National Panasonic Radar Matic RF-1000 - UK Vintage Radio Repair and Restoration Discussion Forum

cashaw1972 · 24th Sep 2015, 2:59 pm

Hi,

I recently picked one of these up cheaply as non-working. It turned out to be a bad battery box and was quickly fixed.

I am intrigued as to how it's clockwork automatic tuning mechanism works. As mine seems to be working fine, I dare not try to dismantle it. I guess the clockwork mechanism get's a signal when the IF hots a station, but what sort of mechanism then triggers the clockwork to stop running ? I guess there must be some sort of brake which is triggered, but I am not exactly sure how it would work.

As the clockwork will not run when the radio is switched off, then I am guessing there must be some sort of solenoid which is activated when the radio is on which in turn releases a brake. Am I on the right track here ??

AlanC · 26th Sep 2015, 4:39 pm

Hi,

Not sure if the R-1000 and RF1000 are the same or similar; I found this thread on antiqueradios.com; which includes a link to a circuit diagram and layout.

It looks like a sample of IF is taken from just before the detector and fed through a series crystal filter which will give it a very narrow passband. The resulting IF signal is then amplified by a fairly conventional IF stage, before diode rectification and a 2-stage DC amplifier driving a relay. This would be necessary to ensure that tuning stopped when the signal was centred within the IF passband.

The relay contacts do various things; mute the audio by shorting the bias on the driver stage, alter the gain of the 1st IF stage, and open the path to ground of the emitter of the relay driver stage to cut off the relay current.

You'll also see that the layout diagram on the second page shows that the relay armature also actuates some kind of mechanical stop on the 'spring motor', though its not too clear. It doesn't take much power to stop clockwork- you only need to put something in the path of a pin attached to a wheel; every striking clock does this to halt the striking train at the end of the strike. I'm guessing this is what the relay does. It may then mechanically latch in that position until the seek button is pressed again.

Thanks for a very interesting digression!!

cashaw1972 · 27th Sep 2015, 9:06 pm

Thank you for pointing me in the right direction ! Very interesting reading.

It's a lovely little radio, solidly made and performs well for a 50 year old set.

Reelman · 28th Sep 2015, 9:50 am

How strange this thread should just appear, I just bought the RF-980L at the National Hamfest on Friday. This is also a Radar Matic model but is 4 wave bands and an electric motor drives the auto tuning. Fascinating to watch but quite a delicate mechanism I believe. Would certainly like to find the manual/circuit for this one. Pretty rare in the UK.
Cheers,
Peter

24th Sep 2015, 2:59 pm	#1
cashaw1972 Retired Dormant Member Join Date: Nov 2013 Location: Stockholm, Sweden Posts: 27	National Panasonic Radar Matic RF-1000 Hi, I recently picked one of these up cheaply as non-working. It turned out to be a bad battery box and was quickly fixed. I am intrigued as to how it's clockwork automatic tuning mechanism works. As mine seems to be working fine, I dare not try to dismantle it. I guess the clockwork mechanism get's a signal when the IF hots a station, but what sort of mechanism then triggers the clockwork to stop running ? I guess there must be some sort of brake which is triggered, but I am not exactly sure how it would work. As the clockwork will not run when the radio is switched off, then I am guessing there must be some sort of solenoid which is activated when the radio is on which in turn releases a brake. Am I on the right track here ??

26th Sep 2015, 4:39 pm	#2
AlanC Hexode Join Date: Jul 2006 Location: Sheffield, South Yorkshire, UK. Posts: 312	Re: National Panasonic Radar Matic RF-1000 Hi, Not sure if the R-1000 and RF1000 are the same or similar; I found this thread on antiqueradios.com; which includes a link to a circuit diagram and layout. It looks like a sample of IF is taken from just before the detector and fed through a series crystal filter which will give it a very narrow passband. The resulting IF signal is then amplified by a fairly conventional IF stage, before diode rectification and a 2-stage DC amplifier driving a relay. This would be necessary to ensure that tuning stopped when the signal was centred within the IF passband. The relay contacts do various things; mute the audio by shorting the bias on the driver stage, alter the gain of the 1st IF stage, and open the path to ground of the emitter of the relay driver stage to cut off the relay current. You'll also see that the layout diagram on the second page shows that the relay armature also actuates some kind of mechanical stop on the 'spring motor', though its not too clear. It doesn't take much power to stop clockwork- you only need to put something in the path of a pin attached to a wheel; every striking clock does this to halt the striking train at the end of the strike. I'm guessing this is what the relay does. It may then mechanically latch in that position until the seek button is pressed again. Thanks for a very interesting digression!! __________________ Always expect the unexpected...

27th Sep 2015, 9:06 pm	#3
cashaw1972 Retired Dormant Member Join Date: Nov 2013 Location: Stockholm, Sweden Posts: 27	Re: National Panasonic Radar Matic RF-1000 Thank you for pointing me in the right direction ! Very interesting reading. It's a lovely little radio, solidly made and performs well for a 50 year old set.

28th Sep 2015, 9:50 am	#4
Reelman Octode Join Date: Aug 2008 Location: Rotherham, South Yorkshire, UK. Posts: 1,724	Re: National Panasonic Radar Matic RF-1000 How strange this thread should just appear, I just bought the RF-980L at the National Hamfest on Friday. This is also a Radar Matic model but is 4 wave bands and an electric motor drives the auto tuning. Fascinating to watch but quite a delicate mechanism I believe. Would certainly like to find the manual/circuit for this one. Pretty rare in the UK. Cheers, Peter