Rohde & Schwarz SMIQ03B with Error 110 Output unleveled; IQMOD: ALC failure

[sorenkir]

Hello,
I have this generator with the error in the subject (no photos yet).
It is cosmetically like new, very heavy, built like a tank, but very high hour count: 88640h (10 years) and attenuator toggle count more that 10M!
The RF output is very distorted (seems like clipped and wrong amplitude).
I will soon try to find the fault with the help of the 4 Service Manuals found on KO4BB's Manuals Repository http://www.ko4bb.com/manuals/index.php?dir=Rohde_Schwarz
Unfortunately, these manuals are missing the schematics.
Does anyone have them or know where I could find them ?
Thanks,
Michel.

[rastro]

I have not seen any CLIPS for this unit in the public domain.  Have you try running the calibration routines in volume 1 of the service manual.  They will should provide error messages if they fail.  However you will need to first the first level password.  There are 3 levels of password protection for the SMIQ models.  They are as follows:
PASSWORDS
LEVEL 1      123456
LEVEL 2      250751
LEVEL 3      120155

There are also digital test points available at the user interface. 

-rastro

[sorenkir]

Hi,
Thanks for your help.
I have tried the test points of IQMOD, the only one to be out of range is 2122 (Control voltage burst element / Power Ramp).
Maybe related to back panel input "POW RAMP" ?
I will try to follow the path from this input into the IQ Modulator...
Michel.

[rastro]

Michel,

There is also a troubleshooting write up on an SMIQ06.  It's in German but you can probably pick and paste into google translate.
http://www.bymm.de/documents/27/SMIQ06B_6GHz-Modul_V1_11.pdf

-rastro

[sorenkir]

Thanks rastro, but this note applies to the 6GHz option board, which I don't have.
I will continue my debug but I'm afraid it will not be very easy: double sided board, no silkscreen, no schematic except the block layout on the cover and a short description in the Service Manual...

[rastro]

Michel,
I agree it's going to be challenging to troubleshoot.

There is also a users group you can try - although there is not a lot of activity (compared to the hp users group).
https://groups.yahoo.com/neo/groups/Rohde_Schwarz/info

Also the manual gives a parts list and X/Y coordinates in mm for components on the PCB's.  If I remember the (0,0) coordinate is lower left corner on the front of the PCB and mirrored for the back of the board.  At least it list might be helpful if looking up datasheets for the components.

-rastro

[sorenkir]

Thank you for your support!
First thing, I think, is to build an extender: DIN41612 Type B 64pins connectors male/female & flat cable + 2 x SMA-SMA cables + 1 x MMCX-SMB cable (why so many connector types on these boards: MMCX, SMA, SMB & SMC ?)
Then I will be able to probe the effect of this "POW RAMP" rear input which goes to an analog switch DG419. Maybe this switch has been damaged by an over-voltage on the input (no visible input protection on the board) --> measurement 2122 out of range, whatever value on the input.
To be continued...
Michel.

[sorenkir]

Troubleshoot Sunday !

No extender for the moment, so I took some time to watch Shahriar's excellent repair video of an Agilent E4433B which has an unleveled error:
https://www.eevblog.com/forum/testgear/video-teardown-and-repair-of-an-agilent-e4433b-esg-d-synthesized-signal/

It gave me inspiration and I examined the final stages of my SMIQ with more attention (and the help of the Service Manual).
It seems that the principle of operation is similar: one direct path above 450MHz and an heterodyne path below (LO @ 2.4GHz).
Then, the final stage is composed of one MMIC amplifier NLB-400 (marking N4) followed by the same HFET than in the Agilent: SHF-0189 (marking H1). The Service Manual says this final stage is made of 3 HFETs, so it must be a different hardware version...
The ALC detector is after this final stage.

By removing the front panel, I managed to gain access to the upper side of the board and have been able to probe the signal path: it appeared the signal which is correct up to the MMIC, is not amplified by the SHF-0189 but its amplitude decreases through it!
The bias on the input is -2.8V as expected but on the output, it's only 0.7V, when I was expecting about 7V. The bias chain, driven by a BSP31 transistor is only 1.5V at the starting point.
I removed the transistor and tried to power the HFET with an external power supply but when I injected 180mA, which seems an acceptable maximum, the voltage was clipped to 1.6V.
The BSP31 is OK but I think the SHF-0189 is defective.

Now I will try to find one, and then, the hard part will be to desolder the defective HFET, because it stands in a small cutout into the shield (see photo). If someone has an idea ?

To be continued...
Michel.

