It works!

majoco

Member
Joined
Dec 25, 2008
Messages
3,527
Location
New Zealand
Many months after the memory unit of my JRC NRD 515 finally succumbed to the rot caused by leaking dry cells eating the traces of the printed circuit board, I have finally ironed out the self-made faults of it's replacement. Now all I have to do is dial in on the thumbwheel switches the frequency I want, but a button-push goes back to the knob-twiddling. I had to have a guide to tell me the memory number for a specific station, now the guide just tells me the frequency! Easy!

The old board...

DSCF1453 sml.jpg

Memory unit in use.

DSCF1455 sml.jpg
 

commscanaus

Member
Joined
Jan 27, 2006
Messages
505
Location
Melbourne VK
Really like your NRD-515 Martin.
Very pleased you were able to repair the damage to the memory unit.
Just goes to show that any equipment fitted with batteries needs to be periodically checked to ensure that there is no deterioration and subsequent leakage.
Same goes for older equipment with electrolytic capacitors which can also leak and destroy circuit boards.

The circuit board in that JRC memory unit would just about be irreplaceable.

Commscanaus.
 

majoco

Member
Joined
Dec 25, 2008
Messages
3,527
Location
New Zealand
I didn't actually "repair" the damaged (ruined?) original memory board - it's been entirely replaced! Previously it had only 24 memory locations (but with a bit of fiddling I got that up to 48) but the memory IC's that were eaten by the battery acid are unobtainable. The outputs of the IC;s are now replaced by the thumbwheel switches which feed 6 4-way line drivers and then out to the receiver. It's a bit like a bowl of coloured spaghetti but it works! The 'preset-manual' pushbutton tells the receiver to listen to either the remote or it's internal tuning switch and knob.

DSCF1446 sml.jpg
 

ratboy

Member
Joined
Nov 3, 2004
Messages
837
Location
Toledo,Ohio
I learned the hard way to never leave batteries in equipment more than a year. I had the 96 Channel NRD-515 memory box and caught it just as one of the batteries started to leak. I had a calendar program that I set to remind me on the anniversary date, and later on did it with a cell phone's calendar app. Now, I change them all on my birthday, except for the stuff I use all the time.

I miss my 515, but selling it, the memory box, and speaker paid 2 months of my mortgage when I was short on cash. Now I'm about to sell all my HF stuff. Not because I need money, because I live in RF hell, where I can barely listen to anything below FM Broadcast.
 

majoco

Member
Joined
Dec 25, 2008
Messages
3,527
Location
New Zealand
After I cleaned up the board and got the memory unit going, almost 14 years ago now, I fitted a 4.7F (yes, Farad) 6v capacitor in their place which I charged from the 5volt rail - it would last for over 6 weeks before getting discharged. You can see it in the pic of the board at the top right corner- the white blob. I also use another capacitor to keep the kHz digits alive in the radio - that one does not last as long but not such a loss as the memory unit.
 
Top