New Project – Heathkit GR 2501 Color TV Kit

Straying still farther from the core focus of building vacuum tube-based amplifiers, this project is mostly for nostalgia. Awhile back on eBay I found an ad for an unbuilt Heathkit GR 2501 color television set. This was too good to pass up. So, I placed a bid, expecting to be outbid by hundreds of dollars. Much to my surprise, I won the auction.

This page documents the construction process, from unpacking the boxes to placing the TV set in service.

This project has a very long time line. As explained in the following storyline, the initial work focused on checking the condition of the kit. Step two was to seal up the boxes and put the kit aside until Christmas, when the kids would wrap up one of the five boxes (the small one) and give it to me as a present. I reasoned that the week just after Christmas would be a good time to start this project, as I would very likely be on vacation.

A description of the GR 2501 from the Heathkit catalog (#864, Winter 1983-84) is shown on the right. You will note that this kit is sold with the major circuit boards factory-assembled. Initially I was disappointed that I would not be building up the TV set from a pile of parts. After some reflection, however, this is probably a very good idea. The circuit boards are complex and some boards require careful alignment using specialized test equipment. I have come to appreciate the wisdom of Heathkit in taking this approach.

Upon completion of this project, I plan on integrating the TV set, a turntable, the Ampex 1455 tape recorder, AM/FM stereo tuner, stereo preamp, 40 W stereo power amplifier, and speakers into a console stereo system. The console stereo was, of course, a popular feature of countless 1960s living rooms.

Catalog description of GR 2501


I built my first Heathkit in about 1965. It was a vacuum tube volt meter. When the company started offering TV set kits for sale, I very much wanted one. It would be the ultimate kit-building challenge. Unfortunately, the TV kits retailed for about $650, which was way outside my price range as a college student. Later on, there were always higher priorities. Anyway, when the GR 2501 kit came up on eBay, I couldn't resist.

The GR 2501 is, of course, built to receive NTSC signals, and broadcasters switched off their NTSC transmitters years ago in the transition to digital TV (DTV). The solution is simple, however; a DTV converter box. A converter can be easily found. Most are reasonably priced and perform quite well.

GR 2501 boxes

When the boxes arrived (there were five in all), I was pleased to see they were the original Heathkit boxes. Furthermore, most of the boxes containing the major sub-assemblies were still sealed.

The five boxes were organized as follows: CRT, mechanical supports and trim pieces, cabinet, electronic components and circuit boards, and Space Phone option.

All boxes were in good shape, having survived remarkably well over the past 30 years.

Picture tube in box

The Space Phone option allows the consumer to use the TV set as a telephone. Perhaps not the best marketing idea ever, but you've got to give Heathkit credit for thinking outside the box, so to speak.

Update 1 (August 1, 2013)

The circuit board and components for the Space Phone were packaged with a piece of foam rubber for protection during shipping. Unfortunately, foam rubber does not last forever (or at least the type used in the 1980s). The foam rubber in the box had quite literally disintegrated into mass of black gunk. Fortunately, most of the debris could be blown out with compressed air. A considerable amount, however, adhered to the component and foil sides of the circuit board.

Flux remover and a brush did a good job of cleaning the board. It was a messy and unpleasant job. The end result, however, was quite good. The cleaned board looks like new.

Having dealt with one piece of foam rubber, I was concerned that the same material had been used elsewhere in the kit. So, I opened all of the boxes to inspect the condition of the packing material, and the contents themselves. Of the 10 or so sealed boxes, only one additional box had the foam rubber packing material. It too had disintegrated. Here again, the contents were cleaned and returned to new condition.

Each of the boards for the GR 2501 are shown below. As you can see, they all look very good.

IF processing board

Shown on the left is the IF processing board. On the right is the color processing board.

Color processing board
Deflection processing board

Shown on the left is the deflection processing board. On the right is the high voltage and horizontal output board.

High voltage and horizontal output board
Video driver board

Shown on the left is the video driver board. On the right is the Space Phone accessory board.

Space Phone board

Update 2 (August 3, 2013)

Having checked (and cleaned, as necessary) all elements of the kit, the boxes have been re-sealed and placed in a safe location. The current plan is to come back to this project after I receive it as a "Christmas present". I love surprises...

Update 3 (August 9, 2013)

I came upon the catalog description of the GR 2501 (1984). That text is reproduced in part below.

"High-fidelity picture sharpness is yours with a Peak Resolution Picture circuit that achieves 25% greater detail than ordinary TV by reproducing up to 330 lines of broadcast resolution. The included comb filter eliminates vibrating, spurious color and makes picture detail pop out sharp and clear for a lifelike degree of clarity found previously only in the most expensive professional-quality video monitors. The tri-focus picture tube has three concentrated focusing actions instead of just one—for cleaner, brighter images.

Like a chromatic control center in your TV set, the sophisticated Color Sentry combines eight automatic picture and color sub-systems for magnificent viewing pleasure. It maintains accurate color level, life-like flesh tones, tint and contrast—it even adjusts the picture brightness as the surrounding room lighting changes. To maintain the GR 2501’s outstanding picture fidelity over time, an Automatic Color Clarifier circuit removes any magnetism in the picture tube that may cause noticeable color impurity each time the TV is turned on from a cold start. A sharpness control lets you adjust the GR 2501's level of picture definition. Advanced digital circuits scan and lock on to the broadcast signal, eliminating any kind of vertical- and horizontal-hold control. Altogether, the most impressive picture you can build.

A no-wear quartz PLL varactor electronic tuning system seeks out and fine-tunes the exact station frequency. Because the tuners are electronic, they have no moving parts to corrode, erode, or cause noisy picture problems. Solid-state automatic fringe-lock circuitry provides unshakable picture stability on fringe area reception, while a phase-locked AFC pulls-in off-frequency signals from cable or master antenna systems and video games.

A power-sensing voltage regulator helps conserve energy by supplying only the power needed by the TV and maintaining a stable chassis voltage. Electronically self-regulating, it virtually eliminates the effects of household line variations and provides a more constant voltage for improved component and picture tube life.

Your new GR 2501 comes with our Computer Space Command remote control for scanned or direct-access channel selection, on/off, variable volume, on-screen display of channel with current time, plus on-screen check or activation of the preset Time Control Programmer feature and Advanced Space Phone features. An easy-to-read on-screen channel/time display appears briefly when channels are changed, or recalled from set or remote control. Expanded 112-channel tuning capability lets you select from up to 42 cable offerings as easily as VHF and UHF, except for scrambled premium services.

A convenient audio output jack can interface the TV sound to an auxiliary input of your personal stereo system for clearly-amplified sound reproduction. The 100% modular chassis design of the GR 2501 guarantees outstanding reliability by using fewer interconnections, with all modules factory pretested and aligned.

With Advanced Space Phone you can take or make calls anywhere in the world. A dialed number prints out on the TV screen, and in case you get a busy signal you can even program the remote to redial automatically. The TV set itself is readily connected to any telephone line to work as a sensitive speaker phone, so you don’t have to leave your easy chair, and the whole family can participate in the conversation."