Philips PM3340 2Ghz Digital Scope: Good/Bad? - Page 1
Forum section: electronics / testgear

author: SaabFAN
author_rank: Frequent Contributor
timestamp: January 05, 2016, 07:27:53 pm
content: HelloI just came across a Philips PM3340 2Ghz Scope on ebay LINK:http://www.ebay.de/itm/FlukePhilips-PM3340-2GHz-Digitalspeicher-Oszilloscope-mit-FFT-usw-/272096155168It apparently is in working condition and because I personally like Philips instruments and at least one of my projects has already taken me beyond the capabilities of my PM3320A, this one is rather appealing to me, but the question is: Are these scopes good/usable and what would be a good price? The PM3320-Models regularly are sold for about 200€ on ebay (+/- 30€). So I guess that this one will be in the area of 250 to 300.

author: tautech
author_rank: Super Contributor
timestamp: January 05, 2016, 07:35:23 pm
content: Old thread FYI:https://www.eevblog.com/forum/buysellwanted/philips-3340-2ghz-scope-(uk)/

author: TurboTom
author_rank: Super Contributor
timestamp: January 05, 2016, 08:31:18 pm
content: This is really a special RF instrument - sequential sampling only (means it can only display periodical signals) and 20µs/div slowest horizontal deflection, so it's no use for audio and similarly "slow" signals whatsoever. Don't buy it if you're looking for a general purpose o'scope...Cheers,Thomas

author: Emo
author_rank: Regular Contributor
timestamp: January 05, 2016, 08:36:51 pm
content: Hi,I have one and it is indeed best suited for RF. Only 50ohm input and low sampling rate. It is however a beautiful instrument for debugging transmission lines. It is heavy and fully documented.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 05, 2016, 09:54:12 pm
content: How old is that?? Late 1980s?

author: SaabFAN
author_rank: Frequent Contributor
timestamp: January 05, 2016, 10:01:57 pm
content: Yes, I think so.I have a PM3320A here, which I actually use more than my Rigol DS1054Z because it's somehow more intuitive to use^^According to the datecodes, most chips in it are from 85 to 88, with at least a few made in 1990 and also some made all the way back in the late 70s (programmable Timer from Intel).So far, these scopes seem to be of pretty solid construction. I sold another PM3320A a while back with a defect I couldn't fix and the buyer told me that he got it running again after some additional tinkering.I don't know if this also applies to the PM3340, which is probably using quite different components to achieve the higher bandwidth.

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 05, 2016, 11:25:09 pm
content: Can't this scope be used as a general purpose oscilloscope in the lower bandwidth range?Does it provide sampling memory? How many seconds can be sampled at given bandwidth?How is the FFT functionality?Can it act as a basic spectrum analyzer up to 2 GHz?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 06, 2016, 06:38:39 am
content: Quote from: Hydrawerk on January 05, 2016, 09:54:12 pmWe got several Philips/Fluke PM3320, PM3323 and PM3340 scopes back in 1988/1989 shortly after they had been introduced.I liked them a lot, they were easy to operate, reacted quickly to user input (and offered a numerical keypad!), and proved to be extremely reliable. PM3320 and PM3323 quickly became my day to day scopes back then. At least until the faster HP 545xx Series came outQuote from: pascal_sweden on January 05, 2016, 11:25:09 pmTo some very limited extend only, and even then it's a very poor general purpose scope because of its timebase limitation, the 50ohms only inputs, and because it's no real-time scope. As others already stated it's a sampling scope made for RF analysis (primarily eye diagrams), something which back then was not possible to do with real-time scopes because their sample rate was too limited.These days the scope and its technology have long been obsolete. 2GHz real-time scopes have been available since the end of the '90s.QuoteThe PM3340 (as the PM3320 and PM3323) has four separate sample memories of 4kpts each which means you can store four different waveforms.As a bonus, the PM3320/PM3323/PM3340 are 10bit scopes.QuoteVery slow, and really very basic. FFT was an option on PM3320 and PM3323 (if I remember right it came standard on the PM3340), and if my memory serves me right it used some 500 points or so. Back then that was great. 27 years later it simply isn't.QuoteNot really. FFT in those scopes was meant to look at the frequency components of a repetitive signal, and the (by today's standards) painfully slow processor and the low memory present severe limitations to its performance.

