Grunow model 1191

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Grunow model 1191

Post by Wildcat445 on Mon Aug 19, 2013 5:34 pm

The radio that is in my avatar is a Grunow 1191 that my grandmother got for Christmas in 1936. It was struck by lightning in the early 1950's and sat in a back bedroom of her house for as long as I could remember. I always wanted her to have it repaired, but she claimed that it was not repairable. She had a flower pot sitting on top of it, so the veneer was ruined on the top of the cabinet. I asked her one day if I could have the old Grunow. She finally gave it to me before she passed away. It was my first radio. It is the radio that started my radio hobby. I got it working and refinished the cabinet. It is an 11 tube radio with P-P audio, but it has never been a terribly good performer. I certainly have "lesser" radios that perform as well, or better, than this one. After I posted my avatar, I decided to plug it in to see if it still worked. I had not done so in over ten years. The short answer is "kinda." It "powers up", no smoke, but also no stations come in. The dial drive belt is broken, again, for the umpteenth time. The problem that put it in the bedroom in the first place is that lightning ruined the antenna coil. I got a new coil and installed it, but it has never seemed to track properly. Or at least I can't get it to track properly. This radio has always had weaker audio than I would like and its sensitivity has not been terribly good. I aligned it when I got it running nearly 40 years ago, but perhaps my skills have improved sufficiently that I could now do an alignment and improve matters. It still has the original 6F6G ouptut tubes. I normally sub the 6F6 tubes for 6V6. I feel the 6V6 tubes work better. That may be all in my head, though. I redid the cabinet in the late 1990's and used polyurethane on the cabinet. That was also my first use of poly on radio cabinets. I like poly, use it almost exclusively. I do not want to start a war here about poly. I understand the objections people have to using it. I only mention it because this cabinet does not look "plasticky" or too glossy, which is the normal gripe about poly. Enough on that subject.

I am going to pull the chassis and speaker out of this radio and go through it again. I would bet that I did not replace the filter caps when I got it running all those years ago. My service notes do not indicate otherwise. I have a 3x5 card file with a card for each radio in my collection. Every record player, and all the other odds and ends that I have collected over the years. Whenever I perform service on any one of them, I update the card so that I can use that for future reference. Why not do this on a computer? Why? My antiquated system works just fine, is simple, the hard drive will not crash, and I understand how to use it. I am too old to mess with progress, I reckon. I will do a complete recap and alignment. Probably will find some resistors out of tolerence, too. I don't know why I haven't played this radio in so many years. I have a Zenith 5S56 sitting fairly close to it and I haven't fired it up in awhile, either. It is a fairly miserable radio, only five tubes, but was my dad's milkhouse radio when I was a kid. He used the top rail of his Red Brand fence as an antenna. I have spent many happy childhood hours out in the milkhouse with dad and grandpa milking cows and all of us listening to the Grand Old Opry on that old Zenith radio. I have a Truetone D-925 that sits a lot as well. It belonged to my grandmothers cousin who loved the Chicago Cubs. I remember him in his rocking chair on their screened in porch listening to a Cubs game on that radio. These radios are early ones in my collection, and my interest may have been divided enough so that they kinda got the short shrift along the way. That old Truetone is a good performer, and my notes indicate that all that has been done to it is to clean it up, test the tubes, refinish the cabinet and put in new grill cloth. May be time for a recap on it as well. These three old sets may be my next projects. I will start with the Grunow and go from there.

Regards

WC

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Re: Grunow model 1191

Post by mr_ed01 on Mon Aug 19, 2013 7:47 pm

Check closely the contacts on the band switch, mine had a burned contact connecting to the broadcast band antenna coil.

If yours has the original power transformer, consider using the 125V tap, (brown lead) instead of the 115V tap (green lead). The transformer runs cooler using this tap.

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Re: Grunow model 1191

Post by Wildcat445 on Mon Aug 19, 2013 8:16 pm

Thanks for the tips. Mine is original as far as I know concerning the power transformer. My line voltage here hovers around the 115 to 118 volt range. Yesterday, the voltage was 117.4 at one point. I will check and clean the band switch, per your suggestion. Thank you for your input.

