R&S SM300 Power Reads 13 dBM High - Attenuator Problem? - Page 1
Forum section: electronics / repair

author: NY2KW
author_rank: Regular Contributor
timestamp: November 08, 2019, 03:14:30 am
content: I picked up a R&S SM300 signal generator that’s worked perfectly except the RF output would disaapear higher than -25dBM. It was smooth from -100dBm to -25dBm but 1 dBm higher and the signal would disappear - there was no signal from -25 dBm up to +13 dBm (the specified limit). This was same across the frequency spectrum I could measure 1MHz – 1.5 GHz. A second problem was for signals set in the range of -100 to -25dBm, the power settings on the SM300 always read about 12-13 dBb higher than true output as measured on my Rigol spectrum analyzer (confirmed with my HP 438A power meter). The service manual was useless and my call to R&S said they could only offer an RF module replacement for $2600.I scoured the web for tips and surprisingly found none but I noted that once in a while a SM300 would come up for sale with a note that power would not exceed -25 dBM. I finally found one reference – a single sentence that someone fixed this problem by replacing a gain block AGB3303 (picture attached and AGB3303 circled). I tore down my SM300 and replaced the AGB3303 on the RF Gen board and I now have full level control on any frequency from -100 dBM up to 13 dBM !!! However the SM300 still reads 12-13 dBM higher than actual output, so if I set if for 13dBM, I read an output of 0 dBM.Now this is still a huge improvement but I would like to see if it can be fixed further. I found one other reference that the SM300 has 4 HMC307 step digital attenuators 0 -31dBm (see 2nd picture) and that one of these or the control line may be bad. These attenuation steps require a (-)5v control line otherwise they are low and not switched in. There are no SM300 schematics – is it more likely that a control line is stuck at (-)5v or that one of the HMC307 need to be replaced. I cannnot test this board in circuit as it has a proprietary backplane. I thought to test the board on the workbench but these smd pins are tiny to postion test probes. Should do a blind shotgun replacement of the 4 HMC307?MOD: Images removed at request of owner.

author: COSMOS2K
author_rank: Contributor
timestamp: November 15, 2019, 06:20:51 pm
content: Hi Jerry:I see that you have taken advantage of my work to publish the information that I have created.It is not a good action on your part, I think it is a lack of respect and education on your part, be honest with the forum and publish the origin of the photos, do not attribute the work of others.Regards.

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 15, 2019, 06:29:34 pm
content: Are you seriously trying to claim copyright on images of a PCB? Christ, dude.

author: EEVblog
author_rank: Unknown
timestamp: November 15, 2019, 11:49:57 pm
content: If NY2KW marked up the photos then it's a "transformative work" for educational purposes, so Fair Use applies.But yes, nice to acknowledge the source.

author: NY2KW
author_rank: Regular Contributor
timestamp: November 16, 2019, 02:47:43 pm
content: Hi Manuel,I did not intentionally post your picture of the SM300 Gen board. I cannot see the image any more but I thought I had posted a picture of the board I had taken with my phone camera. In fact if you look at my other earlier EEVBlog post it shows a picture that I made of the board (copy of which I am posting with this msg)https://www.eevblog.com/forum/testgear/how-to-test-a-rf-gen-board-out-of-circuit/msg2775714/#msg2775714If I posted your picture it was by mistake because I kept all the images (yours and mine) in the same PC file folder. Sloppy on my part and I apologize but nothing sinister was intended, I assure you.I wanted to post my success at replacing the gain amp --- which by the way was something you had not suggested but was from an obscure anonymous post on an Agilent related site.Also I make no attempt to conceal my identity and that is why I proudly use my amateur radio license call sign .Best wishesJerry NY2KW

author: COSMOS2K
author_rank: Contributor
timestamp: November 16, 2019, 11:10:33 pm
content: Hi Jerry NY2KW:Apologies accepted.I usually look at these things a lot, because the work that some professionals do is fraudulently used on the internet, logically those of us who work in these jobs do not like these things to happen, since we live from it.I always respect the intellectual property of people, of forums and of everything found on the internet, in the same way that my properties are respected as well.I have never said that you hide of course I have always believed that you are a gentleman in that sense.Topic change:Regarding the SM300 I am waiting for the parts to arrive to repair, I have made diagrams, I studied the RF PCB getting to remove five shields to see how it is conceived.As soon as the generator is repaired, I will try to repair another equal from a customer with the same problem.I have also made a list of SMD components with codes to facilitate repair.Give me time to repair the equipment and prepare a tutorial about it because in the NETWORK and through R&S not much is achieved.Without acrimonyRegards

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: November 20, 2019, 08:33:40 pm
content: Were are COSMOS2K images now? Is the result: no one can benefit from them now? Do you have a site/blog for this device?

