Crystal Castles no 10MHz signal

Qolvc

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So I just got my hands on a Crystal Castles board for a Cabinet that I am restoring and am trying to work out the kinks with the board. So where it stands right now I am getting random garbage on screen. I am running it on a switcher for testing and am getting clean voltage across the board. Some of the things I already replaced were the 2 filter caps near the edge connectors and the 10MHz crystal. When I got the board the first thing my eyes darted to was the crystal because you could visibly see it rattling and pushing it with your finger you could hear stuff inside it shaking around so i replaced that before ever even powering the board. Now, I am pretty new to using an oscilloscope and I don't have the best one or anything but it's worked in the past so I am trusting its readings. So anyways, when I connect the scope probe all up and test the TP labeled 10MHz I notice that I am only getting around 13khz. So I was just wondering if anyone else has had the same problem or could give me a place to look. I'm not to familiar with clock circuits so hoping to learn a few helpful skills from this repair!
 
No. And after doing some further testing I actually stacked another 04 on top of that but I bent the pin 11 on that chip out to see if I was getting 10MHz when isolated from the circuit and was still getting 13khz so I think the issue might be before it outputs from the 04. Going to try and get some readings from the components that make the circuit up.
 
It would be good to test the crystal at its output directly rather than looking for a clock down the chain of ICs. That way you can eliminate the crystal being bad (I know that it is new but you just never know).

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Might be user error as the OP admits he's new to using a scope.
What scope is it? Analog digital? What's its bandwidth spec? What settings are you using? How are you attaching the probe? Did you check the probe on the CAL pin of the scope (I assume it has one)?

Alternatively, might be one of the passive components or even Q1 (2N3904) - I've seen those go bad.
10MHz should be observed at both pin11 (input) and pin10 (output) of 9M 74S04 inverter. Measuring at the base of Q1 might be inconsistent.

CC_Clock10M.jpg
 
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You want to be probing at pin 10 (not 11) of the 04 at 9M. As said above, you want to probe downstream of the crystal, usually at least one TTL chip away, not on the clock circuit itself.

If you have no clock there (and you've already replaced the crystal), replace the 2N3904 (Q1). If still nothing, replace 9M. All of these things can cause no clock. But that's about it, as there isn't much else (aside from having a cracked resistor or cap in the rest of the clock circuit. So check all of those by pushing on them sideways. If a component is cracked, they'll often split if you put side pressure on them. But a healthy part should be able to tolerate being pushed sideways a bit.

Also, make sure you have the correct replacement crystal.

1728428291251.png
 
Thanks for all the info, after replacing the Q1 Transistor with a suitable replacement I am now getting a solid 10MHz everywhere I should be. There are still a few things wrong with garbage on the screen but I assume a buffer is probably bad and that's unrelated to this thread. If it warrants a second thread I'll probably post something in a few days. Thanks!
 
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