[rastro]

Michel,

Sounds like you made some very good progress.  The solder connection on H1 center pin looks a little questionable - but this could just be the picture. 

As far as removal:

I'd probably leave the shield soldered in place to avoid PCB damage.
Cutting H1 out and de-soldering remaining leads may be the best approach ... otherwise....
1. You are going to need a lot heat on that tab of H1 and its large pad.  Probably needs a direct solder iron connection using the largest a tip that will fit. 
You may need to apply hot air to the 3 legs at the same time - if you have equipment and hands.
2. I may also be good to mask adjacent components with Kapton tape to protect them from head or migrating if their solder gets too hot.

-rastro

[sorenkir]

Hi,

Thank you rastro for your advice.

The SHF-0189 I have ordered (to Utsource, good service, two week delivery from China to France) have arrived. I had ordered 3, just in case (which has proved to be a good decision)...

I managed to remove the defective chip with my dremel, did not succeed to completely desolder the ground pin, but I removed enough metal to be able to solder the new chip. I had to remove the shield above the IC, to gain access to the pins.
The first soldering attempt failed, I broke the case while trying to bend a pin.
I did a much better job on the second try, see photo.
It is not perfect, but it is not easy because of the very small size of the IC (~4mm width) and the adjacent components are very close.
I did not bother to rebuild the shielding.

And voilà: No more errors, self calibration passes, output signal is in spec.

Just the backlight intensity is a bit low, due to the high hour count. I can live with that, but if anybody has an idea ?

While the beast is open, I have moved the back connectors to the front: quite easy, all the cables, even the semi-rigid one can go back or front.
In the meantime, I have upgraded the firmware to the latest available version 5.93HX on R&S website (lost the self calibration tables in the operation, but not a problem now that everything works, it is rebuild in a few seconds)

You know what? ...   
Michel.

[rastro]

Hello Michel,

That's great news!  Thanks for posting pictures of the repair.  If you suspect any RF noise issues later you may be able to fill in the cut out shield by soldering in some thin copper sheet.  It's probably not an issue.

Regarding the display:
I saw some talk on the yahoo HP blog that someone successfully fixed his HP and RS system by replacing the Cold Cathode Fluorescent Lamp (CCFL).  Various sizes are available on eBay.  The CCFL inverter would be another candidate - universal replacements are also available.

Also thread in eevblog: https://www.eevblog.com/forum/testgear/rohde-schwarz-fsiq-7-signal-analyser-screen-not-working/

Regards
-rastro

[sorenkir]

Hi rastro,
You are right, replacement CCFLs can be found on the Internet.
Accessing the 2 CCFLs seems easy but requires to fully disassemble the display and I am not sure I want to disturb this glued ribbon cable...
Michel.

[rastro]

Hello Michel,

Yeah, they don't make it easy.  I would also be hesitant to put stress on the ribbon cable connection.  Those connections seem pretty delicate.  I appears you have to bend the tabs to remove the panel also. 

I'm not sure but I thought I saw some information that some of the models/units of RS displays are interchangeable.  Maybe a CMD test set that is obsolete.  I would probably be hard to be certain.

Regards
-rastro

[sorenkir]

Exact! I have a another german device (Wandel & Goltermann SF-60) that uses the same display, but it has a few black lines, probably due to the glued ribbon cable...
May be I will try to fix it one day, as Dave does in a video for a Fluke Scopemeter.
Michel.

[rastro]

Michel,

Good detective work finding a comprable display.  Too bad it's not 100%.  I saw Dave's video.  It was a good attempt but with mixed results - there has to be a better way.

Some further thoughts on display repairs:

1. I wonder if one of these "Home Sealing Impulse Heat Tool" could be hacked to reflow the solder or reactivate the glue on these troublesome LCD ribbon cables?  It looks like these have a heating element riding on a spongy heat resistant pad - so it may provide better contact with the faulty area.  The heat element is small enough that you could work on one area at a time.  They are certainly cheap enough to experiment with.  I have not seen anyone else try this - who knows...
Example:
Mini Bag Sealer Home Sealing Machine Heat Tool Impulse
http://www.ebay.com/itm/Mini-Bag-Sealer-Home-Sealing-Machine-Heat-Tool-Impulse-Food-Packaging-Fashion-/252052218343?hash=item3aaf7ba1e7:g:rhMAAOSw3ydVyBUh

2. If you go the route of changing the CCFL it may be possible to add a strain relief where the cable meets the PCB.  On either side of the cable there is a hole in the PCB.  Maybe a threaded hook on both ends to clamp down a metal strap and thin piece of rubber in contact with the cable. 