author: COSMOS2K
author_rank: Contributor
timestamp: November 23, 2019, 02:39:39 am
content: Hi:I don't understand your message well sorry.If there are images, I have many of this repair, take many photos to help NY2KW, but I have never liked to be published without the permission of the creator, because in addition to being their property is also responsible for the content of them.On the other hand the subject in question is already clarified.As I said there are many photos and also synoptic schemes that I have created and will be published when the parts arrive for repair, I will create a thread for this purpose with the experiences with this signal generator..Also forgive my English is not very good, and I hope we understand each other correctly.Regards.

author: COSMOS2K
author_rank: Contributor
timestamp: November 23, 2019, 03:02:01 am
content: Quote from: YetAnotherTechie on November 20, 2019, 08:33:40 pmHi:I forgot to comment. Do you need those images? Do you have this faulty signal generator? Do you need help about it?I have to say that in your profile you don't see what country you live in and I'm curious to know.Regards.

author: EEVblog
author_rank: Unknown
timestamp: November 24, 2019, 08:34:58 am
content: Quote from: YetAnotherTechie on November 20, 2019, 08:33:40 pmCOMOS2K asked for them to be taken down as they are his images, and threatened to put a copyright claim on my server if I didn't. I just didn't need the grief fighting over a few stupid images.

author: EEVblog
author_rank: Unknown
timestamp: November 24, 2019, 08:38:06 am
content: Quote from: NY2KW on November 16, 2019, 02:47:43 pmSorry, I thought all the images belonged to COSMOS2KFeel free to repost your own images here.

author: COSMOS2K
author_rank: Contributor
timestamp: November 24, 2019, 03:09:13 pm
content: Quote from: EEVblog on November 24, 2019, 08:34:58 amHi:Sorry, I did not "threaten" just asked that my images be removed in their own right, but you took away what you wanted, without asking what they were. If I had made a claim it would be in my full right, but I have chosen to notify the moderation, what have I done wrong?On the other hand I have to say that a forum with the "apparent" seriousness that is expected has disappointed me, because in some way it is more worthy of the one who copies / paste and usurps than the creator of such information.Sincerely as you have pointed out are some "stupid" images, but they are just at the qualifying height of the forum.I really expected more respect and education but I see that there are many usurpers of information who also think only of their own damage and not the intellectual property of their forum partners.Greetings and see you soon.

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: November 24, 2019, 03:35:48 pm
content: Quote from: COSMOS2K on November 23, 2019, 03:02:01 amHello,I asked where they are because NY2KW must have taken them from somewhere? In which case you could have asked him (NY2KW) to remove them and point to your site, that way you still have full attribution and others can benefit from them, as it is, there's not much information on the web about this device. If he didn't remove them, then you complain to a moderator.I don't own or need to repair this particular SG, i just like to see how RF equipment is made, what parts they use and how they fail, because besides interesting it might help me one day to fix my own equipment, and i was following this topic because i found those images interesting, that's all.I live in Europe, not in Spain.

author: EEVblog
author_rank: Unknown
timestamp: November 25, 2019, 12:29:12 am
content: Quote from: COSMOS2K on November 24, 2019, 03:09:13 pmYes, you did threaten legal action, I quote:"If this image is maintained publicly in the forum, I will have to make use of the data protection law."QuoteLegally, nothing, but it's a very bad look to police technical content like this on a public technical forum. You won't win friends here by being this anal retentive about an image of a PCB.QuoteYou are welcome to leave any time you like.QuoteChill out dude, seriously. Someone just shared your photo, virtually everyone else here would be happy that their content is being shared. You took it to the extreme.

author: wilfred
author_rank: Super Contributor
timestamp: November 25, 2019, 12:58:45 am
content: <quote>Legally, nothing, but it's a very bad look to police technical content like this on a public technical forum. You won't win friends here by being this anal retentive about an image of a PCB.You are welcome to leave any time you like.Chill out dude, seriously. Someone just shared your photo, virtually everyone else here would be happy that their content is being shared. You took it to the extreme.<end-quote>So someone politely asserts their right to attribution of their work and they get to this. WOW. Being called anal retentive and invited to leave. Now that is taking it to the extreme.

author: EEVblog
author_rank: Unknown
timestamp: November 25, 2019, 01:54:10 am
content: Quote from: wilfred on November 25, 2019, 12:58:45 amWrong. He didn't want attribution, he wanted it removed and threatened legal action if I didn't.QuoteI extend the invite to you as well Wilfred, you're welcome.

