LeCroy LT264M repair, does not power on. Update: powers on but broken trigger

[shakalnokturn]

Correction: The voltages to expect after 18IC3's buffer Op-AMP's are in the +4V to -4V range the ones stated previously are at the MST429A after the level shifting resistors.

I suppose you do get inputs to MST429A "CHx TRIG" and "CHx VAL" when trigger is set correctly.
Have you looked at MST429A pins 98&99, 93 for an output?

[Jontm]

Again, thank you for all the valuable information. I am working though your suggestions one by one and trying to test as much as possible of the different options.
From what i am seeing so far, 16IC6 looks to have sensible signal levels and activity both in and out, just not on INTLV CAL. I have yet to try to decode the if INTLV CAL should be on. This is on my todo list as it will require me to perhaps solder in some test leads, i am a bit short on hands It might well be that INTLV CAL is not used at all on this scope during normal operation for all i know.
Yes, ext trigger is also dead. I have checked 18IC3 and it looks good to me with values in the specified range.

As for the front panel calibration out, everything looks to be working correctly with all different frequencies and amplitudes.

I am having a hard time picking up any signals on the CHx VAL lines, even when i feed in the calibration signal. I have not been able to pick up anything at all for now. I am finding this a bit strange, but not quite sure what signal levels to expect. As for the CHx TRIG, i am able to pick up signal being toggled here during the auto calibration, but nothing other than that.

I will tru to probe the MST429A pins 93, 98 and 99 as you suggest next.
I also found what could look like a leaky capacitor 21C46, picture attached. Do not necessarily think that this is part of the problem as this is one of several on the -5V rail. I have measured this rail earlier to be correct, at least the voltage is. I will however try to replace it at some point.

[shakalnokturn]

Your capacitor looks more like having solder flux residue than a leak.

I'm puzzled to why you'd see "CHx TRIG" change during auto cal. but not during normal use...

Maybe It's worth starting a little closer to the signal input?
Let's assume you're troubleshooting on CH1, input a known signal to your LT264 on CH1 close to full vertical scale and confirm that the displayed waveform has correct amplitude with another scope.
Set the trigger source to CH1 and level so it's around median of your input waveform also set trigger to AUTO.

If I read SM correctly you should have in the range of 250mV peak at 2IC4 (HTR420) pins 29 and 30 (500mV differential) at this point it is still analog.

Can you confirm that you get no toggling  on 2IC4 pins 11, 12, 14, 15 outputs?

[Jontm]

The signal level going into HTR420 (pin 29/30) looks correct. I get 500 mV peak to peak on each of them with the cal signal (verified that this is correct with a separate scope) and setting the range so that i maxes it out.
Pin 11/12 have a steady -2.2 V DC. At boot during calibration it goes from 0 V to -1 V and then to -2 V and get stuck there.
On pin 14/15, the signal is at a steady -1.85 V DC. At boot during calibration it does switch a couple times between -1 V and -2 V.

If this is not how HTR420 should behave i am a bit surprised that all of the HTR420's act the same. It is not that many things that are common between them.

[shakalnokturn]

Measured inputs sound good, I'm assuming that the trig outputs are good enough too as their levels do cross typical NECL input thresholds.
Although I'm not sure what the serial bus on the HTR420 is used for (I don't know if it can inhibit trigger outputs preventing a new trigger sequence if the trigger signal is lost further down the way) it is one of the things that's in common with all HTR420's but also with other functions like HFE428's and FE relay switching.

I'm also thinking the same, odd that all inputs should fail trigger when there is not that much in common.

Next points I'd test are:

+/-5V supply rails at the HTR420 pins.
DC voltage variation at pin 32.  Should be in the +/-680mV  range (possibly as low as +/-500mV) and vary while adjusting the trigger level for the selected channel.
Consistency of "FE SRCLK", "FE SRDAT","CHx FE LD","CHx HTR LD" lines.

I wouldn't bet on the first three as they would likely also cause other problems than just the trigger. The "CHx HTR LD" however are dedicated to the HTR420's only.
CH1-4 have a common origin in 20IC4, unfortunately "EXT HTR LD" comes from a different 3 to 8 line decoder 20IC6.

However a stuck-low output on 20IC5 pin 15 would cause all five "xxx HTR LD" to not change, it would also cause "CAL LD" to not change which would in turn cause "INTLV CAL" to not change... So definitely worth keeping an eye on 20IC5 it all seems to point that way!

