R&S SMIQ SSW124 -> HMC270 replacement ("ALC failed" error) - Page 1
Forum section: electronics / repair

author: OH2LIY
author_rank: Contributor
timestamp: January 04, 2018, 06:07:34 pm
content: Hi, here is couple pictures how I did replace burned SSW124 SPDT switch to newer HMC270 switch. "ALC failed" error seems to be quite famous error on old SMIQ and finally my SMIQ did same thing. It didn't take long to find that last SSW124 before output stage was bad (signal from down mixed side was gone). Bigger problem was to find new one. After studying what can be found from Evilbay, I did order HMC270.Flipping HMC270 over, RF pins match nicely to original layout, and it's much easier to solder to PCB using little copper strip (don't try this without microscope). Probably original switching voltage levels are little too high for SSW124? but HMC270 can't handle them at all. Control voltages can be lowered easily, just adding paraller resistors to R1150 and R1151. Using 1,8k did give -4,22 V and 2,2k -4,68 V. Using 2,2k/-4,68 V gives over 80 dB attenuation measured from RF output.OH2LIY

author: Aleksandar
author_rank: Contributor
timestamp: January 05, 2018, 07:14:46 am
content: A very useful experience for all of us who have the SMIQ.Thank youAleksandar

author: wldshy
author_rank: Contributor
timestamp: March 03, 2018, 06:19:16 pm
content: I almost done the same job, but I used a converter board instead of flip-chip. I set the control voltage to -5.6V, for the voltage show on the datasheet is -5~-7V by attach a 6.2k resistor vertically to the capacitor.Now, unexpected harmonics have disappeared.But error 183 and error 180 still exist.It looks like you have schematics of SMIQ, can you share it with me? or can you help me look at the position of TP2122 on the board. I have an Unsuitable TP2122 value(0.991V for me, and -4~-0.5 on service manual).

author: OH2LIY
author_rank: Contributor
timestamp: March 09, 2018, 06:46:11 pm
content: Quote from: wldshy on March 03, 2018, 06:19:16 pmHi, I just scanned IQ modulator card schematics (output stage card). Hopely these helps you.https://www.dropbox.com/s/q5xddnpzbgtijrv/SMIQ_IQ_Modulator_schematics.pdf?dl=0Ramppa

author: hscade
author_rank: Contributor
timestamp: March 09, 2018, 07:30:42 pm
content: Quote from: OH2LIY on March 09, 2018, 06:46:11 pmI'm currently try to fix also the ALC Error on my SMIQ and now thanks to you I've schematics.If you've schematics for the IQCON Module please upload them

author: analogRF
author_rank: Super Contributor
timestamp: February 19, 2019, 01:43:22 am
content: Quote from: OH2LIY on March 09, 2018, 06:46:11 pmCould you please do the same excellent scan job with the IQ Converter board (1084.9300.xx)?My SMIQ06 cannot do the Level Preset calibration and stops with "IQCON convergence failed" error. It cannot also do IQ modulation.The schematics would be highly appreciated.

author: OH2LIY
author_rank: Contributor
timestamp: March 08, 2019, 07:03:04 pm
content: Hi, scanned schematics for IQ-Converter is just uploaded to KO4BB...Ramppa

author: analogRF
author_rank: Super Contributor
timestamp: March 08, 2019, 08:23:05 pm
content: Quote from: OH2LIY on March 08, 2019, 07:03:04 pmThanks!Maybe it takes some time before it appears on their list. It has not showed up yetEDIT: you can find it on ko4bb if you do ftp. It will show up for regular download later on.Thanks again Ramppa

author: Seint
author_rank: Newbie
timestamp: February 04, 2024, 03:24:01 pm
content: Quote from: wldshy on March 03, 2018, 06:19:16 pmHi,Could you finally fix the ERROR 180? I have this problem on my SMIQ03. Any tips will be highly appreciated.

author: KeBeNe
author_rank: Regular Contributor
timestamp: February 05, 2024, 03:18:39 am
content: Hello,Error 180/183 is reported if a calibration was not successful, the reason for this is displayed at the point of termination.You can also activate password level 2, then you can switch on a debug mode, play with it to learn the operation.

author: Seint
author_rank: Newbie
timestamp: February 05, 2024, 11:14:30 pm
content: Quote from: KeBeNe on February 05, 2024, 03:18:39 amThank you for the tips, just went through the test point according to the service manual and found some abnormalities. Please see attached. Don't really know where to start ...By the way, what is the password for level 2 and 3. I already got to know for the level 1.