Heathkit RX-1 Recapping

I finished "recapping", i.e. replacing the paper capacitors in the Heathkit RX-1. Some were a little tricky to get at when the unit was assembled.

Here are some of the original caps:

And here is an image after recapping (the news ones are all yellow):



I didn't notice any significant difference after recapping, but it is still a good idea to do. Depending on the circuit location, a leaky capacitor can damage a tube or other expensive component. Below is all the old caps after removal:

Heathkit RX-1 Restoration

My latest restoration project is a Heathkit RX-1 "Mohawk" Amateur Radio Receiver.

I've created YouTube video that describes it. This was Heathkit's high end amateur radio receiver of the time, with all the bells and whistles of a radio of the time. It's a large beast, weighing in at about 50 pounds.

It works, but I'm currently in the process or recapping it, to make sure that it is fully functional. I'm replacing all of the wax paper capacitors with new ones, as the original ones tend to become electrically leaky over time. This may fix the operation of the notch filter, which doesn't seem to be fully working. The circuitry around the notch filter uses a lot of paper caps.

Once that is done I will run through the alignment procedure again. As it is quite an involved procedure, that might be suitable for another YouTube video of its own.

The Visible Monitor

While waiting for my Briel Superboard III kit, I was reminded of a book that I blogged about last year. The Visible Monitor program in that book was written to run on a number of computers of the era, including the Ohio Scientific C-1P or Superboard II.

In preparation for trying it on the Superboard III, I entered the machine code from the book. Back in the day, this consisted of typing in many numbers as BASIC DATA statements. A loader program read the data at run-time and stored it in memory. A simple checksum scheme caught most errors. After a number of sessions I had all the code entered. I was able to save some time by scanning the book pages and using OCR software to convert it to text, however the process was still quite error prone and required a lot of manual corrections.

After fixing any obvious errors, I was able to load the software on an Ohio Scientific computer emulator. The loader program found a number of additional errors that I had made. After correcting those, I made a file suitable for directly loading from the OSI monitor program. Loading it into the emulator, I was pleasantly surprised to see that it ran fine. I'm quite confident that it will also run on the real hardware.

I also entered some of the source code for the monitor with suitable changes to build with the CC65 assembler. I've only entered a small portion of the code so far, and may not complete this as it is a very time consuming task. All of the code can be found here at github.

By coincidence, a lot of vintage books I recently bought on eBay included the book "Top Down Assembly Language Programming for your VIC-20 and Commodore 64". It turns out that this is essentially the same book, but with the Visible Monitor ported to the VIC-20 and Commodore 64 computers.

To be honest, the Visible Monitor seems a little clunky and hard to use and I think my JMON program is better. I plan to port it to the Superboard III.

Zenith H500 Super Trans-Oceanic

The Zenith Trans-Oceanics were an extremely popular (although expensive) series of shortwave portable radios made by Zenith from the 1940s through 1980s. I own a model H500, the most popular model of the series. Although I restored it almost 10 years ago, I finally got around to making a YouTube video about it.

On the Heathkit front, I just received two more pieces of test equipment that I will be restoring, an IG-18 Sine-Square Audio Generator and an IM-1212 Digital Multimeter. I plan to make YouTube videos about these units as well.

Ohio Scientific Superboard II

The first computer I owned was an Ohio Scientific Superboard II. Bought in 1980, it was the only reasonably complete computer on the market for under $300.

I learned a lot on that machine, including BASIC and 6502 machine and assembly language programming.

Alas, it was damaged in a flood a number of years ago and had to be thrown out. I recently found this original paperwork which came with the machine:

I am, however, eagerly waiting the Superboard III.  a replica of the Superboard II that is being offered by Briel Computers. It should be fun to see the Superboard powered up again, running BASIC and the really primitive machine language monitor. I might even have some software I wrote on old cassette tapes that can still be recovered.

I'll report back here as the project progresses.

Quick Hack: A Soldering Ventilation Fan

Here is a quick solution I put together earlier this week. The fumes from solder (more so the flux rather than lead) are not particularly healthy to breathe. I usually solder in a room with decent ventilation but I was meaning to set up some kind of fan. My quick solution was to take a small muffin fan from my junk box, glue it to a heavy block of marble I had (from some old trophies) and extend the wires to go to a bench power supply. Sitting this unit next to the soldering iron or PCB will keep the fumes away while I am hunched over a board during soldering. It only took about five minutes to throw together from junk parts I had lying around.

Can Heathkit Make a Comeback? Yes, and Here's 10 Reasons Why.

Despite all the reasons I listed in my last blog post on why Heathkit could not successfully reenter the kit business today, I believe they still can. Here are some reasons why, and how, they could do it.

1. Reinvent yourself. Heathkit started as an airplane manufacturer, then got into aviation electronics. Then test equipment, amateur radio, audio, and computers. The company twice lost their president in airplane crashes and had to reinvent itself. The new Heathkit could and probably should be different from the Heathkit during the heyday of the past. There are many opportunities for products different from those that Heathkit traditionally offered. They need to think outside the box and come up with new ideas for product opportunities.

2. Leverage the Internet. The Internet means there is no longer a need for brick and mortar stores. No printed catalogues or advertising. The Internet means global markets. To be successful, Heathkit needs to adapt to the times. As just one example, the large effort to write assembly manuals could be crowdsourced by allowing users to edit and improve the manuals, much like Wikipedia. Support for building kits could be handled by on-line forums. People who are active in helping others in the forums could be rewarded with some type of badges, promotional items, or discounts on kits.

3. Buy some expertise. Buy out or recruit some successful small kit companies, like Briel Computers, for example, or license their designs. Expand them in size to offer better ordering, distribution, manuals, and packaging than a one person outfit can handle.

4. Fill a size niche. I think there is a gap between the small one-person companies and the large electronics firms that Heathkit could fill and be successful while still remaining small and lean.

5. Crowdfund startup costs. Get initial funding using sites like Kickstarter and Indiegogo. Take one good idea, maybe a new solid-state ham radio transceiver like a redesigned HW-8, that is internally a new design but has the original retro look. Fund the cost of getting it to market and get initial orders using crowdfunding. That revenue could then fund R&D for future products.

6. Steal ideas from successful competitors. The experts said you couldn't offer a kit that competed with commercial amateur radio equipment for price and features. Elecraft did it. They said the market for hobbyists is too small? AdaFruit is doing okay. Learn from the successes of competitors and adopt ideas that worked for them.

7. Partner and contract out. Sell through Amazon. Have someone else do kitting. Avoid the need for a big factory and inventory. Run the company as a virtual distributed organization with staff located world-wide.

8. Link it to education. There is a huge demand for learning materials for electronics hardware and software, as evidenced by products like the Arduino and Raspberry Pi. Leverage Heathkit's expertise in developing training materials and courses (one of the last areas where they were successful).

9. Capitalize on nostalgia. Offer some of the original kits again, even if only on the outside. Consider offering some vacuum tube designs. Make the assembly manuals look like the old ones, possibly offering a printed manual (rather than download) as an extra option when ordering a kit.

10. Build credibility and reward early adopters. Lots of people would like to see Heathkit succeed. Offer incentives to people who pre-order. Reward early purchasers and they will give you free marketing. Be open about plans for the future, and the keep promises you make. As just one example, why not make the legacy Heathkit manuals available as free downloads as a goodwill gesture and a sign that Heathkit is serious about coming back?

In summary, I believe Heathkit could re-enter the kit business if they adopt some of the ideas I've outlined here. It won't be easy, and the clock is ticking as the old Heathkit becomes a faded memory, but it can be done.