Steve
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vintageradio.co.nz
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Post by Steve on Dec 6, 2018 19:06:23 GMT 12
Well, every now and then I have a radio that is too good to part out, but too broken to keep... and this was one of those. It came to me with the dial in a plastic bag, but it was in otherwise good nick for its age.  How I got the dialSo I had some free time over the last couple of days and I set about laying out the parts on my scanner  I like to imagine this happened due to a stray tommy-gun round during a gangland raid in the 30'sMy next step was to import the scanned image into Inkscape, a vector graphics package capable of recreating artwork like this, and then slowly and painstakingly recreate each individual graduation, the band bars, the frequency numbers and all the rest. The hardest and most satisfying part was the Gulbransen logo, and the second hardest and least satisfying part was the Wells Gardener logo which gave me a lot of grief towards the end. You can see the transparent black parts which I have drawn over the image (which is only there as a template). The nearest font (almost perfect) I found for this dial was Ariel, although the 1 is too wide and the decimal point is too big - but its pretty close, and it works. I may look to see if I can find a closer open font, but for now I'm leaving it as-is. I have in the past completely recreated all ten numerals from scratch using the original dial where I couldn't find a suitable font  |
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Post by dada on Dec 6, 2018 19:21:51 GMT 12
Did you try James to see if the NZVRS had a spare dial or scan? D.
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Steve
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Post by Steve on Dec 6, 2018 19:23:19 GMT 12
Once complete, it was printed to make sure it looked right - which it did, then loaded into laser engraving software ready to to a test print... which did not go so well. No photos of that process, but it took around 3 test prints and a lot of re-working of a couple of things in the artwork to get it to scan properly in the laser equipment. Once I was happy with it I loaded the acrylic sheet in and crossed my fingers and toes. All good - it came out looking pretty good, although at this point I realised I hadn't reversed the artwork, which means the engraving is on the outside - something I had meant to do but I'll put it down to being tired... I will have to run another one off at some point, but the results are fairly acceptable. The engraving takes ink quite well, so I experimented with the logo and some gold-coloured ink, heres the results:   Before and after Its sitting a little low in the cabinet, but otherwise I'm fairly pleased with the results. One more radio saved (until I find all the faults in the chassis and it drives me nuts).  (The photos can be clicked to enlarge, then click back to come back to the forum) Laser engraving is a simpler process than screen printing, although the equipment is somewhat more expensive to get into. I went this way because I have access to the gear, and I have many years of using the software as well. Its probably not appropriate for dials like, for example the Columbus model 5 which has multiple layers of different colours, but dials like this are just right for it - the next one will be a test dial for a Columbus model 66 which should work well. Cheers Steve |
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Steve
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Post by Steve on Dec 6, 2018 19:24:58 GMT 12
Did you try James to see if the NZVRS had a spare dial or scan? D. I thought about it, then figured that if he did, someone else could have it - this way I got to play with awesome toys that can burn your retina from your skull in seconds!  |
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Steve
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Post by Steve on Dec 6, 2018 19:32:38 GMT 12
Here is an image of an original dial with the recreation below... the graduations are not 100% perfect, nor is the colour... the next version will probably be better  |
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Post by radioholic on Dec 14, 2018 16:49:30 GMT 12
This is amazing Steve - well done! James
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Steve
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Post by Steve on Dec 16, 2018 23:46:42 GMT 12
Thanks James |
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Post by elorens on Dec 15, 2019 17:32:12 GMT 12
This is amazing Steve - well done! James James, is there a library of dial images held by NZVRS? I have some scans I could provide if these were helpful. Some are from unknown radios, but may be of use to someone. If so, what is the mechanism for uploading? Cheers Lawrence-- |
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steveng
New Member
I have been asked to fix Gulbransen s/n 7D 732835. Is the 7D it's model?
Posts: 1
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Post by steveng on Dec 16, 2019 22:16:46 GMT 12
Hi Steve, I am a new member and a little out of my depth with a Guibransen that looks a lot like your one. I am at the end of a curer in electronics, in which I have had very little valve experience. I see you refer to yours as a 7L, the serial number on mine starts with 7D, so is that the model? Mine has the similar layout to yours, four knobs along the bottom. Above that a round glass window through you see the two hand station pointer and scale along with volume and tone level indicators. Above this is the speaker, much as yours is. The two coils on the speaker are good and the rectifier 80 valve on top of the transformer lights up as it should. The case has a lot of borer holes in it and it was drooped recently. I have glued the case where it had split, back together. My uncle gave it to me to fix but before I spend too much time or money on it I would like to know something of its history and pedigree. I could not find any pictures of it listed under Gulbransen.
StevenG
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Post by radioholic on Dec 19, 2019 21:32:36 GMT 12
Hi Steven The Gulbransen 7D was made by Wells-Gardner (USA). The schematic is in the Riders manuals. I am going to try to attach it to this reply. I have more info on the 7D but the file is bigger than 1MB so I can't attach it here. Email me (james.justjazz@gmail.com) and I will send it to you. James Attachments:
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Steve
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Post by Steve on Dec 24, 2019 16:29:57 GMT 12
Hi Steven, I've never had one of these fully apart, but I believe they have a reputation for rot in the IF coils (and probably other coils). The chassis is American as James said, so if you don't find anyone here with experience in this chassis the Antique Radio Forums might be a good place to try as well - there is a post on your chassis here that might be useful: www.antiqueradios.com/forums/viewtopic.php?f=6&t=343060Nostalgia Air has the Riders manuals in rough scans that can supplement the schematic James gave above. www.nostalgiaair.org/Resources/download.asp?FN=\M0023470.pdfIn terms of general things that valve radios need to get them going - power supply electrolytics (C16, 17) and the decoupling cap between the 6B7 and the 42 should be replaced before even attempting to power it on (not to mention a general check to ensure nobody has wired something stupidly in the mains section. All the caps will eventually need replaced if they haven't already because they degrade over time - use 630V poly's. I'd go with at least 500V working on the power supply electros as the voltage across these peak high on power up. Also, power it up with a dim bulb tester while working on it to make sure it can't pull a high current and break something irreplaceable - effectively you're just putting a 60W incandescent bulb in line with the phase to act as a current limiter. If it glows bright you've got a problem, shut it off. Hope that helps... feel free to start a new thread on it here and ask questions as you go through the restoration... there are some smart cookies here, and the odd person like me who's just too stubborn to give up despite not being a smart cookie at all. They do say time is a substitute for knowledge - so as long as you're not in a hurry you'll get there Cheers, Steve |
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