Philips GM2877 wobbulator - reporpoise, sell, or scrap for parts? - Page 1
Forum section: electronics / rf-microwave

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 08, 2016, 06:35:07 pm
content: Hi!I have this old philips 75ohm "wobbelsender" aka. sweep generator from the 50's, I think, specifically used for aligning VHF/UHF tv receivers.It's pretty shaky on the output side, but it does produce a swept output when you tickle it right (the manual speaks German, I do not), but it's very neatly constructed, with every section in its own silver plated box, interconnected by coax.I haven't really got any need for the instrument, but from the schematic, it seems you could just yank out one of the oscillators, and feed it to an output, for a fairly high-end VFO or signal gen. Rather, yank everything else out, so I can keep the tube supply and box.Would it be worth doing this, or should I just grab the air variable capacitors, vernier drives, and shielding boxes? Maybe sell it off?Which of the oscillators would be best suited for salvage/independent use? What would you do?Here's a schematic, for the modularity I was talking about, and because I myself prefer posts with pictures.thanks in advance.

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 08, 2016, 07:32:21 pm
content: If you talk pictures, do picturesAnyway, I wouldn't stop when I found one at the side of the road. It's beautiful made, but really really obsolete. If you have a use for an unstable VHF/UHF oscillator/wobbulator by all means keep it and use it, but it's too unstable frequency wise and output wise for today. So if you are not going to use it part it out and keep anything that you will be using in let's say the next year.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 08, 2016, 07:44:56 pm
content: Thatwaswhat I feared too. It might just be mine that's gritty and might have failed parts, but just touching or tapping the case slightly makes a rather large dent in the freq.might not even be worth using the cans as finished assemblies.-Strangely enough, mine's different from your picture. It lacks the toggle switch, has a banana socket more, and two xtal sockets... hmm.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 08, 2016, 08:43:22 pm
content: Well here's a pic of the construction before it goes. all silver-plated little boxes, interconnected with IEC antenna style connectors and coax.I just tested the individual oscillators, and they don't yield good output on their own either - in any case, I don't really do much UHF stuff, so I guess something better will get to live in those cans.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: October 08, 2016, 10:29:27 pm
content: Okay, this wasn't meant as a teardown thread, but look at that nice tuning fork like device in one of the oscillator cans:

author: antiekeradio
author_rank: Newbie
timestamp: December 15, 2016, 09:26:42 pm
content: As a tube gear collector I would definitely not recommend tearing it apart just to have some random parts in a bin. I have a similar one, bit older maybe. The quality of construction is really good but if a device is so old, dirty and rusty you can't expect it to be working anywhere near it's original spec, right? I bet you could restore it electrically (replace all paper + electrolytic caps, check resistor values, etc) and have a very usable instrument on the (admittedly limited) frequency range covered by it.If you are not planning on using it, better sell or give it away. You can only destroy a technology heirloom once.