Still, you've made pretty good progress on this instrument!

Regards
-rastro

[jgorsk]

I also have a faulty SMIQ with the 110 error (Output unleveled; IQMOD: ALC failure) but the output stage amplifier seems to be working.
I suspect some filters between the frequency divider and tha output amplifier stage.

Attached are the spectra of the -10dB signal at 450MHz and 460MHz. The amount of harmonic tones at 460Mhz (and above) is way higher
than specified in the SMIQ documentation.

Could someone do me a favour and post the spectra of their SMIQ generator at -10dB and 450 and 460MHz please?
I'd like  to see how those signals look like on a working generator.

[rastro]

Hello jgorsk,

Which model of SMIQ do have (3,4,6??).  It will probably make a difference.  The 4/6 go through an additional PCB.

-rastro

[jgorsk]

It's the SMIQ 02 model

[rastro]

I've included the spectra for an SMIQ06 set to 450MHz and 460Mhz.  I don't know if this will help since it has additional RF paths.
- rastro

[jgorsk]

Thank you very much, that's what I needed to see.

[jgorsk]

I managed to find a few faulty components. The FET at the output from IQCON board and a few amps in the 300MHz
vector modulation signal path were faulty. CW, analog and digital modulations work now but there are still a few errors left.
They are
-313 calibration memory lost; LEV_PRESET
-313 calibration memory lost; VECTOR_MOD
-313 calibration memory lost; LEVEL_ATT

LEV_PRESET calibration fails with 'IQCON no convergence' error message,
VECTOR_MOD and LEVEL_ATT calibrations fail with 'Reference voltage oot (6.9 ... 12V)' message.

In vector modulation mode with no I/Q signals applied the carrier level is about 20dB below the setpoint.
Is the carrier supposed to be suppressed in this mode or should it be as set by the level setpoint?

[analogRF]

I managed to find a few faulty components. The FET at the output from IQCON board and a few amps in the 300MHz
vector modulation signal path were faulty. CW, analog and digital modulations work now but there are still a few errors left.
They are
-313 calibration memory lost; LEV_PRESET
-313 calibration memory lost; VECTOR_MOD
-313 calibration memory lost; LEVEL_ATT

LEV_PRESET calibration fails with 'IQCON no convergence' error message,
VECTOR_MOD and LEVEL_ATT calibrations fail with 'Reference voltage oot (6.9 ... 12V)' message.

In vector modulation mode with no I/Q signals applied the carrier level is about 20dB below the setpoint.
Is the carrier supposed to be suppressed in this mode or should it be as set by the level setpoint?

did you ever managed to fix the 'IQCON no convergence' error?

[zmetzing]

Schematics for the 1084.9800.01 IQ Modulator board, among other things, are located here:

http://eww.ko4bb.com/getsimple/index.php?id=manuals&dir=Rohde_Schwarz

I'm currently diagnosing my SMIQ 03B's failure "ERROR: CW: ALC_ON voltage oot" during CALIB ALC TABLE. The SHF-0189Z final has been replaced, as a shotgun-debugging start. (That was a booger to get out. Hot air @ 375C plus my Metcal on the back tab.) Didn't fix the issue.

Extender cards seem to be unobtanium, so I'll take the advice of others here and pull the front panel so I can have limited access through the front of the machine.

[zmetzing]

Looks like the output is fairly low, so it points to the output stage.

For reference, my 8568A's 20MHz -10dBm reference signal into a Iwatsu 470 MHz analog scope (50 ohm input) shows 200mV p-t-p at 20MHz (correct).



However, the SIMQ's output shows only 100mV p-t-p at 20MHz when set for +10dBm. This is -16dBm.



Handy table here for dBm -> mV (50 ohm) here http://wera.cen.uni-hamburg.de/DBM.shtml

(Yep, I'm a noob at this forum software)

[charlyd]

can this help you: 

[zmetzing]

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".

[smgvbest]

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

[zmetzing]

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. :-)

[zmetzing]

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.

[zmetzing]

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?

[zmetzing]

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

[zmetzing]

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!

[zmetzing]

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.

[zmetzing]

"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 ...

[zmetzing]

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?

[zmetzing]

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?

[zmetzing]

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?

[zmetzing]

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.

[teknut]

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

[zmetzing]

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!)

[little.tesla]

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.

[zmetzing]

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.)

[RecursiveLogic]

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.

[zmetzing]

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. :-)

[techneut]

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.

[Ick]

Late reply to this thread as I spent quite some time reparing a similar  (bult older, SMIQ02 - without the B) unit.

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.

