Just picked up a 1930s Battery operated Coronado

[vortalexfan]

UPDATE: My Oscillator Coil Came in the mail today and I got it installed and powered on the radio and it works!

I'll need to touch up the alignment a little bit as it is a little distorted sounding when its tuned into a station, but other than that its receiving a ton of stations and it gets really loud too!

See video link below to see a video I made of the radio in action.

https://youtu.be/8CO-H8qR_NU

[old_tv_nut]

Nice!

[Titan1a]

Bravo! Very, very nice.

[vortalexfan]

Originally Posted by Titan1a

Bravo! Very, very nice.

Thanks! This was my first repair where I actually had to replace more than just the caps or resistors in one of these radios, and it was my first farm radio that I've ever worked on.

And to be honest, with just my 2 1.2v NiMH rechargeable D batteries installed in a regular old Radio Shack Battery Clip wired up to a 1N4007 Diode for voltage drop the radio actually played for about 3 1/2 hours with plenty of juice to spare and the batteries weren't even fully charged!

[old_coot88]

Like a Boss! Coool, dude!

[vortalexfan]

Originally Posted by old_coot88

Like a Boss! Coool, dude!

Thanks! I think this will be my new Go To radio for Night Time DX'ing since it's a battery set and I could drag it out into a park out in the middle of nowhere and string up an antenna and just cruise the dial and see how many distant stations I can get in.

[fixmeplease]

Glad you have it fixed! Enjoy

[Kevin Kuehn]

Hey you did good. Seems to be working really well, and it's quite sensitive. That will be very interesting once you get outdoors away from all the modern rf noise sources. If you have a scope with a DC coupling you can monitor the AVC voltage line and watch the trace move up and down as you change the tuning.

[vortalexfan]

Originally Posted by Kevin Kuehn

Hey you did good. Seems to be working really well, and it's quite sensitive. That will be very interesting once you get outdoors away from all the modern rf noise sources. If you have a scope with a DC coupling you can monitor the AVC voltage line and watch the trace move up and down as you change the tuning.

Yes I do have an oscilloscope, and I think it does have DC Coupling but I'm not sure, the 'scope I have is a Tektronix Model 453 that is a Hybrid (part solid state part Nuvistor Tube powered).

How do I know if the 'scope I have has DC Coupling?

[old_tv_nut]

Originally Posted by vortalexfan

Yes I do have an oscilloscope, and I think it does have DC Coupling but I'm not sure, the 'scope I have is a Tektronix Model 453 that is a Hybrid (part solid state part Nuvistor Tube powered).

How do I know if the 'scope I have has DC Coupling?

You don't need a scope for this - a DC voltmeter will work.

[Kevin Kuehn]

Tis true but it's more fun watching the scope trace in a dimly lite room. Plus it's a great way to get comfortable working all those intimidating controls. Most modern scopes have a AC-DC coupling switch near each channel input.

[old_coot88]

Originally Posted by vortalexfan

...since it's a battery set and I could drag it out into a park out in the middle of nowhere and string up an antenna and just cruise the dial and see how many distant stations I can get in.

After a radio's been fixed and working good, often you can squeeze just a bit more gain out of the IFs; tune to a weak station that's almost "down in the grass" and then re-tweak each of the IF trimmers for absolute max gain. Often just the tiniest fraction of a turn makes a difference.

BTW, does the tuning spread match the dial markings pretty well?

[vortalexfan]

Originally Posted by Kevin Kuehn

Tis true but it's more fun watching the scope trace in a dimly lite room. Plus it's a great way to get comfortable working all those intimidating controls. Most modern scopes have a AC-DC coupling switch near each channel input.

Yes, I just looked at the front panel on mine and it does have a switch for selecting different coupling options including DC.

My Oscilloscope has 3 different probes 2 of them say 10x 100MHz 13pF 10MΩ 2 meter, and the 3rd one says 10x 10pF 10MΩ 2 meter, does anyone know what that's referring to?

See picture below.

[Kevin Kuehn]

Originally Posted by vortalexfan

My Oscilloscope has 3 different probes 2 of them say 10x 100MHz 13pF 10MΩ 2 meter, and the 3rd one says 10x 10pF 10MΩ 2 meter, does anyone know what that's referring to?

10x means it's a divide by 10 probe. So if you're measuring 10v it will look like 1v per division on the screen. Some scopes have both 1x and 10x positions marked on the volts per division selector. 10X also loads the measured signal less than 1X. The 13 and 10pf are the probes internal capacitance. Those aren't too critical until you're looking at square wave shapes. There's generally a capacitance matching trimmer for each channel input. You may have a calibration square wave terminal on the front panel you can connect the probe to and then you adjust the capacitance trimmer for that channel so the waveshape has square edges. 10M is the probes impedance.

[edit] Actually it's more likely the input capacitance trimmer is in the probe housing. You do have a 1kh calibration signal on the front panel left side.

[vortalexfan]

Originally Posted by Kevin Kuehn

10x means it's a divide by 10 probe. So if you're measuring 10v it will look like 1v per division on the screen. Some scopes have both 1x and 10x positions marked on the volts per division selector. 10X also loads the measured signal less than 1X. The 13 and 10pf are the probes internal capacitance. Those aren't too critical until you're looking at square wave shapes. There's generally a capacitance matching trimmer for each channel input. You may have a calibration square wave terminal on the front panel you can connect the probe to and then you adjust the capacitance trimmer for that channel so the waveshape has square edges. 10M is the probes impedance.

[edit] Actually it's more likely the input capacitance trimmer is in the probe housing. You do have a 1kh calibration signal on the front panel left side.

Can this 'scope be used to calibrate a signal generator, or a frequency counter?