Monday, 8 July 2013

If you cant stand the heat, dont be a test set!

After a lot of work and measurements, my Marconi 2955B decided to actually work again today. This is after several peoples advice, lots of measurements, and a good deal of relearning how to properly use an oscilloscope on my part! I also discovered that the unmarked x1/x10 switch on the scope probe I was using is actually the other way, and all my supposed bad measurements had been done on x10.

It seems the problem was ambient temperature, the last few days incredible heat made the workshop almost unbearable to me, and it seems completely unbearable to at least one of the 2955Bs circuits. Today, being considerably cooler, its working perfectly.

Sam came with me yesterday to the Red Rose QRP rally. I'd won Amtools charity auction for the entrance and lunch, but even with Sams round of toast, I think the charity gets the best deal! Still, I had some decent pie and peas and a brew which took most of the time we were there to cool! Picked up a set of telescopic fish poles to use as spreaders for the show cobwebb, IF i manage to get it built in time. I havent finished the Larkspur mast yet, nor tested the 40m antenna. At this rate we'll be falling back on the big fishpole and the link dipole.

Of the list of items I actually wanted, I think I got two. One, the isolation audio transformer, was found on a defunct 56k modem card for 20p. The other, a BF199 transistor, is somewhere in the dozens of transistors and hundreds of resistors I picked up in a £8 deal for the entire contents of a junk box! A bit steep for the transistor, but the box contained two brand new unopened Velleman component packs of electrolytics and ceramic caps, several unopened Tandy ICs of which two at least look to be quite rare, and a nice NOS ATP-4 valve. Thats just what ive dug out so far. The bits that are no use to me I should be able to sell to make a few bob to cover the cost of the box, and perhaps if im lucky make enough to go someway to offset the cost of the cobwebb spreaders.

Two things I do have to sell, are these Pye telecom extender boards -
Ive got no idea what they extend, they look like maybe Pye Olympic or Europa PMR radios. I'll offer them first on the Vintage forum for a couple of quid, someone might have a use for them. Theres a load of unused old Hunts capacitors in the box as well, not sure if anyone will want those!

So, I'll have a sort of the bag see what there is further to keep, and what else there may be to offer for sale. Ive still to shift those Marconi fill-guns, looks like the last person isnt interested anymore. Plus a Philips repeater and some met grade thermometers! The more I can sell the less Julie will complain at all my junk, and the less the show will cost me in antenna systems!

Well, ive the HF antenna mount on the car to test now. Im sure the bands are not as dead as that radio makes out, but the radio tests out fine. Dinner first I think though - frankfurters, onions, shrooms and scrambled egg, oh and a bit of red sauce.

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