[mcspack]

Hello all,

I'm finally fitting my hagclock into my machine Samsung hd 841 as instructed in this thread for superclock 3:

http://www.audiocircle.com/index.php?topic=12613&postdays=0&postorder=asc&start=230


the user had the same issues I did before he got it to work as noted in this thread:

http://www.referenceaudiomods.com/phpBB2/viewtopic.php?p=341&sid=3b9f2a861504cfc46b8b0516db5c5ada

Tthe unit powers up but doesn't load a cd, nor will it allow the tray to open, the user above was having trouble conneting his superclock and it wasn't getting the clock signal to his chip, He  eventually resolved this and I have conneted my clock to my machine in the way he suggests. I don't think that my clock is oscillating corretly though and that is why the chip isn't getting a signal, when I check the -+5v all is well, when I check the voltage across r13 i get ~ 170mV, too high I think?  the voltage at the lock test pont is ~1.5v.

 I am using the original can style clock that is out of this player for my crystall instead of the cylinder style, it is a uni player so it uses the 27khz and I believe it is a 3v instead of a 5v so that is how I have it configured, I left out c17 also as instructed. I did not solder the can crystal to the ground pad. Also I am drawing the positive and negative voltages from some diodes one has ~ +11v the other ~ -8.5v not sure if these are the best places to draw from??  I hope all this info helps.

thanks,

MC

[hagtech]

I've found the HAGCLOCK to be marginal at 27MHz, that's why I only sell it in the 11.2896 and 16.9344 versions it was optimized for.  That said, most attempts at 27M have worked.  So far, I've encountered two xtals that didn't fire up at that rate.

Voltage across R13 is a dc measurement.  It looks at the bias current of the JFETs.  When oscillating, it drops to about half.  At least the +/-5V supplies are working well, the input requirements very flexible.

Did you buy a different xtal to try?

jh

[mcspack]

thanks

I havn't bought a cylinder crystall yet I thought I'd try the one I removed from the uni player board first. I can certainly buy one if you think that it would be better. When you say it is marginal at 27mhz do you mean it doesn't reduce jitter as well, or just that it might not work? Anyway do you thnk my issue is that it is just not oscillating and that is why the voltage is higher across r13? I did try and measure the clock point voltage again using different sources for ground and the ground from the clock board shows the voltage as 2.1v so I guess that looks ok now too. Try a differet 27mhz crystal and I should be ok??

thanks again for your quick response.

MC

[hagtech]

Would be great if you could try a different 27M xtal.  Yes, problem is that oscillator doesn't start up, circuit is otherwise fast enough.

jh

[mcspack]

ok,

Here is what I'm looking at now ugh!

just to get me feeling good about my clock I decidd to take a 11m xtal and install it into my circuit and power it and test it via 12v battery. here are my findings.

with vcc and vee connected to the batery the led lights but when I connect the grd the light goes off, without ground I get  ~90mV  r13 reading and with it connected I get ~ 140mv, the cock test point is about 1.5v I didn't test it w/o grd connected.  I'm beginning to wonder if I might have a bad resistor or capacitor in my circuit as the testing isn't going well. maybe I don't need another 27m xtal?  I will try and check all the values in my circuit to make sure everything is ok . All of the solderjoints look good, I did include c17 cap for this testing. Let me know what you think.


MC

[hagtech]

You need two batteries to test.  HagClock requires both positive and negative supplies.

jh

[mcspack]

thanks jim,

I thought there must be something like that.

I'll try and let you know.

MC

[mcspack]

diode d3 was in backwards DOH! very small part!

MC

[mcspack]

Hey Jim,

that seemd to have done it as far as testing with the 11 mhz xtal! I feel good about my circuit build, So I tried it with the can xtal from my players board and it is in the ~ 80 mV range across r13. The player doesn't play yet and is still having the same symptoms as before. So it needs to be in the 50s or 60s mVs to oscillate?? I know that I have the clock hooked up properly and all the voltages going to the clock and at the clock check out. So I will order a cylinder style xtal and try that.  I am using 3vs instead of 5vs as my output voltage, is that correct as far as you know?  Maybe that is my issue if the ~80 mV reading means its oscillating. Thanks for all your help on this.

MC

[hagtech]

I only checked on board for that 50mV drop issue.  Easy to stop an oscillation to see the differences in bias.  I would not say that this is a foolproof test.  Just that I needed to come up with something for those folks without a fast oscilloscope.

Really, the best way to debug these things is to use the scope.

One other possibility is that the 100ms startup time might be too long.  Perhaps the CPU in that player is coming out of reset ahead of a stable clock.  You could try powering up the clock first (battery test), then the player.  If that is the case, all you need to do is change the value of C4 and C8 to something lower, like 1uF or 0.1uF.

jh  

[mcspack]

cool,

  I'll give that a try, currently the clock is powering up with the player so having it powered up ahead of the player is a way to see if it will work? I can do this easily. I'll let you know how it goes.

MC

[mcspack]

ok I think it is my crytal as starting it up prior to the CDP didn't change anything, ordering new xtal.

MC

[mcspack]

hmmm, new xtal same old problem  not sure what to check now, will I have to buy an osciloscope to do this? The xtal that I bought was a similar 18pF cylinder style from digikey, the part number XC965-ND the output across r13 is ~70mV and the output from the clock test pointis ~2V. all other voltages are fine, I tried setting it up with power before the player and afteer and with using different value caps for c4 and c8. I'm not sure what else to try, I also moved the clock right up to the rin 100 ohm resistor and conneccted the clock with the shortest possible connection, I read in some forum that  shortening the lead wires might fix this, I just don't believe that my clock circuit is getting a stable signal from the clock. I am sure I have the clock connected correctly, I'll recheck my clock circuit tomorrow and see if I have any bad solder joints., Is there anything else I need to do or try for this 27 mhx 3 volt clock?

thanks in advance

MC

[hagtech]

Really hard to debug without a scope.  You can always send it in to me, I can check.  

jh

[mcspack]

Success!

I decided that I needed to look once more at the way I was connecting this circuit to my player, I re read the posts of the superclock install in the second link I provided in my original post, It ade me confused which was good. I was then able to pursue some trial and error to see If I could figure out how to install this clock. It turned out that the third post in the referenceaudiomods link was more correct the aroach to take than the one in the first link. I removed all of the resistors in the circuit, ZR24 , ZR78 and connected theclock to the other xtal pad thruhole. This gave me access to the 74HC04 chip without the added resistance. This allowed the circuit to fire up. it turnsout that this connection doesn't talk to pin 142 like the superclock product might. instead it talks to the above mentioned chip and the Zoran chip at pins 143 and 144. I did have to jumper the smd tabs for ZR78 with a small piece of wire, and voila !!

again remove the xtal and caps ZC39, ZC39, resistors ZR24, ZR78, Jumper ZR78, and connect the 100 ohm resistor to the left hand side zy1 pad input of the xtal, as your facing the front of the machine, front to back.

I hope this helps anyone else trying to do a clock mod to this machine.

thanks Jim for all your help. your clock sounds great!

MC