The Heathkit GR-78: Ed’s “basket case” radio

BasketcaseMany thanks to SWLing Post reader, Edward Ganshirt, who writes:

I picked up this Heathkit GR-78 at a estate/moving sale. It was in a pile of “e-waste” (you know, old vcr’s broken TVs, remote controllers, dead cell phones, etc.).

I found a container and sorted through the stuff to retrieve all what looks like Heathkit parts. The radio was disassembled and scattered about. I was able to collect all the critical components and brought the works to the sales table. The person manning the table said that was stuff they were discarding and I could have it for free but the Easter basket was $0.50.

So far I had put little time into it but was able to mechanically assemble it completely. All the fasteners holding the cabinet were missing. The rest appears to be all there but the primary side of the transformer is open and the NiCads are shorted and stone dead. The manual that I found in their recycle bin is complete and appears to gone through 3 owners by 3 sets of handwriting in the notes and comments through out the manual. If anything this looks like a CSI/forensics troubleshooting process getting into the mind of 3 different owners unsuccessful at making it work.

I will keep you posted on the progress.

WA1-LAI

More power to you, Ed! There are few things as difficult as picking up where someone else left off on a kit build. Your project is exponentially more complicated since there were three people involved and parts are scattered.  Please update us with your progress.

Readers: If you have any experience with the GR-78, I’m sure Ed would welcome your input!

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8 thoughts on “The Heathkit GR-78: Ed’s “basket case” radio

  1. Michael Collins

    I have been given a HEATHKIT GR-78 by my Sis- in-Law which belonged to her late husband. I know nothing about Radios or Ham equipment. there are no leads/connections with it and the Band Spread dial doesn’t seem to move properly. Would this be of use to anyone. I love in Hamilton, Ontario, do you have any contacts in the vicinity who could do anything with it?

    Reply
  2. Jim Talt

    I just got one of these off Shopgoodwill.com. It was intact except no battery but otherwise in good condition. I pondered and then decided to make it a usable receiver for the 21th century. As you probably know this unit is designed to run from the battery. The AC connection is only to recharge the battery and came with a warning not to overcharge. I carefully removed the AC xfmr, diodes, regulator lamp, terminal strip, AC connector and dc connector as a “unit” with all wiring intact. Using the existing chassis mounting holes I installed a SPDT switch where the AC plug used to be and a wall wart style K size dc connector where the orginal dc connector was mounted (plastic adapter plates were used on both locations so the existing chassis holes could be used. ) The switch toggles between the new DC connector and a standard 8 AA cell battery holder now mounted inside. The common pole is connected to a fixed 10V regulator pcb mounted on the back plane and has two taps: One tap drives the audio ckts directly, and the other tap drives all the other circuits through a 15 ohm dropping resistor. The unit had a short somewhere so I replaced/shotgunned all the electrolytics without further investigation (though I merely clipped out the big filter cap that was no longer needed). The unit worked after that. I did find that alignment without test instruments was iffy. I did it that way per the manual and thought it was aligned. Then I did it with counters and signal generators and found that my earlier alignment was waaaay off. Anyway, it works great and I’m having fun with it.

    Reply
  3. Ken Carr

    Great story and well worth followups.
    Suggestion: any readers who have a working example of this radio might want to offer some help to Ed. I have found that a complete series of photographs inside and out is often useful for getting things right.

    Reply
  4. 13dka

    Alas I don’t have experience with assembling the GR-78, I just bought a finished kit back in the early 80s and used it for a while, it was also my first own receiver with SSB. IIRC (mind you, that was 30+ years ago!) it performed fairly well on the BC band and AM shortwave up to 25m and I logged quite a few stations with it. On SSB it suffered from the fiddly tuning even with the bandspread dial (I even mounted a geared knob but it didn’t help much), it generally didn’t work very well on the higher bands in terms of sensitivity, the simple BFO design didn’t allow for choosing a sideband and the frequency stability left a lot to desire.

    Reply
  5. Ed McCorry (KI4QDE)

    Wow, good luck with the rebuild/repair or whatever you have to do with it. The good thing is that it’s a Heathkit so at least you have good documentation.

    Reply
  6. Moshe Ze'ev Zaharia

    Good luck with this challenge, hope you got all the parts.
    At least the dial string looks intact. 50c for the basket? what a rip off! (;

    Best Regards,
    Moshe.

    Reply

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