[Jontm]

I really appreciate the input on this, thanks again.
Unfortunetly 20IC5 pin 15 has activity on it and there is more activity when i change around the trigger and such. It looks to me like it is working as intended, really good idea though.
I am having a hard time imagining what could be wrong at this point. Everything is measuring ok. The +/- 5 V supply rails for the HTR420 looks ok. I will try to measure the rest of the FE SRCLK and FE SRDAT lines tomorrow.

Pin 32 is at a DC level that have a range of 300 mV to 600 mV, depending on the trigger level. There are however quite a bit of noise. If i am set to single trigger or normal, then the noise is about 100 mV or so. In auto, it is up to 500 mV or more. There are also a noise spike that corresponds to 32 kHz (300-400 mV spike every 31 us or so). Don't know if this is to be expected, but that is at least what i measure.

I have also gone over the board today on both sides with a thermal camera to look for failed capacitors and such without any obvious things showing up.

I think i will order some more memory to try out as well, it seems that the memory i put in is only rated at PC100 and not PC133.
One other thing that i want to try out is to reflash the firmware on it. Would it be possible for the memory issues to cause some data corruption on the firmware ? As mentioned earlier, the scope crashes every time i hit the "pannels" button as well. Seems like it cannot reach some address or something. Locks up and requires a reset.
I was hoping to reflash it today using floppy disks, but unfortunately it looks like the floppy drive is bad also (seems like a common issue). Will try to get hold of a GPIB cable from work tomorrow as well.

[shakalnokturn]

I'd definitely expect HTR420 pin 32 to be able to cross 0V when adjusting the trig. level (unless I'm confused and "CHx TRIG LVL2" is the main trigger and "CHx TRIG LVL1" is unimportant for basic triggering, still I wouldn't expect all that noise).

If you look back at sheet 18 (DC GENE) the "DCG CHARGE" is stated as having a +/-4V excursion, that is muxed by a couple of 4051's then buffered by TL084's and finally brought to adequate levels with a resistive divider before the MTR420's.

100mV noise (be it peak, p-p or RMS...) sounds atrociously much too much. Maybe it's worth working through the path from "DCG CHARGE" to see if something is wrong on the way.

Once you've checked that and the three serial bus lines to the MTR420, I'm out of ideas.

The firmware refresh could be a good idea, hard to decide if a corrupt/wrong firmware is causing the problem or if a hardware fault is causing the software to hang...
I don't know if it is possible to update a WR2 with a WR1 firmware and get into strange situations either...
ISTR there was a CRC check tool on the groups.io "LecroyOwnersGroup"although I don't remember if it was used for all LeCroy DSO firmwares.

[Jontm]

HTR420 pin 32 will cross 0 V and turn negative if i increase the trigger no near the maximum level. Then it suddenly flips and turns negative. Maximum negative trigger level is still well in the positive numbers.
As for the noise, i think that some of it might be a case of bad probing. I seem to pick up a lot of high frequency stuff in the ground lead for the probe. Tried again with a probe ground spring and got much lower values in the 50 mV range, probably some of it is still radiated noise. With just a ground lead on the probe, i get up to 700 mV (about 50 mV or so with the ground spring on the probe) noise spikes on the +/- 5 V rail. Unfortunately it is a bit hard to get to some of the probe points with the ground spring setup.

I am getting close to giving up on it, but will try to reload new firmware on it and also try a new stick of RAM once that arrives. This is a bit of a mystery to me as well. The time i have spent on this i probably would be better of just throwing it away and by a cheap rigol scope or something. I do appreciate how snappy it feels compared to some of the Tektronix scopes i am used to from work and it seems to have much more features as standard as well.

[Jontm]

Another ting i find a bit odd after some additional probing is that pin 1 on 2IC5 (3IC5, 4IC5 and 5IC5) never goes high, at least duing auto cal at boot. I guess that is intended behavior ? I guess that it makes sense, seeing that it seems like this cal signal is not used, at least not for power on self test or auto cal.

[shakalnokturn]

HTR420 pin 32 will cross 0 V and turn negative if i increase the trigger no near the maximum level. Then it suddenly flips and turns negative. Maximum negative trigger level is still well in the positive numbers.
As for the noise, i think that some of it might be a case of bad probing. I seem to pick up a lot of high frequency stuff in the ground lead for the probe. Tried again with a probe ground spring and got much lower values in the 50 mV range, probably some of it is still radiated noise. With just a ground lead on the probe, i get up to 700 mV (about 50 mV or so with the ground spring on the probe) noise spikes on the +/- 5 V rail. Unfortunately it is a bit hard to get to some of the probe points with the ground spring setup.