author: Emo
author_rank: Regular Contributor
timestamp: January 06, 2016, 09:05:57 am
content: To give an impression how the sampling is implemented, just a part of the input circuit. (unfortunately hardcopy A3, difficult to scan the full page) and the detailed characteristics from the service manual.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: January 06, 2016, 11:07:53 pm
content: Interesting... Do I understand this correctly: The Scope is sampling/Down-Converting the Waveform in the analog domain before it is sent to the hybrid (P2CCD-Chips quickly store the Sample-Points and then the 50kS/s ADC digitizes these Samples) acquisition-system? That's quite a long way for the Signal from the inputs to the screenI also read that the PM3323 used at least on some boards SMD Electrolytic Capacitors, which are prone to leaking/drying up because of all the heat that is generated by the 500MS/s acquision-System. Is this also the case in the PM3340?

author: dom0
author_rank: Super Contributor
timestamp: January 06, 2016, 11:28:15 pm
content: In a way, yes. It's basically the same tech analog sampling scopes used since the 1950s or so, just that instead of projecting the dot-pulse-train onto a XYZ display device an ADC digitizes them.

author: Emo
author_rank: Regular Contributor
timestamp: January 07, 2016, 08:52:10 am
content: OK,As it was a long time ago that I had a peep insight, I opened it up and made some pictures. Luckily I did so, because I found two boards that were not seated correctly.An overview after opening the top(mostly digital processing) and bottom(analog parts)Clearly visible are the delay lines constructed out of coaxial linesThe card cage is well organized and it is easy to find their function(third image)

author: Emo
author_rank: Regular Contributor
timestamp: January 07, 2016, 09:00:54 am
content: Most of the digital boards consist of through hole componentsImages;A11 ADC boardA9 DPU boardA8 DPU controlA7 IEEEA6 micro processor boardA5 Logic management

author: Emo
author_rank: Regular Contributor
timestamp: January 07, 2016, 09:07:28 am
content: Images;A4 Display memoryA3 Display controlA2 Display DACand the display board(forgot the final amplifier)The power supply is huge and is completely discrete

author: Emo
author_rank: Regular Contributor
timestamp: January 07, 2016, 09:18:22 am
content: The analog part is most interesting(bottom of the instrumentThe input section is well shielded and the delay line takes quit some spaceAfter opening up the trigger front end amplifier more RF parts show up and this unit is perhaps the most complex partThe trigger processing is complex. I expect due to some special functions(transmission debugging)The main signal is straight forward and built with through hole components.The only shielded box I didn't dare to open up(seems almost glued) is the actual sampling unitFinally just some RF signal to show the screen in action(needs some vertical alignment, still on my to do list)One of the very nice features on this scope is the green auto button.My use is mostly the investigation of SDI signals

author: nctnico
author_rank: Super Contributor
timestamp: January 07, 2016, 09:48:02 am
content: I think I see a capacitor leaking on that HF board. I'd look into that!

author: Emo
author_rank: Regular Contributor
timestamp: January 07, 2016, 12:16:33 pm
content: Tnx!, yes it does look suspicious. that unit was anyhow very dirty with all stuff coming from beneath as well due to missing feet.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: January 08, 2016, 01:07:57 am
content: That golden RF-Board loooks magicalThere seems to be quite a bit more SMD-Stuff in that device than in the PM3320A, where SMD-Components can only be found on a few daughter-boards and there are no electrolytic capacitors on those.Both that and the fact that it is basically only usable for RF takes it out of my area of interest. Although it would be interesting to look at the waveform of the VCO I'm trying to build in my Spectrum-Analyzer project^^What I find interesting is the fact that the Firmware on the processor-board seems to be interchangeable between the three scopes from this series (PM3320A, PM3323 and PM3340). Do you have any means of reading these ROMs and uploading the Firmware somewhere?Btw. does calculating an FFT also take about 15 to 20 seconds on your unit as well? Once I activate certain math-functions, like FFT or Max/Min-Mode, the scope gets pretty sluggish.

