Yet another Tivoli Model One troubleshoot...

mp52

Member
2020-01-27 6:25 am
Hi,

I've reviewed other posts on the forum for the Tivoli Model One but these are nearly all focused on the issue of hiss/scratchiness and tuning slippage in the device and diagnose cleaning/replacement of the varicon in the unit.

I'm getting a different issue so, before I rip it open, I'm keen to get some advice on possible causes. The radio now emits white noise on all input settings (AM/FM/AUX) at low/med volume. When the volume knob is turned up very loud the noise dissipates and the audio signal comes through. Switching internal/external antenna has no effect. Listening through the headphone jack doesn't produce as much noise at low volume but still requires volume to be at top level to let the audio come through.

Given the variability, is this pointing to shorting in the volume potentiometer at minimum settings or are there other things I should look at (e.g. cracks in PCB/bad solder joints). It basically started happening "overnight" and the unit wasn't dropped or damaged in any way.

Any help appreciated.
 

kb4mdz

Member
2018-07-06 1:06 pm
I'll help you revive this thread. I picked up a Model One, and it has an interesting set of symptoms.

1st, it came less the wall wart or standard 2-prong power cable. OK, found a wallwart in my junque drawer, good, powers on.

I can see the Power LED on, and the Signal LED comes on as I tune across the dial, both AM & FM. Here's where it gets fun: No audio from speaker. But if I take an aux. sound source and put it into the jack, I get sound out of the speaker. GOOD!!

If I put an earphone in the earphone jack, I hear nice audio. Great!! But since then I haven't had much time on the bench, so that's where it's at. So obviously it's something in the audio chain between the headphone out and the AUX In. But I've had no luck finding a schematic. ANYWHERE!!! Looks like i just need to work out the diagram on paper myself.

Again, that's about as far as I've gotten, what with other life things in the way. It will yield, but it may take some time.