I am getting close to giving up on it, but will try to reload new firmware on it and also try a new stick of RAM once that arrives. This is a bit of a mystery to me as well. The time i have spent on this i probably would be better of just throwing it away and by a cheap rigol scope or something. I do appreciate how snappy it feels compared to some of the Tektronix scopes i am used to from work and it seems to have much more features as standard as well.

Did you mean:
"HTR420 pin 32 will cross 0 V and turn negative if i increase the trigger no near the maximum level. Then it suddenly flips and turns positive. Maximum negative trigger level is still well in the positive numbers."?
In any case I can't make sense of this, can't see how things should work that way...

Hopefully the firmware refresh will get it back on track, they are nice scopes when they work, plenty of features even without software options enabled.

Another ting i find a bit odd after some additional probing is that pin 1 on 2IC5 (3IC5, 4IC5 and 5IC5) never goes high, at least duing auto cal at boot. I guess that is intended behavior ? I guess that it makes sense, seeing that it seems like this cal signal is not used, at least not for power on self test or auto cal.

It at least fits with "INTLV CAL" not being active either, whether it is supposed to be that way or not is still uncertain...

[Jontm]

No. Maximum negative trigger (- 2.5 V at 0.5 V per division) is at about 324 mV, then it increases with increasing trigger level until it reaches 600 mV at 2 V trigger level (0.5 V/div). At 2 V trigger level, pin 32 will suddenly flip to - 735 mV and increasing the trigger level to 2.5 V will increase the voltage at pin 32 to - 700 mV 

Sounds a bit stange to me, almost as if there is an offset error somewhere for the trigger level ?

Did the reflash of the firmware, unfortunately it did not fix the issue. I am waiting for a new PC133 stick of ram to replace the PC100 that i use now, maybe that can make an impact, but i have my doubts.

Another thing that have bothered me is the fact that if i hit stop on the trigger control, time controls do not do anything. I can adjust V/div, but adjusting s/div does nothing. I can see the s/div changing, but the graph is not changing Is that normal behavior on LeCroy scopes ? The scope would be almost usable if i could just trigger manually by hitting stop and using the relatively decent memory depth to zoom into what i am interested in...

[shakalnokturn]

That's clearer thanks.

There is a problem to solve.
I've opened my (working) LT and checked a few points where it was convenient to probe.

Set to 1ms/div, 1V/div, auto, edge, DC, pos.

Measured "CH1 TRIG LVL1" at 2R105 coming from 18IC10 before resistive divider.
Trace centred, trig level 0V. : +66mV
Trace centred, trig level 4V (end of graticule): +1.55V
Trace centred, trig level 5V (maxed out above graticule): +1.92V
Trace centred, trig level -4V (end of graticule): -1.41V
Trace centred, trig level -5V (maxed out below graticule): -1.78V
Trace offset +2V, trig level 0V: +810mV
Trace offset -2V, trig level 0V: -670mV
There's no sudden jumping around, unless the auto recalibration kicks in, no nutty flipping negative when adjusting upwards...

Second reference voltage "CH1 TRIG LVL2" can be varied a little (measured at 2R107) by setting trigger to "window" and adjusting window size.

On the output side of things:
Idle (untriggered) voltages are -0.92 and -1.7V although I didn't check which is _OUT1 v.s. OUT1.
"CH1 TRIG" changes state when the trigger level is adjusted to a level that allows to trigger.
"CH1 VAL" will kick-in as well as "CH1 TRIG" when scope triggers using the window trigger.

Try working back from "CH1 TRIG LVL1" to find where things go wrong. I'd give the whole DC GENE bunch a reflow starting with 17IC1.
If you don't get to the bottom of things you should be able to use your trigger by removing the erroneous "CH1 TRIG LVL1" and feeding in your own variable reference, of course the scope will still fail self test...

Supposing that the panel menu hang is not related to the trigger problem, I'd check if it will also crash when accessing the "mass storage utilities" menu.
If it doesn't, look towards RTC and SRAM on CPU board, re-check for oxidization there at component pins. Maybe worth swapping the SRAM I.C.

If you stop the acquisition you can't expand the capture directly by changing time/div, you have to go through the magnifying glass function...


