Kirk's Sparton 65 - Printable Version
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Kirk's Sparton 65 - morzh - 08-29-2017
...or at least Kirkk claims it is the 65.
He downloaded the sch from the Museum.
Seem to be in some degree of agreement with the chassis.
It has the curtain burner cord, that is.....good! And pliable! But, someone some time connected it wrong moving the nichrome wire in the plug to the opposite prong so in essence the same voltage is being supplied to the both ends of the filament chain. Then it was disconnected from the pin of the 25Z5 it went to (and left hanging within 1mm from it) and a diode was put to cut voltage in half to supply the filaments. I think it will supply a bit more than required and I cannot easily measure it with a DMM; theoretically at 110VAC it should give me 77V RMS which is pretty much what I need (75V), butt the meter shows about 45V DC and 42V AC which will give me about 60V or so when calculated.
I could try to fit a capacitor of 8.5uF (that should provide 312 Ohm of impedance instead of 126 Ohm active resistance, as there is the phase shift of 90 degrees; I have 8.2uF, worked for me in the past on one of these) and this will do it exactly for 120V AC, but the cap is large and will require space.
I decided against using the cord's own resistor: first, it will require major relocation of the wires and second, Kirk is terrified of the curtain burner cords, even though I think the probability of it putting his curtains on fire (heck, just don't use any curtains!) is just a few percent :
and is much less altogether than the one coming from the rest of his radios and his activities combined which to me is 50/50 : but I will accommodate his wishes, him being a scaredy cat he is.I tried it with the diodes yesterday; it comes up and buzzes very loudly; on one band (I think it is the BC) it kinda receives the local station but it is weak, garbled and overcome with the buzzing.
I looked into the box with the electrolytic caps; they are not exactly according to the sch; in the sch there are three electrolytics connected to carious points, and in the box two of them are paralleled and there is another one. I wonder if this is the reason for the buzzing. I also think Kirk only buys the radios with some evil spirits lingering in them and they need to be exorcised first, and I do not possess the power to do that. And Kirk has the opposite power of attracting them. Not sure what to do about that.
So, tonight's order of business: try to straighten out the electrolytic capacitors, as the gremlins usually live there for the most part.
RE: Kirk's Sparton 65 - OldRestorer - 08-29-2017
So sorry that I don't want my house burned down...
It is definitely a 65 so I don't know what is happening under the chassis.
RE: Kirk's Sparton 65 - Eliot Ness - 08-29-2017
Pretty unusual to find a resistance line cord (curtain burner) still nice and pliable. Be sure to save the cord for someone to use on a radio they'd only play for demonstrations. I think my Radio Keg radio uses a curtain burner, but I'm not sure of the resistance off hand.
RE: Kirk's Sparton 65 - Radioroslyn - 08-29-2017
Hey Mike,
You need to empty your PM box.
RE: Kirk's Sparton 65 - morzh - 08-29-2017
Just did.
RE: Kirk's Sparton 65 - morzh - 08-29-2017
(08-29-2017, 10:43 AM)Eliot Ness Wrote: Pretty unusual to find a resistance line cord (curtain burner) still nice and pliable. Be sure to save the cord for someone to use on a radio they'd only play for demonstrations. I think my Radio Keg radio uses a curtain burner, but I'm not sure of the resistance off hand.
Very typical is 120 Ohm
RE: Kirk's Sparton 65 - morzh - 08-29-2017
Well. Let's just say that the person who recapped the radio had very approximate idea as to the how to connect electrolytics and other things.
First, as I wrote before, the lytics were not according to the schematic. More to this, the wire colors were preserved, so why not do it right, right?
I reconnected the caps, plus I used some higher voltage caps with better ripple rating, as I think 160V is a bit low....though it is a half-wave, but they looked flimsy and so I reserved them for other uses....for someone who inherits them after I die: some noname small jobs they were.
Anyways, after the power-up the hum went away and the radio is receiving across the dial. My local station's music is garbled but the speech in other stations is ok. Maybe the AVC is not working properly, maybe....who knows.
As the radio was playing, I gave it a sniff, as I usually do, and felt some light smell coming from the bottom; I turned it over and the 50 ohm resistor across the 25Z5 plates was very warm, almost hot, which it shouldn't be. Then I realised the guy soldered the diode that supplies the filaments after the resistor, so it conducts extra....0.3A, which is way more than it should, resulting in extra....4.5W dissipation. I moved the diode where it should be, right to the AC input before the resistor, and the heating stopped.
Tomorrow I will try to find out why the local station is garbled and maybe align the ugly creature.
RE: Kirk's Sparton 65 - OldRestorer - 08-29-2017
Woah,
I am glad I bought it "partially restored"
RE: Kirk's Sparton 65 - morzh - 08-29-2017
Yeah.....the problem is, some folks, unfortunately, think they know stuff, when in fact they know something else. That doesn't stop them
And they can always call it "partially restored"
RE: Kirk's Sparton 65 - Kenneth F. Besso Jr. - 08-30-2017
that's wye,,,,I,,,,,AM NOT THE smartest in the VILLAGE----lololol
RE: Kirk's Sparton 65 - OldRestorer - 08-30-2017
(08-30-2017, 07:16 PM)Kenneth F. Besso Jr. Wrote: that's wye,,,,I,,,,,AM NOT THE smartest in the VILLAGE----lololol
RE: Kirk's Sparton 65 - Arran - 08-30-2017
It doesn't surprise me, Sparton seemed to use better quality materials then many of their competitors, rubber power cords excluded. To date I haven't run across a pre war AC/DC set made by Sparton, but given that there was a ban against AC/DCs in the Canadian Electrical Code until 1939-40 or so the only way I would run across one like Kirk's is if a U.S built Sparton crossed my path.
Regards
Arran
RE: Kirk's Sparton 65 - morzh - 08-30-2017
Well...attempted the alignment.
Out of three trimmers (the instructions actuallysuck a bit) one pair works and the C1 and C2 pair do not affect IF gain at all.
The 1500kHz seems to be right there.
The radio receives across the dial but not very loud, and distorted when the signal is strong.
RE: Kirk's Sparton 65 - OldRestorer - 08-31-2017
You can do it Mike... and by "can" I mean "have to"
RE: Kirk's Sparton 65 - morzh - 08-31-2017
The only things I have to do is eat, breathe, sleep and some other biological necessities that we don't have to discuss; the rest is by choosing.
At this point I chose to interest myself in that radio, but if it chooses to show undue intransigence, I might choose to devote my energy to something else, like an extra beer.