Re: {Collins} 51S-1 PTO Issues



Hi Charlie, 


That resistor is really a 100 ohm resistor - newer body style (tan in color)  brn - blk - brn and measures 102 ohms. Hack job installation also.....


The PTO is a single tube round emblem with an MCN of what appears to be 273 (kind of faded). Appears to be the original one to the unit as all of the wires, except the one for the 1k connection, still had their red marking on the solder joint.


Tom
W3TA



-----Original Message-----
From: Charlie T via Collins <collins@xxxxxxxxxxxxx>
To: collins <collins@xxxxxxxxxxxxx>
Sent: Sun, Oct 1, 2017 11:33 pm
Subject: Re: {Collins} 51S-1 PTO Issues

Just curious if you actually measured R-62 as 100 Ω, or, is it possible thata 1kΩ resistor got hot enough to discolor the red band, making it LOOKbrown?Also, in a curious vein, does your early S/N radio have a round emblem PTO?More than likely it does, as most of the early two tube PTO's which wouldmay have been an original on a three digit S/N radio.And yes, that PTO output transformer is not critical.  Just get a smalltoroid and wind one yourself.I'll see if I can dig up the specs because I have had to do that at leastonce.If I remember correctly, it was around a 5:1 Z ratio, but that was a longtime ago.Agreed, it is a very unlikely part to fail. 73, Charlie k3ICH-----Original Message-----From: Collins [mailto:collins-bounces+pincon=erols.com@xxxxxxxxxxxxx] OnBehalf Of thoyer via CollinsSent: Sunday, October 01, 2017 9:42 PMTo: collins@listserve.comSubject: {Collins} 51S-1 PTO IssuesWorking on bringing SN 131 back to life. Found PTO not PTO-ing......... External to the PTO someone at one time replaced R62 with a 100 ohmresistor, schematic calls for 1k. So far this is the only area of rework Ihave found. Resistance measurements on V15 pins 5 and 6 were not making sense. PulledPTO out and found R504 was fried and R503 measured 77k - should be closer to56k. Measuring between pins 1 and 4 of T503 shows 33m - basically open. Caps C507and C508 are not shorted. Bottom line, I can replace all of the parts to bring things back in specBUT, what about T501? Anyone know of a source for these? Thanks,  TomW3TA*** You are subscribed to Collins as pincon@xxxxxxxxx. If you wish tounsubscribe, or modify your preferences please visithttps://mailman.listserve.com/listmanager/listinfo/collins ****** You are subscribed to Collins as thoyer1@xxxxxxxxxxx. If you wish to unsubscribe, or modify your preferences please visit https://mailman.listserve.com/listmanager/listinfo/collins ***



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