Edit: I forgot to mention that there's no obvious noise on "CH1 TRIG LVL1".

[Jontm]

Wow! Thank you. This is immensely helpful.
To put tings into perspective, i measure about 3.1 V at 2R105 when the trigger level is set to 0 V with the same settings. From there in keeps increasing as i increase the trigger level before it wraps around to negative.

Trace centred, trig level 5 V: -3.8 V
Trace centred, trig level 4.1 V: -3.9 V
Trace centred, trig level 4 V: +3.8 V
Trace centred, trig level 0 V: +3.1 V
Trace centred, trig level -4 V: +2.4 V
Trace centred, trig level -5 V: +2.2 V

There is certainly something wrong here. Based on this, it makes sense that the scope does not trigger. The measured trigger levels are set so high that even at -5 V set trigger level, i would need a voltage probably in the 6-8 V range. That being said, i was still not able to get it to trigger even if i applied a 15 V signal. The front end would probably start clipping at those kind of levels i would guess. Maybe i have so much offset in the trigger level that the front end start clipping the signal before i ever reach the required signal level to make the scope trigger.

I guess that i need to digg more into the DC GENE circuitry and the output from 17IC2. Perhaps identify the part of the muxed signal that corresponds to the trigger level(s) and check if it also have a significant offset in the output from 17IC2. 20IC1 could also be interesting as it adjusts the DCG offset voltage and DCG gain. In theory it should be possible to adjust the DCG offset in software (if that possibility exists in the service menus), but i will not start messing with that yet as the potensial offset error is so large that i have i hard time imagining that it is just a matter of calibrating the DCG offset.

I guess that i would need to decode the signal going into 17IC2 in order to actually check and if needed adjust the offset as it would be hard for me to know if there is an actual offset error from the IC without knowing what voltage is commanded over the digital input. That being said, i could probably assume that the digital bit is correct for now.

I think i have some work ahead of me Again, i am really grateful for these measurements. It seems like this could be a major step into figuring this out. Once i have gone over all the remaining tings that i want to probe on these chips, i will do a quick reflow of them, just in case.

[Jontm]

I have attached pictures of what becomes "DCG CHARGE" with trigger level:

-5 V
0 V
4 V
5 V

This is on 17IC2 pin 3 (VOUT). This is a +/- 10 V signal that goes into a inverting op-amp with a gain of 0.4.

I have made a red circle around what i think is the signal that corresponds to the trigger level ch 4 (i have used ch 4 as it is more easily available for me to probe).
As shown in the pictures, this strange trigger level with the large offset comes directly from 17IC2.
It seems like a bit of a hassle to probe the 16 bits that goes into 17IC2 (DAC712UK) to be able to compare the set voltage with the measured voltage out of 17IC2.
Without probing the digital signal going in to 17IC2, i find it a bit hard to tell if the offset on 17IC2 is wrong or not. Since it seems like the signal will just wrap to a positive value (as measured before the inverting op-amp) if the signal exceeds - 10 V. The signal seems to be centered well around 0 V at startup at least (offset of around 20 mV or less).
As strange as it sounds, it almost looks to me like the offset is in the digital signal as well. I guess i need to try to decode the DCG telegrams going into 17IC1 to be sure.

[shakalnokturn]

If you have selected the right portion of the "scanning" DAC's output sequence it does indeed look as if the problem is already there that far back.
Good idea to check on "DCG OFFSET", easier to get out of the way before moving on to the digital side of the DC GENE section.

I don't know about the 17IC3, 17IC4, 17IC5, 17IC6, 17IC7B portion: It is used to detect the probe identification resistor on the sense ring and channel 50ohm input overload but could also be used to setup "DCG OFFSET" by selecting one of the grounded inputs on 17IC3 or 17IC4 then searching the comparator switching point that is then reported back to the 17IC1 microcontroller. Keep those two 4051's in mind if you do find that "DCG OFFSET" throws the trigger control voltages around.

I also agree that it's tempting to come to the conclusion that the digital side is working if no other scope functions depending on the scanning DAC are experiencing erratic behaviour.
The digital side could be electrically sound but have the wrong data sent to a DAC because of a corrupt EEPROM.

[shakalnokturn]

Here's a .zip full of screen dumps from my LT354 if that can be of help investigating.
If you spot trigger related values that are way-off you could try modifying one channel manually for the sake of it. I'd advise to save a copy of the original cal data first.