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WC

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Re: Grunow model 1191

Post by 75X11 on Mon Aug 19, 2013 8:28 pm

Good looking radio. I'll bet it'll sound good too!
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Re: Grunow model 1191

Post by Wildcat445 on Mon Aug 19, 2013 9:02 pm

I have an RCA 75X11 like in your avatar. I have a 75X16, too. My wife has cabbaged onto them, since they have been classified as "cute." I exercised all my best words trying to get the chassis out of my X11 for the first time. They are good performers for being AA5's. My wife collects "cute" radios and I just collect "old crap." Her terminology, not mine. We all have our standards, I guess. The Grunow should really sound better than it does. The Crosley 170 that I just finished is 10 tubes and a 9" speaker and it sounds and performs better than the 11 tube Grunow with a 12" speaker. That should not happen to my way of thinking. Thanks for the good words about the old Grunow.

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WC

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Re: Grunow model 1191

Post by Wildcat445 on Wed Aug 28, 2013 9:33 pm

I have removed the chassis from this Grunow, and have it on my bench. It appears to have been partially recapped at some point. The filter caps have been changed, but that may have been 40 years ago. The dial belt is a rubber O-ring that I put on and it is busted. I may spring for a real dial drive belt, if I can find one. The chassis on this radio is ultra-nice, and has my grandfathers name and phone number written in pencil on the back edge. I am going to test the tubes, replace the 6F6G output tubes with a pair of 6V6G's that I have. A good tune-up and cleaning should put this thing back into operation. A good alignment will not hurt, either.

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WC

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Re: Grunow model 1191

Post by Wildcat445 on Wed Sep 18, 2013 11:45 am

The 11 tube chassis in this radio should perform lots better than it does. It has a tuned RF stage and three stages of IF, but I have AA5's that are more sensitive that this. The volume is low and the bass sounds strangled. I get nothing if it is not hooked to my outside antenna. Most radios will operate in the house with a short chunk of hookup wire for an antenna. I need to start over and see what ails this radio. It needs more than a tune-up.

I started by going over the basics. I replaced all the coupling caps and the filter caps. I tested all the tubes, and replaced the 5Z3 rectifier. I may return it to service, but it tested sufficiently weak that I replaced it during testing. I always figured that if the filament lit in a rectifier, that it would work okay. This set may be the exception to that rule. I applied power again and started checking voltage at the various tube elements. The only voltages that were correct were in the power supply, basically anything following the output filter cap was out of spec. I won't list them individually, but suffice it to say that I had found the problem. I started checking resistors. Yeah, I know, EVERYBODY checks them during a recap. Not me. I like doing the same thing twice, I guess. Again, I won't list them individually, but there are enough out of spec, LOTS out of spec, that I have decided to replace every resistor in the set. I am going to leave the mica caps alone at this point. One resistor measured almost double what it was rated. This radio just may have had a little hack work done at some point. I found a couple of globby solder joints. There is a mixture of dog bone and carbon resistors in this radio. I find out of tolerance resistors from time to time, but I have never worked on a radio where so many resistors were so far out, mostly drifted high. Wonder could that lightning strike 60 years ago had some effect on that? I have ordered a kit of resistors, and, when it arrives, I will go from here. BTW, per an earlier suggestion, I checked and cleaned the band switch. It seems to be okay at this point.

Regards

WC

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Re: Grunow model 1191

Post by willy3486 on Wed Sep 18, 2013 5:16 pm

I use to have a Grisgby Grunow years ago. It was one of my favorites but it was missing some of the dial parts, it was a pushbutton type round dial. I basically gave it away. I was needing to weed out as I didn't have my storage area anymore. I wish I could find one like it, the thing played extremely well.

As far as poly I do have a question. Is this the polycrylic stuff? I like you really like it. Years ago I tried it and like the ease of cleanup and no fumes. I found a trick to use it that works wonders. After my first coat I will finish it out the same way I did when I painted a few of my cars. I would wet sand it slightly with a high grit, at least 600 to 800 grit. I then wiped it down and recoated it. I would do this until I liked the finish, usually 3 to 4 coats. To me it can be as nice as any other finish. I have some to redo and I may use poly as well. I say fix it the way you want, its yours. Anyway its a nice radio.