author: Emo
author_rank: Regular Contributor
timestamp: January 08, 2016, 02:36:04 pm
content: Hi Saabfan,I uploaded the firmware of the EPROMs to KO4BB. The four EPROMs are Intel 27c010 200V DIP package (128k xand yes, the FFT takes some time ~10 sec on average however no sluggish experience on my side.Currently recapping some boards. Like nctnico noticed on the RF trigger input board, all 10uF SMD caps need replacing(other values and caps appear within specs after checking them with DE5000)

author: nctnico
author_rank: Super Contributor
timestamp: January 08, 2016, 03:19:58 pm
content: Make sure to wash the boards. Ethanol and StMarc (paint cleaner on the Dutch market which is similar to simple-green cleaner) are good solutions for getting rid of electrolyte.

author: dom0
author_rank: Super Contributor
timestamp: January 08, 2016, 03:33:14 pm
content: Holy paint cleaner?

author: nctnico
author_rank: Super Contributor
timestamp: January 08, 2016, 03:36:49 pm
content: Yes, and angel approved!

author: wazoo
author_rank: Contributor
timestamp: November 02, 2016, 01:15:09 pm
content: Hi thereDoes anyone knows how to repair this oscope ??I have received one PM3323 and first impression is that it has "big noise" on both channels.I powered ON and then set channel A and B as GND input (no DC, no AC)Normally I get a plane line , but in this scope it shows full scale noise.I have read that is a tipical issue, but can not find who explain what capacitor needs to be changed.Does anyone knows about ??Thank to allApologize for my english

author: Emo
author_rank: Regular Contributor
timestamp: November 02, 2016, 03:01:30 pm
content: Hi Wazoo,Is it possible for you to include a picture of the screen with the noise? Have you tried to display a known source by using the green "auto" button?Because of the modular way these scopes were built, the source might be isolated by disconnecting the path between modules. Do you have any documentation of this scope?Eric

author: SaabFAN
author_rank: Frequent Contributor
timestamp: November 02, 2016, 04:22:57 pm
content: Hi Wazoo,Is the scope you have by any Chance from eBay in Germany? I saw one there last week and i noticed that the seller had turned down the intensity for the Traces but there was still some of the noise visible in the pictures.Repairing the noise-problem is pretty straigt forward: Replace ALL electrolytic capacitors. Especially the SMD-Types will have dried out by now, which introduces all kinds of noise into the supply-lines.There could be other problems with the unit, but the noise-problem is a known issue with the entire PM3323 series. Just make sure you don't damage the pads when replacing the SMD-Caps.Gesendet von meinem Nexus 4 mit Tapatalk

author: wazoo
author_rank: Contributor
timestamp: November 02, 2016, 06:19:19 pm
content: - EmoI add 2 pictures to show what I see.The 2nd shows a 50ohm patch from CAL to channel B (I take photo after change fron CH A)The 1st is after bootup and pressed green AUTOI found user manual and service manual, but I have not read it yet.I have published a short video on youtube "Philips PM3323 noise input"thats it what I can see.--------------------------------------------- SaabFANNo, it is not from Ebay. It is an opportunity from my workplace.They will put some "old" electronic devices on trash, because of "out of calibration".They are kept stored for many years.probably it is damaged because of age.I have good skill on SMD desolderingwhen you say "ALL"..... it means that I need to be patience and replace "ALL" of them ??hard work but not impossibleThanksOk. then I need time to do that.... step by step