Have you tried hitting the "UPDATE ALL ITEMS" contextual menu when you're in the "CAL ITEMS" menu? Does that result in a trigger error?

[Jontm]

Thanks again. These could prove very valuable for further analysis. I just did the same measurements and are in the process of comparing the values. I will probably spend some time converting everything from HEX and putting it in a excel sheet together with my measurements to get a clearer picture of everything.
Yes, i have run the "UPDATE ALL ITEMS" command in the "CAL ITEMS" menu. I fails on the trigger level just as it switches over to the trigger test. Then spends some time with testing trigger before it beeps and say NG on the trigger.
I does look like the HTR420 trigger test is able to pick up anything ? Results in a gain number of 6000. Slope+ is at 71535 and slope- is 6000. Same for all channels (some have slightly lower gain).
There also looks to be something strange with the measured trigger hysteresis. In the hardware register "Trigger Hyst B" and "Trigger Hyst D" have a "voltage at output" value at just over 7 V. "Trigger Hyst A" and C is at some impossibly large number. I have measured the actual signal to be about 2 V at 5C94 for all channels. That sounds about right, based on the register value for the signal going into the DACs. On pin 34 of the HTR420 i measure about 2.6 V for all channels.

I did do some more digging on the probe identification circuitry i actually fond a bad contact between the probe detection ring and the main board. There is a small gold spring that touches a pad on the board of all the different channels. Two of the channels had some soot on the pad, creating a bad contact. That should however only affect the probe detection functionality from what i can tell. I cleaned the pads with some contact cleaner and now all the channels are able to detect probes properly. I measure 4 V on the probe rings, guess that should be about right based on the schematics.

I have also done some calculations on the signal controlling gain and offset for 17IC2. The values i measure going into 17IC2 matches the calculated values based on the values from the registry regarding the digital signal going into the DAC (20IC1). I belive now that gain and offset is set correctly. It is the digital signal going into 17IC2 that is strange.

[shakalnokturn]

Just a thought trying to link the two problems your scope has:
Of all the calibration values I have no idea which are factory set with "LeCalSoft", and what is able to update automatically during normal use to compensate for temperature drift.

I don't know either where that data would be stored, if it is split into several locations or redundant.
There is an EEPROM on the acquisition board, and SRAM enabled through the RTC on CPU board.

If you suspect that the wrong data is being loaded to the scanning DAC (which is looking more and more likely), and considering that the scope hangs when you go to the "Panels" menu (which I can only imagine are saved to SRAM).
I've never heard of a LeCroy DSO go out of calibration because of a dead RTC battery which also maintains SRAM data so the factory calibration won't be stored there.

It could be that on boot the factory cal. is read from acquisition EEPROM, copied to SRAM and used from there.
Maybe a bit far fetched but not absolutely impossible.
SRAM would also be a good suspect because the scope was "exposed to the elements" and as long as the battery was charged the SRAM was powered making humidity a more destructive hazard.

[Jontm]

The whole thing with calibration seems a bit strange on these scopes. I don't know how much factory calibration there really is on these. It almost seems like it measures and calibrate most if not all of the cal parameters itself. Looking at the replacement procedure on the main board, it just states that following a main board swap, one need to run the "Measure board items" and the "measure overload" functions and save them to EEPROM. There are mentions of manual main board adjustments, but i assume that is the adjustment of the potmeters on the board and such.
The "measure overload" function is a bit interesting. I don't know what it does, but i guess it is not too far fetched to think that it might check some ranges and offsets.
Right now i have the scope in 100 prices as i thought it would be good to have a quick look at the power supply as well, but once i have put it back together i will definitively try to run the "measure overload" function and try to investigate what it does and if it could potentially change anything about the big trigger level offset error that i have. Maybe the information that "measure overload" acquires is corrupt or missing. I see from the cal registry that it does look like all the channels are missing hysteresis data.

