Nakamichi with Alzheimer’s

[troystg]

My garage radio is a Nakamichi SR-2A and is consistently losing its memory now.

I "ASSUME" the storage supply cap for the tuner presets has expired.

Any one has a schematic or knowledge of which cap that would be so I can change it?

I plan on just overhauling it and changing most of the electrolytics, but I want to make SURE I get the correct one when I do that.

It has been a great shop radio but is now VERY annoying to have to retune the stations every time I go to work in the garage.

I find half the time now I just leave it off. And then I don't enjoy working out side at all.

I need to fix it because I have a ton of projects to complete and need my radio to while I build boxes...

Any help would be greatly appreciated.

[diyampss]

Hi Troy,
If you don't already have an ESR meter try this link with your signal gen and scope.
http://octopus.freeyellow.com/esr.html

I'm guessing the cap is a miniature size, low voltage and probably under 50mfd.

Good luck and have a great Thanksgiving!

Joe

[MikeB]

Often there is used a "goldcap", having 0.1-2Farad, low voltage type, very high resistance, but powerful enough to supply some cmos...
You can buy these as replacements. But Joe might be right and there is a simple elyt used for that, in this case i would look for a very low voltage type with high capacity.

Mike

[Frank Berry]

The cap will probably be rated at something like 5 farads/5 volts. It will be a "super cap".

It will be an upright tubular standing about half an inch tall.

[troystg]

Rgr that Both of you.

I was looking for a schematic or old tech who knew off hand.

If I have to start hunting for it I might as well change them all since they are the same age and most likely failing also.

[djk]

The cap is 0.47F 5V ESD type, and looks like a watch battery.

It may not be the problem.

Usually after replacing this cap and still having the problem, I find a 0.01µF power supply bypass cap that has gone leaky.

[anatech]

Right you are djk,
It's a little bigger than a watch battery, thicker. I thought there was also a possible leaky PCB issue due to close traces, I could be wrong. Man, I wish I had my manuals and bulletins! And yes, the cap can go leaky.

That's a nice set to have in the garage! Many people would love to have it inside the house. My TA-2 lives in the bedroom.

-Chris

[troystg]

Originally posted by djk
The cap is 0.47F 5V ESD type, and looks like a watch battery.

It may not be the problem.

Usually after replacing this cap and still having the problem, I find a 0.01µF power supply bypass cap that has gone leaky.

Rgr that, and I will open it up and look tomorrow.

Thanks for the second tip too. Now I will look for that also.

Will be spending lots of time working in the garage this winter since it's cooler and will realy appreciate having my jazz annoy he neighbors again... I am joking.. They only hear it when they come ask what I'm making this time.