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#1
09-18-2005, 05:53 PM
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yard sale non-score :-( Heathkit GR-78
Some 'round the corner neighbors had a barn sale a few months ago. Bought a nice pair of EPI 100's for $15 but passed on a pretty SS Heathkit GR-78 multiband receiver at $40. Wellp, those folks opened their barn again on Saturday... the GR78 was still there, and (with assurances from its owners wife that it worked), I bought it.
Wellp... it does look very nice, but it doesn't seem to be receiving. I do get some AC buzz (like motor/fluorescent lamp ballast buzz) midscale on the "A" band, and some clicks 'n' pops bandswitching, and even some bleedover (sounds like overmodulated, clipped CB from somewhere) here and there on other bands. "S" meter goes up to about 3 or 4 upon turn-on, and not too much else happens. Everything goes quiet (and, of course, doesn't light) if I push the "light" momentary-contact switch. Did I waste $40? Any words of encouragement are appreciated. It IS pretty, isn't it? :-)
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all the best, mrh 
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#2
09-18-2005, 07:07 PM
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Did you get a manual? If not there's one here: GR-78
It probably worked last time it was turned on... I'd suspect the electrolytic caps first... Heath was known for using the cheapest components available. Were you using the whip antenna or a longer wire? $40 is a typical eBay price...
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#3
09-18-2005, 07:48 PM
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Nope, no manual. Thanks v. much for the BAMA link... I hadn't checked there yet (been busy today). The P/S is quiet, but i am sure there are plenty of other 'lytics in there, eh?
I really just tried the whip, though I did fiddle at the EXT input with a clip lead, jes' looking for some life. I assume there's no ferrite rod ant for BC?
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all the best, mrh
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#4
09-18-2005, 07:52 PM
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Mark:
I had to chuckle. I picked up a GR-64 off the curb Friday, hoping that there'd be some nice tubes inside. No such luck, but after cooking the caps in that Telefunken a few weeks back, this one will go on the variac for a few days before it gets a full test. Now those two Telefunken 12AX7s in the Bogen Challenger that was next to it were a sweet find though  
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I think the world is run by "C" students - Al McGuire
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#5
09-18-2005, 11:06 PM
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The difference in reception with and without a good earth ground on a sw radio receiver is startling... even using a whip on the ant terminal... that ground makes a HUGE difference... I have experienced it before, as recently as this year when I sold a triple conversion superhet panasonic....
without it almost nothing even with strong local stations, but when I tapped into the ground wire coming from my 8' stake... whoahhhh.... The ground on an outlet (use the plate screw, but test everything first as to hot etc miswiring) can make do... (my house antenna coax is bonded to the rod, and seperate from the ac power ground.) also: did you fiddle with the rf gain??? in the picture, it's at minimum.
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 Nothing is ever completely fool proof, because fools are so ingenious. Last edited by markthefixer; 09-19-2005 at 02:21 AM.
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#6
09-19-2005, 08:09 AM
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Will try 'earthing' her tonight.
Yup, tried the RF gain at min, mid, and max. I like to be cautious with the front ends, until I start getting frustrated! :-)
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all the best, mrh
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#7
12-23-2005, 08:45 AM
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Just stumbled across this old thread, and thought I'd provide an update FWIW. The problem with the GR-78 turned out to be nothing more than its completely discharged NiCd battery! I left it plugged in for a while, and it worked when I turned it on! It's working fine at this point. It's a cute little radio, with a lot of stuff inside it.
I did pick up the manual from BAMA, BTW.
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all the best, mrh
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