Author Topic: Rohde & Schwarz SMIQ03B with Error 110 Output unleveled; IQMOD: ALC failure  (Read 14751 times)

0 Members and 1 Guest are viewing this topic.

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Yep, that was the video that I watched before bidding on this unit. He replaces the final output device, which did not fix the issue on my unit. I'll be replacing the two drivers before that final device after I get the parts from Germany.

Final device is a SHF-0189, purchased from link in the i-hobby video shown in the previous message, but can also be found on eBay.
The two drivers in the chain before that are SHF-0186 devices, currently available on eBay from seller "rici61".
« Last Edit: July 11, 2020, 10:14:42 pm by zmetzing »
 

Offline smgvbest

  • Supporter
  • ****
  • Posts: 623
  • Country: us
    • Kilbourne Astronomics
Did you check out the repair that DaJMasta and I did.   there's allot of information in those posts
I also produced a spreadsheet to record all the TP's in the diag section to help zero in on the issues.
you would just run your's up to the 3Ghz instead of the 6Ghz we did

this is DaJMasta
https://www.eevblog.com/forum/repair/rohde-schwarz-smiq06b-repair-log-6ghz-board-alc-error/msg1193985/#msg1193985

this is mine posting
https://www.eevblog.com/forum/repair/rohde-schwarz-smiq06b-repair-6ghz-board-level-preset-error/msg1240640/#msg1240640
Sandra
(Yes, I am a Woman :p )
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
I did check out those posts and they were very informative. I'm keeping my eyes open for a 6GHz extender board and the FM modulator board (although this could be done externally by feeding the proper I/Q signals).

I await the SHF-0186 devices from over the sea, and then I'll remove the 100 tiny screws from the IQ Modulator board again. :-)
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Well, the entire output stage has new amplifiers, but this was not the problem. So, I've stopped shotgunning it and started tracing the signal path.

I performed the CW leveling procedure IQCON 7.4.4.4 and found that the output from that module was ~2dB low. That has been rectified, but that wasn't the issue, either. Note: The SMIQ03 will run without the IQMOD module installed ("Press SELECT to simulate hardware"), so that R495 can be accessed when the front panel is removed and rotated out of the way. I have my SMIQ on it's side, which seems to work the best for keeping things out of the way but still accessible.

I then traced down the signal from the input connector X247 (FIQFIL) [schematic page 17] toward the FAM3300 off-page arrow. I see the amplifiers doing their thing along the path, with a selected frequency of 450.1 MHz and +13dBm selected. My analog o-scope only goes up to 470MHz, but the levels seem reasonable until I hit the Pi-attenuator R966/R120/R113. On the C593 side of things, the signal looks great (1.070V or 4dBm, just what we expect). On the C343 side of the path, the signal drops to something very low, and doesn't look like the 450.1 MHz signal I was tracing. I found R966 to be 51 Ohms, R120/R113 to be 100.0 Ohms, and there was a C590 piggy-backed across R966 which seems to be 1pF. This does not agree with the 1084.9800.01 schematic, but my board has a .08 revision, so maybe that's ok. This would be a 8.5dB attenuator, without the effects of the capacitor, which would allow a high-frequency bypass path for better leveling, perhaps?

I went ahead and replaced R966, but no joy. I can only think that something with the D_SWITCH circuitry is effectively grounding out the signal.

Next, I plan to lift C343 and see if the problem persists, to better isolate the problem.
« Last Edit: August 15, 2020, 05:02:43 pm by zmetzing »
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
I've repaired two SMIQs with that same error and the problem(s) were always caused by either RF amplifier(s) (MMIC or final FET) and RF switches (old Hittite parts). It seems R&S decided to drive the control voltajes a bit harder to improve isolation between ports, which has an impact on the part's life. I replaced them with something similar and modified the resistor networks to trim the control voltajes down to safer levels. I believe I have some of those parts still somewhere...

I seem to have the same issue with the switch S2 (SSW124). I removed C343 and observed a reduced amplitude, but still good, 450.1 MHz signal on the hot end of R113.

Replacing C343 and then breaking the signal path at C333, terminating that leg into a 47 ohm resistor, results in a garbage waveform of not much amplitude on R113. So, it looks like S2 has bit the dust. I'll be PM-ing you, EB4EQA, to find a suggest replacement part.

Postscript: Doing the math, I see that R&S is putting nearly -10V on those switch inputs, which are nominally -5V. I may increase the value of R36 substantially, perhaps to 4.7k, to reduce the voltage on those lines to something closer to -5V. Any thoughts?
« Last Edit: August 15, 2020, 08:43:47 pm by zmetzing »
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
I've made a first-order identification of a part which might work: HMC284AMS8G HMC270AMS8GE

Differences:
  • The package is smaller -- not a deal-killer
  • RF input pin is on wrong pin -- solvable with small wire
  • Control inputs on wrong side of chip -- annoying, still solvable
« Last Edit: August 15, 2020, 07:57:24 pm by zmetzing »
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Appears that others have gone the same route with the HMC270 device:

https://www.eevblog.com/forum/repair/rs-smiq-ssw124-gt-hmc270-replacement-(_alc-failed_-error)/

Thanks, Roberto, for the helpful information!
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
I replaced S2 (SSW124) and boy was that a bear. Another situation where hot air plus the Metcal got it out without damaging the board. Definitely not for the faint of heart. Note: In the pictures, I swapped the control lines, which was wrong. The lines should go straight across (2nd pad to top left pin, 3rd pad to 2nd left pin) for the RF to be routed properly. I didn't take a new picture, but you get the idea.

