New project: R&S SMIQ03B

[nctnico]

I've got the R&S SMIQ03B (300kHz to 3.3GHz RF generator) from MCS Equipment's faulty equipment sale. I got it for a very reasonable price. Listed problems are a broken knob (actually someone modified it) and a low backup battery. I received it today. It works and is loaded with options! It has the OCXO (nope), data generator (not fitted), 2*32Mbit memory extension (part of the data generator), the fast CPU, FM/phase modulator and modulation coder (whatever that may be). No, it has no options. I would like to have FM and phase modulation though. 



It seems to work and going to 300MHz doesn't seem to be a problem. But there are a few obvious problems:
- lots of stickers everywhere
- there is a horizontal line in the display (and discoloring along the edges)
- the RF output is on the rear
- the fan is LOUD!
- the battery is at 2.8V

Swapping the RF out to the front is easy except for the fact that the bracket to hold the N connector is bend:


The first order of business will be getting a new battery and a new fan (the old one is worn). My HP RF generator magically died the day I ordered the SMIQ03 and I really need an RF generator for some testing.

I think I feel another TFT conversion coming up.

[maginnovision]

How loud is the fan? I just finished rebuilding the fan in my NGPV supply. Went from not working, to LOUD, now it is all good. Hope your fan is more standard, not some 250vac monster motor.

[DaJMasta]

Had an 06 that I repaired a while ago, the main fan was sort of loud so I replaced it with a 120mm Scythe Slipstream with a tad more CFM and it worked great.  The power supply fine in mine was very quiet, way under even the quieter main fan.

[nctnico]

Hmmm I'm starting to get the feeling my unit has been gutted. The OCXO isn't there! I've found a picture on Ebay and the connectors to which it should be connected are empty.
Edit: just checked: none of the option modules listed on the back are fitted.

[sorenkir]

"ERROR" on the main screen: I hope it is the backup battery!
Michel.

[nctnico]

"ERROR" on the main screen: I hope it is the backup battery!
Michel.

The only error in the log says that it needs to run the self calibration routine to restore the self calibration values. The tag says that the unit displayed an error 313 saying the cal memory is lost. According to my research this should be a matter of replacing the battery (which is on its way).

[Qw3rtzuiop]

I wanted to buy that thing but changed to the broken SMU200A.

BTW
The service manuals for the SMIQ are avaiable here:
http://eww.ko4bb.com/getsimple/index.php?id=manuals&dir=Rohde_Schwarz

[nctnico]

@Qw3rtzuiop: I've looked at the SMU200A but considered it overkill (and probably too expensive).

Meanwhile I made some progress. With a new battery and a self calibration the SMIQ03B seems to work. I did some checks to see if the output levels work and the frequency range is OK. I also found the status menu: mine has been on for over 6 years with over 20 million cycles on some of the attenuator relays 

I replaced the main fan but it is still quite loud. I'm going to try the fan Dajmasta suggested. I also found out that the small fan over the CPU is totally worn as well (it is bloody noisy) so I ordered a replacement for that as well.

I have not decided on a TFT conversion yet and I'll post some pictures later.

[eb4eqa]

Hi!

I see you have a broken brightness knob. I savaged two trimpots and they fitted perfectly:



You are missing the feet too… I printed feet for the SMIQ I had:








...and also the missing power button:



I must have the .STLs somewhere, if you want them just let me know.

Roberto EB4EQA
www.rbarrios.com

[nctnico]

Meanwhile I managed to make some progress.
I got a new PAPST 4312/12 fan but even with a 33 Ohm resistor in series it made a lot of noise and the airflow wasn't that good. I decided to go with Dajmasta's suggestion and bought the 120mm Scythe Slipstream (1600 RPM version). Meanwhile I also noticed there was more noise coming from somewhere else... it turned out the be the CPU fan which was completely worn.

Who in their right mind uses rivets on a fan? Turn a standard part into a special part 

The fan is again a standard PAPST part so getting a replacement was easy. This time I used screws to fix the fan to the bracket:


I did contemplate to put a stick-on heatsink on the CPU but decided against it because there might be other parts in the front panel which need cooling. Interestingly the centre of the fan is aligned with the centre of the CPU.

While I had the front panel apart I made use of the opportunity to capture the LCD screen signals with a logic analyser:


For now I have put my SMIQ03B back together. The TFT conversion will have to wait until I have finished some other projects.