Denon 2900 strange clock behaviour

[D.A.R.R.Y.L.]

Hi All,
I have modded my 2900 with a tent XO3 and XO supply.
Guido has modded the clock to give 3v3 for usage in conjunction with the sm8707 ic in the 2900.

Now for the strange part. The clock works for say a day or two. When switching on the 2900 on day three the display only lights up (matrix stripes) and does not react or display any text like 'LOADING' or otherwise.

I solder back in the old clock and voilá, it works again.
Anybody any ideas?

Thanks.

 

[Ulas]

If the XO3 doesn't work and the stock clock does, I recommend sticking with the stock clock.

 

[D.A.R.R.Y.L.]

Hmmzzz, not a useful answer.
I want to resolve the problem, not avoid the problem.
It works for others in the same system, why not in mine.

 

[Jocko Homo]

Have you stuck on 'scope probe on it to see how long it takes for it to come up?


Jocko

 

[Ulas]

DARRYL, What did you expect? You didn't post any information that gives a clue as to what the problem might be. The Tent XO stopped working on day three. That's all. Was the oscillator still oscillating? Was the power supply still powering? Did any connections come loose? What problem determination steps did you take? What are your skills and what measurement equipment do you have available? If you want help you have to give us more to work with.

 

[D.A.R.R.Y.L.]

Power supply is powering, because the led on the clock is lit.
The strange part is that the clock is up to. The 2900 doesn't seem to pick up the signal.

 

[georgehifi]

D.A.R.R.Y.L. I've done quite a few of the Tent clocks now, and I had a similar situation with a couple of them and fixed the problem by powering the XO supply and XO3 first, then switch the cd player on, in other words I had the XO supply and XO3 powered all the time.
It's like Guido's stuff takes a while to come up and if the rest of the cd player is on before the Tent stuff comes up, the player seems to lock itself out. so hook the mains side of the XO Supply directly to the input mains before the cd players mains switch so it is always powered. Worked for me on a couple of players.

Cheers George

 

[D.A.R.R.Y.L.]

Hi George,

My clock is on the whole time!
Guido has changed the output voltage to 3v3 for it to be in spec with the sm8707 ic in the 2900. So that should be ok.

He did it by placing a led in on the pcb. The strange thing is that the led sometimes burns brightly (then the clock works within the Denon) and sometimes it burns at lesser brightness and then the clock doesn't work.

I am a bit clueless @ the moment.

I so what that clock to work, because I experienced the benefits so clearly when it operated with the new clock

 

[Jocko Homo]

Without Guido to tell his trick with the LED.......it sounds like the voltage to the XO is out of range for it to mate up with your CDP.

You could measure the DC voltage to the XO, and tell us................

Jocko

 

[D.A.R.R.Y.L.]

Hi, voltage to the clock or the xo supply?
XO supply provides 22,8v without any load. When i attach the clock to the XO it drops to 16v. The dc measured on the clock output is 1,8v. Guido says this is correct for it to be 3v3, as it has a 50% duty cycle.
The clock voltage on the transistor (voltage regulator) is the required 5,5v.

Is it normal to use a led for lowering the voltage in a reliable manner?
Why not use a resistor?

regards,
Ramon