virtual Serial Port Emulator that can connect two applications with serial ports.

[Oliver] was finally able to get everything working, bringing this equipment back to life for at least another 30 years. Let’s just hope all the code is well documented and archived for the next guy.

NYC Resistor Gets A PDP-11/34

May 18, 2014 by Adam Fabio 40 Comments

PDP-11/34 NYCR

[Trammel Hudson] and NYC Resistor have gotten their hands on some old computing iron in the form of a PDP-11/34. The PDP-11 is a 16 bit minicomputer made by Digital Equipment Corporation (DEC). Various incarnations of the PDP-11 were sold from the 1970’s all the way into the 1990’s. NYC Resistor’s model is has a label dating it to 1983.

The PDP was found in an old storage unit in the Bronx. Moving several racks of equipment across the city is no small feat, but NYC Resistor members have it done it so many times they’ve got it down to a science.

Once power is applied, a stock PDP won’t actually do anything until the boot loader is keyed in from the CPU front panel. Thankfully this particular PDP-11 had its boot instructions printed on a label on the CPU. NYCR’s machine also includes an M9312 “bootstrap / Unibus terminator” board, which allows the machine to boot at the push of a button.

The team connected the racks, terminals, and drives. Carefully following the instructions, they actually got their PDP to boot up! Their next step is to start reading in some of the old tapes that came with the machine. We’re all waiting with bated breath to see what “digitized monkey brains” contains. Once the machine is fully functional, we hope they get it on the internet and load up The Hackaday Retro Edition.

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Johnny Mnemonic, Broken Columns, And Pinball Repair

May 17, 2014 by Brian Benchoff 13 Comments

johnny

[Quinn Dunki] has come to realize the pinball machines of her youth aren’t the lame games she remembered. They’re actually quite marvelous in terms of electronics, mechanics, engineering and the all important hackability. Wanting to pick up a 90s dot matrix display pinball machine and being a [William Gibson] fan, [Quinn] picked up an old Johnny Mnemonic machine. She’s already looked into replacing the incandescent bulbs with LEDs, and has just wrapped up troubleshooting a broken plasma dot matrix display.

dots The neon dot matrix displays in pinball machines of this era are finicky devices with a lot of stuff that can go wrong. On powering the display up, [Quinn] noticed a few columns on the left side of the display weren’t working. These machines have great diagnostic menus, so running a test that displays a single column at a time revealed two broken columns. However, when a solid fill test was run, all the columns work, save for a few dots in the upper left corner. This is an odd problem to troubleshoot, but after more tests [Quinn] realized dots in column five and six only work iff both adjacent dots in the same row are lit.

The power supply seemed okay, leaving the problem to either a logic problem, or something wrong in the glass. With a meter, [Quinn] deduced there was a short between the two broken columns, and tracing every thing out revealed a problem in the hermetically sealed display filled with noble gasses. A replacement display was ordered.

While [Quinn] was replacing the display, she decided it would be a good time to rehab the almost-but-not-quite out of spec driver board for the display. The power resistors had scorched the PCB, but didn’t damage any traces. Replacing the parts with modern components with a higher power rating brought the board back to spec with components that should last longer than the 20-year-old parts previously inhabiting the driver board.

It was a lot of effort, but now [Quinn] has a brand new display for her pinball machine and is ready to move on to the next phase of her restoration.

C64 MIDI And Flash Cart

April 30, 2014 by Brian Benchoff 12 Comments

Kerberos The SID chip inside the Commodore 64 and 128 is arguably still the gold standard for chip tunes, and the C64 itself still a decent computer for MIDI sequencing. [Frank Buss] realized most of the MIDI cartridges for the Commodore computers are either out of production or severely limited, so he set out to create his own.

Unlike the few Commodore MIDI cartridges that are available, [Frank]’s Kerberos has MIDI In, Out, and Thru, controlled by the 6850 ACIA chip, just like the old 80s interfaces. This allows the Kerberos to interface with the old Sequential Circuits, Passport, and Datel software. He’s offering the Kerberos cart up on a crowdfunding site, so if you’d like to grab your own, have at it.

Because the Kerberos is also a Flash cart, it also ships with some of this software; [Frank] got permission from Steinberg to install their Pro 16 software with the Kerberos. SID Wizard is also pre-loaded on the cart, along with a few other fabulous trackers and sequencers. Of course, there’s no requirement for the Flash portion of the cart to only host MIDI and synth software. You can always upload a few games to the cart over a MIDI interface. Video of the Kerberos below.

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Hackaday Retro Edition: Hackadaying At 300 Baud

April 27, 2014 by Brian Benchoff 16 Comments

SONY DSC

For a bottom of the barrel website like our retro edition, there’s little reason to have a fast Internet connection. Even the fastest hands in the land can barely type faster than 300 baud. The problem with low-speed connections is the overhead involved, as [Pierre] discovered when he dug out an acoustic modem from the ’80s and loaded up our retro site.

While this isn’t the first modem ever made – that’s 1960s tech – but it does operate at the same speed – 300 bits per second, or slower than you reading this sentence. [Pierre] stuck a desk phone into the modem’s cups, plugged it in to a phone line simulator, and connected to a Raspberry Pi equipped with another modem. From there, it was pretty easy to set up a terminal at 300 baud.

A serial connection isn’t a connection to the Internet, however, and at 300 baud, PPP is nearly impossible. The overhead of encapsulating packets is just that high. SLIP is a much better choice to send IP packets over a slow serial connection, but [Pierre]’s mac doesn’t include the proper tools.

[Pierre] ended up using the serial connection between his Mac and Raspi with Zterm. From there, Lynx and Bob’s your uncle.

There’s an unsurprisingly long video of [Pierre] loading up the retro site below, as well an unsurprisingly long video of speedtest.net running at 56k.

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