Kenwood TK-630H question - backup memory/RAM?

[kf6iiu]

I have a pile of TK-630H lo band radios (a former American Red Cross standard radio - we have switched to Vertex VX-6000s now.) I was testing one and I disconnected power while the radio was on and it came back on acting like its memory was lost. A few days later, I power it up and it came up just fine.

The service manual contains the following unclear comment: "When the radio is connected to a car battery, the microcomputer is always backed up. If you disconnect the battery from the radio, the RAM contents disappear in a short time." There is a mod in the service manual to install a supercap to extend the backup period to 24 hr.

What the heck does that mean? These radios have not been powered up for years but all have retained their programming, except for the odd incident I described above. Should I be careful about disconnecting or connecting the radio from power when it is turned on?

Bonus question: Is there a low power programming option for these radios? They seem to draw about 18A and show about 80W on my wildly uncalibrated HF wattmeter. Nevertheless, I would expect them to draw more current if they were actually putting out their rated 100W.

 

[a417]

I have a pile of TK-630H lo band radios (a former American Red Cross standard radio - we have switched to Vertex VX-6000s now.) I was testing one and I disconnected power while the radio was on and it came back on acting like its memory was lost. A few days later, I power it up and it came up just fine.

The service manual contains the following unclear comment: "When the radio is connected to a car battery, the microcomputer is always backed up. If you disconnect the battery from the radio, the RAM contents disappear in a short time." There is a mod in the service manual to install a supercap to extend the backup period to 24 hr.

What the heck does that mean? These radios have not been powered up for years but all have retained their programming, except for the odd incident I described above. Should I be careful about disconnecting or connecting the radio from power when it is turned on?

Bonus question: Is there a low power programming option for these radios? They seem to draw about 18A and show about 80W on my wildly uncalibrated HF wattmeter. Nevertheless, I would expect them to draw more current if they were actually putting out their rated 100W.

The codeplug data is stored in EEPROMs onboard which do not require keepalive circuits. The option scrambler function settings are stored in the microcomputer. IIRC, (and tbh I probably don't at this stage) that the other operator selectable info was also stored in the microcomputer, like current OST settings, user scanlists, etc. That might be another radio line...it's been too long.

 

[AM909]

... Bonus question: Is there a low power programming option for these radios? They seem to draw about 18A and show about 80W on my wildly uncalibrated HF wattmeter. Nevertheless, I would expect them to draw more current if they were actually putting out their rated 100W.

They can probably be adjusted over a pretty wide range. Rated power is 110W @ 25A, so you're just about right. Dropping a dB or so in output won't matter much at all to performance and will make some finals, antennas, and cables refrain from melting prematurely.