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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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28th Mar 2004, 5:21 pm | #1 |
Triode
Join Date: Jan 2004
Location: Flitwick, Bedfordshire, UK.
Posts: 47
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Reminiscing - Philips 555A
Hi all. I have been reminiscing about the days when I was a young lad (early 60s) being introduced to electronics for the very first time through watching my father repair radios and TVs. In particular, I have been casting my mind back to the stash of old radios consigned to the shed (regrettably all long gone).
One that I can vividly recall was a Philips radio in a Bakelite cabinet. From my memory of what the set looked like, and with the aid of the W.E.T. CDs, I have established that the set was a Philips 555A, circa 1938. I remember my father telling me at the time it contained unconventional valves and had an IF frequency that was different to that commonly in use. From the Trader sheet it is evident he was probably referring to its use of side contact valves and it having an IF of 128kc/s. I do not know for sure, but we are talking early 60s here and I guess it may have been because of availability problems with these valves that the set had been consigned to the heap in the shed I remember at the time being fascinated by the tuning mechanism on this set. I recall it had a mechanical push button tuning arrangement that operated by physically positioning the tuning gang. However, what really intrigued me was the gang capacitor itself. If my memory serves me correct, I think that instead of having vanes, the gang comprised of a set of meshing cylinders (looking very much like a set of very large beehive trimmers). It is at this point that somebody is probably going to tell me I have got it totally wrong, and that I must be confusing it with some other set. Not ever having come across this type of tuning capacitor before, and certainly not on any sets I have worked on since, this has got me wondering how common they were? Was it just Philips that used them and if so was it confined to just a few models? Was this particular Philips model possibly an import? I would be very interested to hear from anyone who can satisfy my curiosity on this point, and also if anyone knows of the existence of one these sets, as nowhere to date have I ever seen one listed in any collections, etc. Rod H |
28th Mar 2004, 5:38 pm | #2 |
Retired Dormant Member
Join Date: Mar 2003
Location: Bishop's Waltham, Hants, UK.
Posts: 939
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Re: Reminiscing - Philips 555A
Rod,
you're memory is correct! It is the Philips / Mullard " Direct action " tuning mechanism, and uses a sequence of mechanical stops for positioning the gang on pre-sets, and a " quick start " thread (the whole thread is only half a turn to move the gang in about 0.5 " ) operated by the dial cord for manual tuning. Operating a pre-set disconnects the thread, and you have to press a manual button to re-engage it. For the gang itself, don't think normal moving plate capacitor, instead think large scale Philips " Bee hive " or concentric trimmers, mechanically ganged together one behind the other. There has been an article on the device in the BVWS Bulletin, but I forget which issue. I have a Mullard version which I'm very slowly repairing for a friend - it sits on the end of the bench and gets worked on when I'm depersate, as it has had some of it's side contact valves replaced with octals, and needs almost complete re-wiring - bits get done as the parts become available. If you're interested, I'll dig it out and photograph the mechanism. Jim. |
28th Mar 2004, 11:13 pm | #3 |
Rest in Peace
Join Date: Apr 2003
Location: Edgware, North London.
Posts: 307
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Re: Reminiscing - Philips 555A
It was volume 22 No. 2 summer1997, and the article has a fine picture of a 555A.
Joe |
29th Mar 2004, 8:56 am | #4 |
Triode
Join Date: Jan 2004
Location: Flitwick, Bedfordshire, UK.
Posts: 47
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Re: Reminiscing - Philips 555A
Jim/Joe
Many thanks for your informative replies. That's now put my mind at rest and at least I now know I wasn't dreaming! Rod |