Kyocera receiver not remembering stations

Well that's why, the battery is missing!

On 4/21/2010 12:40 PM Meat Plow spake thus:

D'oh! I knew it.

Alright, now, any *serious* answers?

Sorry couldn't help myself. A schematic would help find what keeps the volatile RAM powered up during off time or power failures.

A "super cap" may not last long in 1985 circuitry. They tended to use rechargable nicads back then like the 3.3v button cell battery pack I just replaced in a mid-80's Peavey guitar effects processor that loads into writable memory a patch list pulled from NVRAM when reset to factory patches.

Get some light and inspect it closely if you haven't. It may have a super cap depending on how long they designed it to be powered down.

On 4/21/2010 1:10 PM Meat Plow spake thus:

Someone else in another newsgroup (rec.audio.tech) also suggested a supercap. But it turns out to be a battery after all (actually a 3-volt Li-Mn cell labeled "LF-1/2 W"; anyone heard of that chemistry? I haven't).

I'm going to the local electronics store to see if they have a replacement cell.

Yeah a limn is just a lithium cell. .

Hi!

Well, I'd wonder if there is a battery compartment on the unit anywhere. Not trying to be disrespectful or anything, just saying that a lot of older equipment used conventional batteries (AA/AAA cells) to keep the memory running.

I have a Pioneer SX-5 stereo receiver that uses two AA batteries. Lifetime seems to be around a year or so.

William

Hi!

Dunno. I've got a Fisher tuner based on a Toshiba chipset (a 4-bit microcontroller with integrated memory and a separate display driver) that uses a supercap to keep the memory running.

It's been unplugged for weeks at a time between uses and somehow keeps the stations memorized. I'm guessing the Toshiba microcontroller is kept just barely alive, perhaps only a refresh current is applied to the internal memory?

William

Also look for a square/rectangular box like thing, about 3/4" x 1 inch usually black in color.

"David Nebenzahl"

See:

... Phil

On 4/21/2010 12:18 PM David Nebenzahl spake thus:

But of course, as readers of this thread know, further investigation did in fact reveal a battery (3-volt Li cell).

Clipped off the old cell (it was attached to the board with little spot-welded-on "legs"). Found a very similar cell in my battery collection (flat 3-volt Li large "hearing-aid" style cell). Soldered a couple wires to it, soldered it to old battery connections, wrapped it with electrical tape and tucked it into a slot behind the front panel. The receiver now remembers all presets.

By the way, wasn't there a thread here recently about the difficulties of soldering connections to such batteries/cells? I had no problem at all; I cleaned up spots using fine sandpaper (320-400 grit silicon carbide), then used my old non-lead-free solder and a clean tip on my iron. Connection was bright and solid.

I recently soldered a 2032 in a Nintendo Game Boy game cartridge for my son. He wasn't able to save games anymore and the cartridge was quite old. He did some research and came up with the idea to replace the 2032. It had legs spot welded and all I had was a blister pack of several 2032 watch batteries. I did scrape a little on each side then got the area to accept some solder and added some legs. It wasn't any issue soldering. The only thing is that it could damage the cell if you heat it too long. Scraping or sanding and some decent rosin core Kester does the job.

It's interesting how many expensive products (and I'm including devices that sell or sold for over $1000) use soldered-in backup cells, rather than a battery holder. The battery in a product that gets regular use will often last long behind its nominal life (10 or 15 years, versus 5), but that's still no excuse. Indeed, one of the advantages of using a socket is that you can replace the cell /while the unit is operating/.

My hall synthesizers use a lithium coin cell for backup, and I've replaced their soldered-in cells with sockets.

hillarious. I was just about to mention that stereo when AA batteries were mentioned.

do you know what the weird "AM stereo" RCA jack on the back is for?

Does is seem pretty common for those older supercaps to leak what looks like machine oil?

It's likely for a stereo AM adapter.