Please mind that the calibration error message (1) "IQCON no convergence" is very different from (2) "maximal level oot" and the detailed asociated debug info "IQMOD fail at frequency.."

(1)The former points at an issue of the IQConverter board: The unit is unable to set/tune or measure the RF level during Level Preset calibration. This points to an error anywhere on the HF path between LO Driver (just before the mixer) and ALC detector near the output of this board. So everything that is bypassed in CW mode (in case CW mode works without errors). Level Preset on the IQConverter is only used in Vector mode (so heterodyne path over mixer is active).
Issue sits with either of the overall ALC control loop (e.g. detector diodes or OpAmps - albeit not very probable if this is the only error, because the same components are also used for CW ALC), PIN diode errors switching the HF path, the Level Preset DAC U5 (DAC08) in combination with N1 OpAmp prducing the bias voltage, the respective current source circuitry V11, V18-V24 +V8/9 current mirror, asociated biasing or the three filters paths (750-1800;1800-2500; 2500-3300) (containing the preset PIN diodes in later board releases). In these filter paths there are MMICs that also can go bad.

(2)The latter - which is described here by zmetzing - points at the IQModulator board: e.g. here with the error on the S2 HF switch, preventing the level preset for CW in the final amplifyer stages of the IQModulator.

@techneut: In case 7 month response time are not too late - focus at the IQConverter board, not at the IQModulator board with this issue.
The IQConverter comes with two main board revisions. The schematics available over the links posted here are for the older revisions, so is the service manual. The principle remained the same and the schematic is also the same in big parts. However some important details like amplifyer stages and filters have changed with the newer revision.

[Antonio Borda]

Good evening,
have you found the firmware to start your smiq, I find myself with the same situation after buying a smiq03b
Boot eorom version 1.26 hx
Cpu board var 8 rev 2
ram 2048k
WIS D 115200.8, e, 1
I restart with winflashpro 1.2.27 with 5.93 it displays error in the middle of the loading it is stopped. I see quit there are other users with the same type of failure, as you have found the solution. Thanks for your help

[drhex]

So am resurrecting a dropped SMIQ03B, after putting in a new screen (still looking for the outer glass/perspex), I have the dreaded 110 Output unleveled. S2 was broken, I replaced that with a HMC270 and now have output, but the ALC still complains. @zmetzing, how did you set debug to get more information? Am I interpreting your posts correctly in that the board has to be closed up to calibrate?
Some photos of the failed switch innards:

[drhex]

OK, replacing the last output FET got it to work again - bit of a bother as R&S decided to solder a little sub assembly across source and drain which needed careful wrangling. Output looking good now, what I can test with my limited resources seems to work fine. Need to find an outer screen now and this is done. Please ping me if you have one kicking about, even if yellowed or such as that would be better than none :-).

[zmetzing]

Congrats! These are great units that can be had for a fraction of what they cost new.

If only I could find a 6 GHz module and a fading simulator module, and then figure out how to convince the software to use them. :-)

[drhex]

Probably same process as getting from 02B to 03B - you just need a factory install key. Can probably be reverse engineered somehow. Do you have info on the 6L variants? SOme around for parts on the Bay...

[Jarek]

Angielski

I also have a problem with SMIQ03
I have IQ Modulator version A240.1084.98.00.06
This is different than the ones described in the posts.
Here are the transistors marked as( .H1 ) .  There are three of them in series under the radiator. The casing is as in the photo.
What kind of transistor is it? Does anyone have a diagram of this version of IQ Modulator?

[drhex]

Schematic I have is for 1084.9800.01S. V102 is in there as SHF-88. Parts list for 1084.9800.01SA shows it as SHF-O186K4230TR made by Stanford

Mine failed after sending it out to calibration. Soldering in another switch didn't resurrect it so bought another modulator and calibrated it myself. Worked reasonably well, +.5dBm off over the whole amplitude and frequency range. Can live with that.

[Jarek]

Thank you Drhex
You're right, it's SHF0186.
My module gets very hot. I am looking for damaged elements.

[drhex]

I have a few more or less broken modulator boards here in case you're interested.

[Qw3rtzuiop]

What kind of transistor is it? Does anyone have a diagram of this version of IQ Modulator?

Take a look here:
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Rohde_Schwarz/Rohde_Schwarz_SMIQ

[Jarek]

Thank you for the offer Drhex.
I've already bought it.
Regards

[Jarek]

ERROR:
   VECTOR_MOD and LEVEL_ATT calibrations fail with 'Reference voltage oot (6.9 ... 12V)

Which reference voltage exactly is it?