Hi Mark ~ I had the same thought about the rivet potentially loosening with wear, and I think you make a very sound point (no pun intended) about it being hinged to get it to clear the motor plate when lifting for service. I believe I have a good answer to your question about how to easily disengage the horn driving mechanism to allow the motor plate to swing up completely without interference. My A-200 has the rigid (non swinging) stop finger, and plenty of evidence (in the form of scraped paint on the motor board) to indicate that the motor board has been scraped against it many times. I discovered that it is really quite easy to prevent this interference, with no disassembly of hard to reach parts, by simply lifting the entire horn/arm assembly straight up out of the round socket (fastened to the floor of the horn chamber; the metal part that accepts the bottom end of the horn pivot shaft). You can rest the bottom of the ball-end at the bottom of the shaft on the rim of the socket, instead of down in the hole, and this will lift the trip lever, affording the clearance to swing the motor plate up without risking damage. I'm not aware of any A-series uprights that don't have the hinged motor plate. I have always assumed that the three-bolted bracket motor plate mounting came starting in early 1915, along with the B- series standardized machines. Andy Baron On Jun 23, 2007, at 10:01 PM, Mark Lynch wrote: > Andy, > > Please add the mahogany A250 in my collection, serial number 3215, > to the > list that uses the two piece hinged stop finger. > > I hesitate to describe this as a "user adjustable" or "semi > automatic" stop > until that has be established through research. The use a riveted > joint to > provide stop adjustment is not good engineering prctice because the > joint > would soon wear and slip. Also, notice the tab to hold the finger > in the > fully extended position as in the one piece design. > > I that suspect that the hinged finger has to do with motor > servicing. The > A-250 motor plate is not bolted to the case like on the later C-250 > but > hinged on the right in the same way as theAmberola 1 (B) mechanism. To > service the Amberola the motor it is tilted up on the left and > placed on > the metal prop at the left end. I think this was planned for the > A-250. > Being able to retract the stop finger from overhanging the motorplate > provided the ability to do this. What is not clear to me at this > point is > how to easily disengage the horn drive mechanism (rack) to allow > the motor > plate to swing up completely without removing it from the pivots. > Perhaps > we can investigate this. If it was not found impractical perhaps > the hinged > finger design was scrapped. > > Are there examples of A-250's without the hinged motor plate which > use the > later 3 bolt mounting design? That would also be a reason to > abandon the > hinged stop finger. > > I would be most happy if you post the results of your survey. > > Peter, thanks for posting the photos. > > Best Regards, > Mark > Silver Spring, MD > > >> [Original Message] >> From: Andrew Baron <andy at popyrus.com> >> To: Antique Phonograph List <phono-l at oldcrank.org> >> Date: 6/23/2007 11:05:00 PM >> Subject: Re: [Phono-L] the early a-250 >> >> Thanks, Peter for this very welcome report. I've just returned from >> a day out in my vintage car and will take some time to review these >> latest comments and reply, most likely tomorrow. >> >> Thanks also for posting the images and password so that others can >> conveniently view them. >> >> Fascinating stuff about the serial numbers. I can add more to this >> when I get a moment. >> >> Thanks to Peter, Ron, George, John, Rich and Bruce for the input. If >> any others of our readers have more to add to the serial numbers and >> details of the A-250 or other first-generation D.D. phonographs, I'd >> love to include the data in our compilation. >> >> Best to All, >> Andy Baron >> >> On Jun 23, 2007, at 5:24 PM, john robles wrote: >> >>> "The highest Model A 250 serial number I've ever seen was in the >>> mid-12,000 range of numbers". >>> Hmm, my own A250 is numbered 12080, so I guess it is later in >>> production than I thought. Either that or it is the one that Ron is >>> talking about since he's been to my house a few times. >>> There is another difference int he A-250 that I haven't found in >>> the others. The lock mechanism takes a key that has only one notch >>> cut into the 'tooth', not two as in all other DDs I have had or >>> seen. I have a Dolphin key that has the one notch cut in it as the >>> other will not fit. >>> John Robles >>> >>> Peter Fraser <pjfraser at alamedanet.net> wrote: >>> Hi - >>> >>> Well, I heard back from Ron Dethlefson, and enclose his response >>> below. >>> >>> And here are the pictures of Andy's machine, plus some additional >>> oxidozed bronze hardware pix from Bruce Mercer: >>> >>> http://homepage.mac.com/pjfraser/phono/PhotoAlbum233.html >>> >>> the password is "pook2e" (no quotes). >>> >>> For large-scale versions of the pix, use the slideshow button, or >>> single-click the individual shot in which you're interested. >>> >>> Cheers, >>> >>> Peter >>> pjfraser at alamedanet.net >>> >>> Begin forwarded message: >>> >>>> From: ronald dethlefson >>>> Date: June 23, 2007 9:53:26 AM PDT >>>> To: Peter Fraser >>> >>>> Subject: Re: pictures of the early a-250 >>>> >>>> Nephew, >>>> >>>> Yes, the stop mechanism shown is the first one. It's the same as >>>> on my A-250 #161. I've seen these mechanisms on #158 and #171. >>>> They probably were on the first 200 A250s manufactured in late >>>> 1912, according to Frow. A250s through #1200 were manufactured by >>>> March 1913, again according to Frow. The sound vents in the sides >>>> of the cabinets ended about #1200 too. I suspect that the stop >>>> mechanism was changed due to some patent issue. So much of the >>>> factory documentation was destroyed in the Dec. 1914 fire that the >>>> only way to document changes in Model A pnonographs is to look at >>>> the machines themselves. At least we now know that the first stop >>>> mechanism, was in use into the 1400 range of serial numbers. >>>> >>>> One other Model A tidbit. I've never seen a Model A 250 numbered >>>> lower than #109. This leads me to suspect that serial numbers >>>> began with 100. The highest Model A 250 serial number I've ever >>>> seen was in the mid-12,000 range of numbers. >>>> >>>> Regards, Uncle >>>> On Jun 22, 2007, at 11:58 PM, Peter Fraser wrote: >>>> >>>>> >>>>> >>>>> Early_A_250_levers >>>>> >>>>> >>>>> >>>>> >>>>> Later_A-250_controls >>>>> >>>>> >>>>> >>>>> >>>>> A_250_bedplate_detail >>>>> >>>>> >>>>> -- Peter >>>>> pjfraser at mac.com >>>> >>> >>> >>> _______________________________________________ >>> Phono-L mailing list >>> http://phono-l.oldcrank.org >>> >>> _______________________________________________ >>> Phono-L mailing list >>> http://phono-l.oldcrank.org >> >> _______________________________________________ >> Phono-L mailing list >> http://phono-l.oldcrank.org > > > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org