Partial success! The message "ERROR: CW: ALC_ON voltage oot" is no longer generated, and 7.4.4.5 test point 2108 is now ~3.3V, P54 is ~2V. I can trace the signal all the way to V144.

However, I'm now getting "maximal level oot" from the calibration routine, and the bias on V144 looks all wrong. The manual says the drain should have ~4.5V, whereas I'm measuring ~1.2V. Definitely not going to work very well without some more drain voltage. Drain current appears to be set by V6 (BSP31 device) along with some circuitry around it. I'll have to confess that I'm not quite sure what it is doing .. I'm not an analog engineer. V143 is a 5.1V Zener reference, R1301/R14 combine to a 14 ohm resistor, but I don't see what it's actually doing.

Note that I replaced this device with a "new" one from an eBay seller. I wonder if it is toast and drawing too much current from the current source (if that's what it is). I may try replacing it with the old device.

P.S. I replaced R1151 and R1150 with 1.5k resistors to decrease the negative voltage on SWITCH_A and SWITCH_B. The HMC270 part cannot tolerate much more than -5V.

P.P.S. You'll note that I didn't reconnect the signal path after putting the new switch in. Limiting the causes of down-stream failure is always a good thing when replacing components.
« Last Edit: August 19, 2020, 06:30:40 am by zmetzing »
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
"That's no small moon."

On the path toward a working SMIQ, we last learned that the bias on V144 was wrong.

While probing around on the bias circuitry, I found 0.8V at the junction of V143 (5.1V Zener) and R644. As the +7V5A rail was at the proper voltage, I was very suspect of the diode, and with good cause. Examining the diode under the microscope, I noticed that the cathode band was pointed at ground! This is definitely wrong. Also, it looks like this device was re-worked at some point, possibly in an attempt to fix V144.

I found a replacement 5V1 Zener in my SMT parts bin -- the last one in a lone ESD package, picked up by chance from someone dumping a load of remnant board build kits. It is a little lower wattage rating (375mW), but the bias circuit isn't drawing that much current (~40mA). Fitting it in, the bias on V144 is now correct, and it appears to be amplifying!

The LEV PRESET calibration gets a little further, but still no joy. The new message is "nominal level oot", which is different from the "maximal level oot" that I was getting before this fix.

We continue to follow the signal ...
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Getting very close here, folks. Re-reading the service manual pointed out that I should close up the resonator chamber M while running the bare board. Given that I don't have a cover handy, I re-installed the B-side shield with two screws over the M chamber and four in the corners.

With Level 2 Debug ON, CALIB -> LEV PRESET gets to the full bar graph like it will complete. but then says "maximal level oot" and the debug info says it failed at 2.8GHz. So, perhaps still not quite enough gain at the high end?

P.S. Telling the unit to "Continue calibration on errors" seems to get it through the CALIB -> ALL path, and the 110 error disappears! However, the IQMOD-CW LEV PRESET table definitely shows a trend on the high-end toward +128 numbers, which appears to be the maximum. Does that mean it was trying to add power (reduce attenuation) at the high end?

I'm considering changing R1226/R411, which are currently selection II, to selection III (edit:corrected). That should boost the overall gain of the final PA.

Would anyone be able to post a picture of their IQMOD-CW LEV PRESET table, specifically the > 2.2 GHz frequencies?

P.P.S. Even though my unit shows a front panel of "SMIQ03B .. 3.3GHz .. 1125.5555.03", attempting to enter a frequency over 2.2GHz (with no errors present in the system) says "Out of range". Did someone sell me SMIQ02B innards with a SMIQ03B nameplate? Or am I missing a setting?
« Last Edit: August 20, 2020, 07:54:28 pm by zmetzing »
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
P.P.S. Even though my unit shows a front panel of "SMIQ03B .. 3.3GHz .. 1125.5555.03", attempting to enter a frequency over 2.2GHz (with no errors present in the system) says "Out of range". Did someone sell me SMIQ02B innards with a SMIQ03B nameplate? Or am I missing a setting?

Well, it looks like I've been taken by an eBay seller who says "I’m pretty sure that gear run until 3.3 GHz", which isn't true of the SMIQ02B.

I doubt changing the batteries in the CPU unit would have caused it to suddenly think it is the lesser version.

Not sure if it's worth filing an eBay claim.

Anyone know if there's a way to change the model to SMIQ03B via software incantation?

 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Fixed (I think)! I let the unit warm up for about 30 minutes, then re-tried the calibrate without any debug options turned on. It completed successfully!