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Re: Grunow model 1191

Post by Wildcat445 on Wed Sep 18, 2013 8:58 pm

Thanks, Willy. I got started using urethanes while I was in the auto restoration business. The ModelA/Model T guys griped about using poly much the same as the ARF guys do using it on radios! But try to find a Model A or Model T that has been done recently that does not have urethane paint. Polyurethane in all versions is so much superior in every way to lacquer. Lacquer is old technology. And, it is becoming harder to find due to its environmental impact. Not learning to use poly and clinging to the old way of doing things just because that is the way it has always been done is silly as far as I am concerned. We rebuild our radios using modern components, why not treat the cabinet to the same advantages?

I typically put from 12 to 15 dust coats on a cabinet. I will spray three coats, let it dry for 72 hours or so, wet sand with 1000 grit, and repeat the process until I am happy with how it looks. I don't get all excited about toners, since my wife says that cabinets with toners look like the toner is used to cover up a defect, and that it detracts from the wood. She may have a point. Toners were sometimes used to hid end grain that there are procedures nowadays to handle. The only toners I use are to indeed cover up a defect, or if it still on the cabinet after I use refinisher on it. That Grunow cabinet was sprayed in a spray booth by the man who used to paint cars for me. That is just clear, semi-gloss Minwax polyurethane. Grain filler is unheard of and unavailable around here (like turbine oil!) so I use shellac for grain filler. I put on from 3 to 5 wash coats of shellac, block sanded with 600 grit between coats. Shellac also works as a sealer and will not lift using either lacquer or poly. We have cats and the wife has flower pots. Poly makes wood impervious to the ravages of both. Lacquer will not stretch or shrink. It splits and falls off. Poly will move with the wood. The only downside I have seen to poly is that if you do not clean your spray equipment really well, you need new spray equipment. Acetone will cut cured poly, in spray equipmnent, but not very well. I messed up one time and had to redo a cabinet done in poly. Paint and poly remover did the trick with not much more trouble than my homemade concoction does on lacquer. The problem people run into using poly is that they use gloss material. Unless you want a piano finish, it is really too shiny. I think this is what the radio purists and snobs get their nose up about. It is like anything else, it will work well once you learn to use the correct product the way it was inteded to be used. Sanding will dull it and polishing will brighten it, making the "too glossy" argument doubly moot. To each his own though.

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WC

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Re: Grunow model 1191

Post by willy3486 on Wed Sep 18, 2013 9:09 pm

I got sold on the polly about 10 years ago. I was laid off at the time and had little money for presents so I made my wife and daughter stand up jewelry cabinets. I got a quart of polycrylic to put on it since it said low odor and easy cleanup. I brushed it on and I did not like the coat. I thought I would wetsand it lightly then rebrush it. Then when I rebrushed it I really liked the looks, so I thought I would wet sand it again. After doing that 3 or 4 times the finish was better than any finish I had ever done. So from then on I have only used polycrylic. I haven't done a radio yet but I plan to. I just got to get the time to fix one. As far as radios goes I remember what one old man said on tv. He was on a show where they show artist or interesting people. He was probably in his 80s. He said there was some in the radio field that did not like radios unless they were "perfect" by their rules. He said I am not fixing the radios for them I am fixing them for me. That impressed me. Thats about how I feel. So my opinion is if someone wants to do it a one way and they are happy then thats great .

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Re: Grunow model 1191

Post by 75X11 on Wed Sep 18, 2013 9:33 pm

I wish I could do refinishing as well as your avatar shows. I can do metal and plastic, but anything broader than the stock for a rifle or shotgun is beyond my ability. Well finished wood is a thing of beauty.
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Re: Grunow model 1191

Post by Wildcat445 on Wed Sep 18, 2013 10:04 pm

I have tried brushing poly on and I can't seem to do it right. It dries too fast and ends up streaky. It takes a lot of sanding to get the streaks out. You notice I mentioned having to strip and redo a job done in poly. I had brushed it on. For small jobs, not large enough to get out spray equipment, I just buy a spray bomb of poly and go to it. I congratulate you on obtaining good results using a brush.

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WC

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Re: Grunow model 1191

Post by willy3486 on Wed Sep 18, 2013 10:18 pm

I don't think its me, I think its more of the stuff I use. I get polycrylic, I think its minwax. It comes in a green can I think. I hate to paint but I can handle that stuff. I brush it on then sand. I have had good luck after about 3 or four coats. I usually do one coat and let it set until I get home the next day. Then I wetsand and add another coat. I repeat this until I like the outcome. But it has a smooth coat and has the shine I like.

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Re: Grunow model 1191

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