Help restoring National Panasonic R-330 Radio - UK Vintage Radio Repair and Restoration Discussion Forum

PedroFarinha · 1st Feb 2020, 7:59 pm

Hi everyone. I'm trying to restore my father's old radio but I'm a complete beginner in electronics. I'm hopping that someone can point me in the right direction.
It is a National Panasonic R-330. I've cleaned and tested it but it's not working. I can only hear a low volume static sound. Neither the tuning or volume dials do anything. Any idea of what can be wrong? Thanks, Pedro

paulsherwin · 1st Feb 2020, 8:19 pm

I keep saying this endlessly, but have you cleaned the wavechange switch contacts thoroughly with contact cleaner?

PedroFarinha · 2nd Feb 2020, 1:28 pm

Thanks for your response Paul. No, I haven't and they really rusty inside. Am I supposed to take it apart and clean it?

Thunderbird5 · 27th Apr 2020, 11:04 am

Pedro, I just saw your post because I was looking for history of Panasonic, i repaired a R-330y today with similar problem to yours. But mine is different to your picture.

I will try to describe anyway. it may help.
The radio had a small amount of noise, without change when tuning, all bands similar.
I checked the oscillator with an oscilloscope. That is working
I discovered with a strong signal it was operating poorly, no AGC action, needed 1mV
By touching a wire to the first RF transistor 2SA101, collector has red dot on side of metal case, there was lots of noise
On your board, this transistor might be in the middle of the cutout corner on main board, near speaker magnet. on my radio it was middle top of board, totally different layout.
I removed this transistor, measured it and found the base junction had blown out.
i suspect previous owner who was a ham, now SK, might have had an external antenna connected or high power transmitter nearby. it is unusual for these transistors to blow - unless they are fiddled with. I replaced it with the nearest germanium PNP transistor I could find - Mullard OC45
Immediately the radio was fully working - although it was misaligned - more bad fiddling by others - tip - if you adjust anything first step is to use marker pen to show where you started, which he had done, it helped a lot.
I tell you this whole story because the fault is very similar, you might be able to take this information to someone who knows radio, or get a diagram from radiomuseum
https://www.radiomuseum.org/r/panaso...er_r_330y.html
It would be nice to get yours working, they are good radios in their day. besides, nothing else to do in lockdown here and we need AM radio the electricity failed yesterday
Ralph

1st Feb 2020, 7:59 pm	#1
PedroFarinha Diode Join Date: Feb 2020 Location: Prior-Velho, Portugal Posts: 2	Help restoring National Panasonic R-330 Radio Hi everyone. I'm trying to restore my father's old radio but I'm a complete beginner in electronics. I'm hopping that someone can point me in the right direction. It is a National Panasonic R-330. I've cleaned and tested it but it's not working. I can only hear a low volume static sound. Neither the tuning or volume dials do anything. Any idea of what can be wrong? Thanks, Pedro Attached Thumbnails

1st Feb 2020, 8:19 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Help restoring National Panasonic R-330 Radio I keep saying this endlessly, but have you cleaned the wavechange switch contacts thoroughly with contact cleaner?

2nd Feb 2020, 1:28 pm	#3
PedroFarinha Diode Join Date: Feb 2020 Location: Prior-Velho, Portugal Posts: 2	Re: Help restoring National Panasonic R-330 Radio Thanks for your response Paul. No, I haven't and they really rusty inside. Am I supposed to take it apart and clean it?

27th Apr 2020, 11:04 am	#4
Thunderbird5 Diode Join Date: Apr 2020 Location: Auckland, New Zealand Posts: 1	Re: Help restoring National Panasonic R-330 Radio Pedro, I just saw your post because I was looking for history of Panasonic, i repaired a R-330y today with similar problem to yours. But mine is different to your picture. I will try to describe anyway. it may help. The radio had a small amount of noise, without change when tuning, all bands similar. I checked the oscillator with an oscilloscope. That is working I discovered with a strong signal it was operating poorly, no AGC action, needed 1mV By touching a wire to the first RF transistor 2SA101, collector has red dot on side of metal case, there was lots of noise On your board, this transistor might be in the middle of the cutout corner on main board, near speaker magnet. on my radio it was middle top of board, totally different layout. I removed this transistor, measured it and found the base junction had blown out. i suspect previous owner who was a ham, now SK, might have had an external antenna connected or high power transmitter nearby. it is unusual for these transistors to blow - unless they are fiddled with. I replaced it with the nearest germanium PNP transistor I could find - Mullard OC45 Immediately the radio was fully working - although it was misaligned - more bad fiddling by others - tip - if you adjust anything first step is to use marker pen to show where you started, which he had done, it helped a lot. I tell you this whole story because the fault is very similar, you might be able to take this information to someone who knows radio, or get a diagram from radiomuseum https://www.radiomuseum.org/r/panaso...er_r_330y.html It would be nice to get yours working, they are good radios in their day. besides, nothing else to do in lockdown here and we need AM radio the electricity failed yesterday Ralph