Now, if I could only figure out how to fix the bit-flip that made it go from a SMIQ03B -> SMIQ02B. The seller has pictures of the unit, complete with all the S/N and external markings, showing that it, at one time, went to 3.3 GHz.

What is the "Factory Installation Key" on the back? Would that turn it back into a SIMQ03B, if entered into the appropriate software or into the instrument itself?
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
did you ever managed to fix the 'IQCON no convergence' error?

Based on my experience, this is caused by a failed S2 (SSW124) on the IQMOD board (schematic page 18, PDF page 52). I got this when I had the SWITCH_A and SWITCH_B lines reversed, so it was sending the FAM3300 signal off to the wrong path.
 

Offline teknut

  • Contributor
  • Posts: 6
  • Country: au
Would anyone be able to post a picture of their IQMOD-CW LEV PRESET table, specifically the > 2.2 GHz frequencies?
Hope it helps if still required
 
The following users thanked this post: zmetzing

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Thanks! Could I beg another couple of screen shots for the IQCON table? Specifically, I'm interested in the values as they head toward 3.3 GHz.

I don't have my power meter hooked up, as the unit has a power supply problem. However, power appears to be approximately correct, given that I have 1 meter of RG-174 between the SMIQ and the Anritsu SA.

(That Anritsu will be the topic of a future repair, and possible custom TFT LCD upgrade!)

 

Offline little.tesla

  • Contributor
  • Posts: 15
  • Country: ch
What is the "Factory Installation Key" on the back? Would that turn it back into a SIMQ03B, if entered into the appropriate software or into the instrument itself?

The Factory Installation Key defines/enables the model (e.g SMIQ03, SME03 etc) in the software, since the software is generic for all generators SME, SMT, SMIQ (exception is the fast CPU option). To my knowledge it's entered after a blank software install. I don't know if it can be changed once entered or how it's entered. Hope this helps a bit.
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
Quote
The Factory Installation Key defines/enables the model (e.g SMIQ03, SME03 etc) in the software, since the software is generic for all generators SME, SMT, SMIQ (exception is the fast CPU option). To my knowledge it's entered after a blank software install. I don't know if it can be changed once entered or how it's entered. Hope this helps a bit.

Indeed it can be, and I thought about this around lunchtime. The trick is to unlock LEVEL 3 access, and then a new option appears under UTILITIES -> INSTALL -> FACTORY INSTALLATION KEY. Make sure to set "FACTORY OPTION TO INSTALL..." to SMIQ03B.

I now have a fully-functional SIMQ03B! Hope this narrative helps others.

(Now I have to eat some crow and apologize to the eBay seller for suggesting that he/she sold me the wrong unit.)
« Last Edit: August 24, 2020, 06:53:17 pm by zmetzing »
 
The following users thanked this post: little.tesla

Offline RecursiveLogic

  • Newbie
  • Posts: 4
  • Country: us
I've been working on a SMIQ 03 (non B) model. It's been interesting following your thread, and working parallel to your progress. Currently I am trying to resolve the issue with IQCON no convergence during calibration. The only error I'm dealing with is Error -313 Calibration Memory Lost; LEV PRESET run internal calibration.

There are some differences with the IQ-Modulator board... most notable S1 and S2 are populated with YSW-2-50DR. Has anyone else encountered these chips, and is the HMC270 a valid replacement, or am I better justified going with an M3SWA-2-50DRA+ as a possible recommended replacement?

I've also included an example of a previous repair made on the board, most likely to correct an Error 110, which I've had to fix for obvious reasons.
 

Offline zmetzing

  • Contributor
  • Posts: 34
  • Country: us
is the HMC270 a valid replacement, or am I better justified going with an M3SWA-2-50DRA+ as a possible recommended replacement?

The YSW-2-50DR looks to be logic-level control with 3.3V positive logic (0, +3.3), so the HMC270 chip, which uses 0V and -6V, would not be the appropriate choice.

The M3SWA chip looks like it would work, with a few flying wires, with the small caveat that it doesn't go all the way to DC (0.3MHZ or 300kHz). If the signal it switches stays above this lower limit, which it might if it's the first switch out of the IQCON block, it'll work just fine.

Good luck, and, yeah, it looks like someone tried to use a branding iron to install that transistor. :-)

 

Offline techneut

  • Regular Contributor
  • *
  • Posts: 61
  • Country: nl
I've been working on a SMIQ 03 (non B) model. It's been interesting following your thread, and working parallel to your progress. Currently I am trying to resolve the issue with IQCON no convergence during calibration. The only error I'm dealing with is Error -313 Calibration Memory Lost; LEV PRESET run internal calibration.

There are some differences with the IQ-Modulator board... most notable S1 and S2 are populated with YSW-2-50DR. Has anyone else encountered these chips, and is the HMC270 a valid replacement, or am I better justified going with an M3SWA-2-50DRA+ as a possible recommended replacement?

I've also included an example of a previous repair made on the board, most likely to correct an Error 110, which I've had to fix for obvious reasons.

Any luck with the "IQCON no convergence" error? I have SMIQ 02E with the same error and also the same switch. Unfortunatly is the board different from the SMIQ-03B so I can't use those schematics and testpoints.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf