Kyocera receiver not remembering stations
in [Repair]
|
From: David Nebenzahl on 21 Apr 2010 15:18 Question is about a Kyocera R-851 receiver, ca. 1985, 85 w./channel. Unit is in fine condition (many capacitators have been replaced) except for one thing: it doesn't remember radio stations. This receiver has 7 "presets" each for AM and FM. These can be set, and the unit will remember them so long as the power is on. Leave it overnight and the settings are gone. I'm ASSuming that these are stored in memory that may have battery backing. Opening the unit reveals no such battery/cell. Does anyone know enough about this unit to tell me what the likely culprit is here? Any links to schematics? Any help would be much appreciated. -- The fashion in killing has an insouciant, flirty style this spring, with the flaunting of well-defined muscle, wrapped in flags. - Comment from an article on Antiwar.com (http://antiwar.com)
From: David Nebenzahl on 21 Apr 2010 15:46 On 4/21/2010 12:40 PM Meat Plow spake thus: > On Wed, 21 Apr 2010 12:18:03 -0700, David Nebenzahl > <nobody(a)but.us.chickens>wrote: > >> Question is about a Kyocera R-851 receiver, ca. 1985, 85 >> w./channel. Unit is in fine condition (many capacitators have been >> replaced) except for one thing: it doesn't remember radio stations. >> >> >> This receiver has 7 "presets" each for AM and FM. These can be set, >> and the unit will remember them so long as the power is on. Leave >> it overnight and the settings are gone. >> >> I'm ASSuming that these are stored in memory that may have battery >> backing. Opening the unit reveals no such battery/cell. >> >> Does anyone know enough about this unit to tell me what the likely >> culprit is here? Any links to schematics? >> >> Any help would be much appreciated. > > Well that's why, the battery is missing! D'oh! I knew it. Alright, now, any *serious* answers? -- The fashion in killing has an insouciant, flirty style this spring, with the flaunting of well-defined muscle, wrapped in flags. - Comment from an article on Antiwar.com (http://antiwar.com)
From: David Nebenzahl on 21 Apr 2010 16:20 On 4/21/2010 1:10 PM Meat Plow spake thus: > On Wed, 21 Apr 2010 12:46:35 -0700, David Nebenzahl > <nobody(a)but.us.chickens>wrote: > >> On 4/21/2010 12:40 PM Meat Plow spake thus: >> >>> On Wed, 21 Apr 2010 12:18:03 -0700, David Nebenzahl >>> <nobody(a)but.us.chickens>wrote: >>> >>>> Question is about a Kyocera R-851 receiver, ca. 1985, 85 >>>> w./channel. Unit is in fine condition (many capacitators have been >>>> replaced) except for one thing: it doesn't remember radio stations. >>>> >>>> >>>> This receiver has 7 "presets" each for AM and FM. These can be set, >>>> and the unit will remember them so long as the power is on. Leave >>>> it overnight and the settings are gone. >>>> >>>> I'm ASSuming that these are stored in memory that may have battery >>>> backing. Opening the unit reveals no such battery/cell. >>>> >>>> Does anyone know enough about this unit to tell me what the likely >>>> culprit is here? Any links to schematics? >>>> >>>> Any help would be much appreciated. >>> >>> Well that's why, the battery is missing! >> >> 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. 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. -- The fashion in killing has an insouciant, flirty style this spring, with the flaunting of well-defined muscle, wrapped in flags. - Comment from an article on Antiwar.com (http://antiwar.com)
From: William R. Walsh on 21 Apr 2010 16:33 Hi! > Does anyone know enough about this unit to tell me what the likely > culprit is here? Any links to schematics? 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
From: William R. Walsh on 21 Apr 2010 16:35
Hi! > A "super cap" may not last long in 1985 circuitry. 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 |