Help me identify unknown components from R&S SMP03 - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: October 09, 2024, 12:20:32 am
content: Hi,I am trying to repair a R&S SMP03 Signal Generator. I have had this unit for few years now collecting dust. Since i had the unit it had this YPLL cal failed error and warning FM Coil over driven message.The output frequency drifted more than a GHZ all across. I tested the yig coil externally in the past, both coarse and fm coil seemed to work. However based on multiple account people posted on the internet stating its always the YIG, I placed the unit in cold storage.Two days back i manage to get myself another SMP02, which shares the similar yig and yig control module, but this unit output level is bad. Swapping the yig and the control module vice versa revealed, the SMP03 yig and the controller is good, it turns out the yig sampler module is the culprit. I am now trying to identify and confirm few suspected component. Please help me out here.This is the moduleThe marking is ( 3866 and 5160)MMIC amplifier with marking 420 ( this is good, for sure, but just want to know what sort of gain it produce)The 3866 i believe is MRF3866 (please help me to confirm)https://www.microsemi.com/sites/default/files/datasheets/CDROMmini/MSC1312.pdfThe 5160 I believe is MRF5160 (please help me to confirm)https://www.datasheets360.com/pdf/3065652880796577876The pin out seems to match.The amplifier i guess its from minicircuit, but i cant find a "140" marked unit yet from mini-circuit.Help and opinion is much appreciated.If all things works well, I will have a 27GHZ signal generator

author: fzabkar
author_rank: Super Contributor
timestamp: October 09, 2024, 02:20:56 am
content: "420" could be Avago AT-42085 or AT-42086.https://www.eevblog.com/forum/repair/rf-si-transistor-identification/msg5634619/#msg5634619MRF3866 on page 654:https://mirrorservice.org/sites/www.bitsavers.org/components/motorola/_dataBooks/1994_Motorola_RF_Device_Data.pdfMRF3866 and MRF5160 are complementary pairs.

author: CrazyTiger
author_rank: Regular Contributor
timestamp: October 09, 2024, 02:45:08 am
content: Wow,Love the MRF Device databook.Thanks,

author: Harry_22
author_rank: Frequent Contributor
timestamp: October 09, 2024, 08:38:09 am
content: Congratulations, you have diagnosed the fault with absolute certainty. This is one of MRF transistors. They are mostly loaded here.@ fzabkar, I am following your identifications with interest. This time as always you are right. This is AT-42085PSNTE2511 and NTE2512 just have been ordered for my SMP. Hopefully they will work here.https://www.tme.eu/Document/5321375d488a24e92c8cfb7f10d897a0/nte2511.pdf

author: CrazyTiger
author_rank: Regular Contributor
timestamp: October 10, 2024, 02:02:18 pm
content: Quote from: Harry_22 on October 09, 2024, 08:38:09 amHi, my SMP03 is fully working now. I exchanged the MRF3866 with a random high frequency n channel transistor, and MAR-8 was also replaced. Everything runs perfectly now, YFOM cal passed, frequency is locking perfectly. My output level tested around +/- 0.2 all across.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 08, 2024, 10:08:16 am
content: I am still waiting for transistors...Seems I have bought the last ones in the world.