One thing that i do however find interesting is that during the initial calibration at boot, it looks like there is no offset to the trigger level control signals. It might also be that the offset is a result of the failed trigger calibration, but i have to think about this a bit more if this is a possibility. On second thought, it would be interesting to scope both the signal into HTR420 and the trigger level at the same time during calibration. Signal levels should be fairly similar and that should allow for me to confirm if the HTR420 should trigger or not. Another thing, is it to be expected that the voltage going into pin 34 is as high as 2.5-2.6 V ? I am a bit confused as all the other analog signals going into the HTR420 is scaled down to +/- 600 mV range. As someone that are more used to working with kV's and MW's, i am a bit behind on my circuit analysis theory I cannot seem to understand how i can judge how the voltage is scaled by 2R110, 2R109 and 2Q12. More used to transistors used as switches and not as amps

I have looked at the circuitry around the RTC circuit and what i assume is the SRAM. It looks to be in good condition at least visually. Even though the scope was exposed to the element (inside a shipping container), it looks to be in very good condition. The only thing that i have found so far that is a bit concerning is that some of the exposed gold/copper traces have partly corroded away some places. It does however looks like there is no broken traces, it is mostly the exposed shielding traces that are corroded. Other than that, it is things like a little-bit of dust/mold in the fan inlets/outlets. That is however mostly sorted at this point.

[shakalnokturn]

Did you get any further on this?

I'm working on a long repair project a Tek TDS620 that has suffered from the usual SMD electrolytic havok and experiencing similar issues. Some of the FE analog control voltages are missing, I've double-checked the DAC is working, tested track continuity between there and analog MUXes, replaced a couple in doubt, no better so I'm pretty sure the corresponding data is lost before on the CPU board, just finding where is a nightmare...

As for your LT's hysteresis control on pin34 of HTR420 I'm not sure what to expect either the output from DAC is in the 0-4V range, I'd expect the scope calibrates the hysteresis control level itself, anyway as long as it's mot trying to exceed the +5V to the HTR I'd call it good.

[Jontm]

Sorry for the late response, been away on holiday. I am planning to start to work on the scope again in the coming weeks, will let you know if there is any updates in case it might be of interest to you or others having similar issues. I am still stuck with not being able to trigger and the strange offset on the trigger control voltage on the DAC output.
Tried to change the RAM sticks again and run the measure overload routines and similar without any improvement.

[Jontm]

I have to say it would be very interesting to know the purpose of the 16IC8 and the whole circuitry creating "CHx CAL SIGNAL".
Have tried to trigger on these signals and i am not able to detect anything on either of these no matter what calibration sequence or "measure overload" sequence i am running from the service menu.
I mean, it surly have to have a function right ? Could it be that this circuitry is used for the trigger calibration, hysteresis and possibly the adjustment of the DCG trigger control voltage that are off ?
I feel a bit stuck so it is probably worth to check out further i guess.

[shakalnokturn]

I'll try to remember that and see if I can get a few captures next time I have an excuse to open my WR2.
No idea when that will happen, I'm not finding much time or motivation for electronics lately.

[Jontm]

I think that i have found a situation where "INTLV CAL" goes low and i guess that 16IC8 AD9850 should be active.
In the trigger calibration/adjustment menu, there is a "ODP/EVT/HYST auto adjust" button. This starts calibration routine that activates the "INTLV CAL". This routine seems to get stuck for a while at "Incomplete RIS acquisition 1 of 50" before it continues and stop. When this routine runs, it seems like that the circuitry around 12IC5 is active and a 125 MHz signal goes into 16IC8 (AD9850), the signal is however very weak. See the attached scope pic. If i read the datasheet correctly, the signal going into the AD9850 should be a CMOS level signal and i would assume that a 4 V signal with a 50 mV 125 MHz signal would not be sufficient ? There is also so signal out of the AD9850. The voltage rails for the AD9850 and the reset looks to be correct so my theory is that either the 125MHz CLK signal is too low amplitude or the AD9850 is bad (or both).
My next plan to start to analyze the circuitry that i assume should convert the ECL signal from the MC10EL33 to a CMOS level signal. To be honest i find the circuit a bit intimidating, but i guess i can just start to try to measure diodes and shorts on the transistors, diodes and capacitors in the circuit. Hopefully one of these will have a clear indication of a fault. If not, i may try to change out the MC10EL33 since i already ordered a couple of those a while back in case they were bad.

[Jontm]

I am struggling to find the component that cause the low signal level, but according to a application manual i found on the AD9850, the clock signal should be much higher.
"Proper clocking of the AD9850 occurs when the signal is at least 3 V p-p and centered at VDD/2.", https://www.analog.com/media/en/technical-documentation/application-notes/AN-419.pdf
I will have to double check that i have not done something stupid like set a bandwidth limiter on or choose the wrong probes, but as long as i am probing this correctly and only getting like 50 mV amplitude on the 125 MHz signal, i think that i might be on to something that could possibly cause the issues that i am seeing.