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Old 6th September 2010, 05:08 PM   #11
Mooly is offline Mooly  United Kingdom
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Oh yes, the PLL... that's something totally different and not related to the master clock .
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Old 6th September 2010, 05:50 PM   #12
liquias is offline liquias  Israel
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Mooly, thanks.
No solder blobs at any pin.
I've re soldered the crystal and made sure contacts are fine.
I checked earlier every pin with the scope. as I wrote there seems to be some active data lines between this IC and the D/A. nothing I can define as "out of the ordinary" - except of course - NO CLOCK .
I checked the ICs grounding resistance to the PCB ground -zero. looks OK.

Would you suspect the two 18pF caps driving the crystal ?
Where would you suggest I can look for SM5807 ?
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Old 6th September 2010, 08:35 PM   #13
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Do you get any voltage at D101, D102?
Any voltage at IC105 (pin16)?

Last edited by fastvideo; 6th September 2010 at 08:43 PM.
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Old 6th September 2010, 08:50 PM   #14
liquias is offline liquias  Israel
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Yes, I do.
IC105 pin 16 reads 5vdc, no ac ripple.
d101 , d102 read about +/- 7vdc (not extreamly stabilized, but fine for zenner regulation).


10x for helping.
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Old 6th September 2010, 09:14 PM   #15
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Any clock signal found on the microprocessor?

Last edited by fastvideo; 6th September 2010 at 09:17 PM.
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Old 6th September 2010, 09:43 PM   #16
liquias is offline liquias  Israel
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Well, no.
I have checked both the PS and the cpu very thoroughly today, and also had allot of help I have described everything I found in my previous posts.

No clock signal at the cpu.
Got a PLL signal but as it appears, no master clock.
Looking more into it later on...

thanks.
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Old 7th September 2010, 05:22 AM   #17
liquias is offline liquias  Israel
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OK,
Here are the latest checks and the results:
I have downloaded the data sheet for the digital filter IC and I understood that there are 4 outputs, in use, out if this IC (sm5807). pins 4,12,14,15.

I disconnected the 680 resistors leading out of pins 12,14,15 (R166,R165,R164 respectively) switched on, and nothing much happened.

BUT :
After disconnecting pin 4 (R162) when I switch on and wait for about 10 second, the display appears, very segmented, and slow (only some of the display at any given moment - Multiplexed ?), and if I press a button long enough, I get some action. For example the door open/close button reacts normally after holding it long enough. Plus, I get pickup activity. the pickup moves. (I think it is searching for a CD).

At first I didn't understand why everything seems to be slow, but then I hung the 'scope on the resistor's disconnected pin and I saw some (inductive?) 40-50KHz oscillations on it. about 300 times slower than the crystal's freq.

I changed the two caps (18pF) to new 15pF ones just to make sure it's not the caps. and even changed the crystal to another 16.9344Mhz crystal.
No improvement.

I then tried to "inject" a clock signal of my own. I decided to carefully connect my bench oscillator to the resistor's pin and "push" a clock into the circuit (relative to the PCB's ground).
Well this didn't work. I'm not sure why.
Maybe because my bench oscillator only gets to about 10MHz. I didn't have the guts to drive the signal above 4V PK-PK, so this could be another reason.


If anyone can think of anything more I can check aside from replacing the sm5807 I will be happy to do so.
I already ordered the IC from Ebay. It might take a while 'till it gets here.

I am wondering,
In case it is the IC, did it go because I did something bad ? Maybe the fast recovery diodes in the PS ? What could have caused this ?

Thanks guys,
Sephy.
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Old 7th September 2010, 06:09 AM   #18
Mooly is offline Mooly  United Kingdom
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I think you have done all you can, and it looks like the IC at the moment. The fact things happened when you disconnect pin 4 is promising too.
When you use a generator (depending on what it's like of course) 4 volts pk/pk output will be -/+4volt centered around ground... in other words your swinging the clock line above and below ground by 2 volts.
If the generator hasn't a DC offset you can set, what you need to do is AC couple the generator output with a 0.1uf or so together with a 1n4148 at the output end of the cap to clamp the signal to ground. Anode to ground.

Why/if ? the IC failed... dunno... if the PSU is OK then it's OK. High speed diodes wouldn't cause a problem. Worth checking no drys on the regs that could spike the rails.

Seems like the IC is used in Denon,

Dcd800 Sm5807Cp I/C Denon
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Old 23rd September 2010, 11:39 PM   #19
liquias is offline liquias  Israel
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Default Got the IC ...

Well, seems like you were right again, I'll say it with you, "ITS NEVER THE BIG IC!" .
I got the IC (sm5807 digital filter...), and replaced it. as you might have guessed by now, the player is playing again !
I still want to know how the old IC died. I really hope this won't happen again...

I am ecstatic.

thanks for everything !
Liquias.
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Old 23rd September 2010, 11:42 PM   #20
liquias is offline liquias  Israel
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Mooly,
How come I got the PLL but had no master clock ? isn't the PLL derived from the master clock ? what if for instance I wanted to upgrade the clock on such a machine, which clock needs to be upgraded, the PLL or the master clock?

Liquias.
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