author: COSMOS2K
author_rank: Contributor
timestamp: November 26, 2019, 08:22:01 pm
content: Hi:I have really been amazed to be the victim judge me and invite me to leave? Really awesome. I have only requested that my rights be exercised, but I have realized that in this forum you do not look at those things, you look more at usurping.I must also say that as administrator you leave enough to be desired and is a total ignorant of the law, because he has published a literal part of my PRIVATE message to moderation, and that is not legal, sincerely every time he writes he puts the paw for not understanding or for not asking, but don't be disturbed, keep it that way.I have really been amazed by the reaction of some people in this thread, because in principle (if someone has not read it) I politely asked the one who published my work without getting a response or reaction, so I sent a PRIVATE message to the moderation / administration, resulting in all this mess.Really sometimes we are blinded by information that is not found on the internet and logically we want to have it without thinking who puts it in these media and without thanking the work, I think it is not a good practice. On the SM300 I have some schemes, technical information created by me and reverse engineering of some plates not only of this model and brand, but also of others of which there is no information, in principle my intention was to post them in this forum, but seeing the deal and the ways of the administration that thinks with the anus, I will not post them.I honestly believe that I have not deserved this, I have been discriminated against, and I think it is not logical, I get the impression that you are a bit xenophobic in this regard and have shown it, especially not knowing how to administer a forum for ignoring the law, and take the victim as accused, so I make a copy of this public page to prove the wrong ways of the administrator.Finally tell you that in this forum (as in many others) the law is broken in many things, take a little time to look at it and you will see it, because these things usually end up with good forums like this.Mr. Administrator, study books of humility, respect and education, you may sleep better after reading.Remember that my English is not very good if something does not understand ask before answering wrongly.Regards.

author: DaJMasta
author_rank: Super Contributor
timestamp: November 26, 2019, 10:05:37 pm
content: If you asked an administrator or moderator of the forum to remove the images because they were your intellectual property before trying to actually talk to the person posting them, you've started the conversation in a hostile stance. While your first couple of posts do not threaten legal action, you are accusing the original poster of willful content theft and insulting them personally. The removal of the photos following your inquiry to the moderators happened before your second post with a more conciliatory tone.Not only did you insinuate legal action against the poster, but the posts from the personal message indicate that you threatened legal action against the forum owner as well for a user publishing a photo you took - even if that's technically possible under the law (and the laws where this forum is operated from may be different), that suggests you have no interest in solving the problem amicably and you are directly threatening the livelihood of the forum operator. This is the equivalent of threatening a chargeback on a credit card or a DMCA on youtube or similar - which is abuse of the systems in place and is a bridge-burning cut-and-run sort of tactic for interaction. You cannot realistically expect a friendly, courteous reply or future dealings if you make such a legal threat, regardless of whether it's a valid legal claim or not (and since the pictures were edited to point out specific parts, I'd agree it probably falls under fair use and wouldn't hold up in a court of law.)Your threatening legal action against the forum for a user's post of a picture you took is about the equivalent as if Rohde & Schwarz threatened legal action against the forum for you sharing a picture of their PCB on a public technical forum. What light would you view them with if they made such a claim? It would be a PR nightmare if it was done by a company (and this kind of thing has happened in other sectors, at least).Your claims of xenophobia and discrimination seem completely nonsensical from my perspective, I think you just didn't like getting called out for the claims you made that effectively forced the moderation team to move the images from the first post. Your English is plenty good enough to be understood clearly, you're just dramatically overreacting to what sounds like a mistake from the OP that could have been resolved by requesting through private messages that he take them down.I hope all this stuff hasn't stopped the OP's repair, at least.

author: EEVblog
author_rank: Unknown
timestamp: November 27, 2019, 09:52:46 am
content: Quote from: DaJMasta on November 26, 2019, 10:05:37 pmThat reminded me of the time a VP at Lecroy contacted me and demanded I remove this entire thread about hacking information one one of their products:https://www.eevblog.com/forum/testgear/lecroy-options-recovery/Guess my response

author: EEVblog
author_rank: Unknown
timestamp: November 27, 2019, 12:14:39 pm
content: Quote from: COSMOS2K on November 26, 2019, 08:22:01 pmLet me educate YOU on the etiquette of how technical forums work, and how you should act in descending order in a situation like this in order not to piss anyone off:1) Chill out and do nothing, it's just a photo of a PCB, it's not like the guy copied your life's work. Assume zero ill-intent. People are here to share technical info freely.2) Maybe ask politely for some attribution, either privately or publicly.3) If you still aren't happy and REALLY want your precious PCB photo removed, ask the poster politely via private message to remove it.4) If you still aren't happy ask the forum moderators politely to consider removing the image, no need to mention copyright and the law and be all confrontational.5) Threaten legal action against the forum owner as a last resort.You took the nuclear option and jumped right to #5, for what, a bloody photo of a PCB!Try not to do a duche thing like that in the future. I'm cutting you a huge amount of slack here by ignoring the legal threats and xenophobia slander, don't push it.You're welcome.