author: SaabFAN
author_rank: Frequent Contributor
timestamp: November 02, 2016, 11:30:31 pm
content: Unfortunately, it means almost every one of the blue axial caps and all of the SMD ones. Only the bigger ones seem to be immune to the disease that these scopes fall victim to.Luckily the caps only seem to dry out and not leak all over the board (probably because the cans are mounted upside down on the big mainboard in the bottom of the scope) and destroy traces and whatnot.Another good thing is that it seems that replacing the caps is enough to make the scope work again. No major readjustments or anything that would require expensive test-equpment (although I managed to get my PM3320A calibrated with quick and dirty hacked together stuff like a 74AC14-Based Time Domain Reflectometer with a simple 14dB attenuator attached to it, an ebay signal generator and my DS1054Z as the "calibration-standard").The bad thing about this is the type of capacitor used: Axial through hole capacitors made by Philips. Replacements cost about 40cents per piece in 25 quantity packs on Digikey, so I'm guessing that it'll take about 50€ and an entire weekend of soldering to get the scope running again.The PM3320A seems to have no real problem in this regard, although adding some capacitors to the +15 and -15 Rails on the ADC-Board reduced the noise-level to that of my DS1054Z. But it also only operates at half the samplerate and is rated for 200MHz instead of 300.

author: wazoo
author_rank: Contributor
timestamp: November 03, 2016, 10:34:56 am
content: thanks SaabFANI did not open yet.I saw pictures posted by Emo and can imagine how is it insidehave both Rigol 815 SA/TG and 1054Z osc, with a signal generator. ( "low cost" basic tools for repair)I found service manual too, that include check/calibration processnot read yet .... 700 pages !!!But now I need some time to fix this scope.good news if only capacitors replacement needed.suppose that some of them needs to be 105C , right ??when I open it i'll check them and write a BOMI will try to post some pictures during process....

author: David Hess
author_rank: Super Contributor
timestamp: November 03, 2016, 06:55:36 pm
content: Quote from: Wuerstchenhund on January 06, 2016, 06:38:39 amMost of those real time DSOs supported equivalent time sampling so while they had a high enough sample rate, their limited bandwidth was the larger problem.QuoteThey are not obsolete if you want instantaneous non-destructive overload recovery and predictable frequency and transient response.Sampling oscilloscopes are still useful for metrology like calibrating a reference level pulse generator used to calibrate a modern high bandwidth real time oscilloscope. A modern 12 GHz sampling oscilloscope (Picotech) costs an order of magnitude less ($10k versus $100k) than a 12 GHz real time oscilloscope (Tektronix) so if its limitation are acceptable, it is a good way to get the maximum bandwidth for a given cost. I admit that this compares a USB instrument to a standalone one but only because nobody bothers to make low end standalone sampling oscilloscopes and the difference between USB and standalone is not $90k dollars. Does anybody make a 12 GHz real time USB oscilloscope?An unusual feature of the PM3340 which makes it more general purpose than most sampling oscilloscopes is that it incorporates vertical delay lines (page 4-201 of the operating manual) allowing the triggering edge to be displayed. The delay lines are ultimately what limits the input bandwidth. The similar but older Tektronix 7S14 also includes delay lines limiting its bandwidth to 1 GHz. Most sampling oscilloscopes require an external delay line to view the leading edge unless a pretrigger is available. The exception is sampling oscilloscopes which support random sampling but I only know of two examples and they have their own interesting issues but no bandwidth limitation except for the sampler.

author: wazoo
author_rank: Contributor
timestamp: November 29, 2017, 09:11:49 pm
content: hiI am recovering this post because of my progress.one year after my last reply, I am going on to repair our Philips PM3323 unit.asSaabFANsaid, the fist solution was to replace ALL axial and SMD capacitors.my first images were channels completely noise without any trace. today we can see a real signal "with noise", but is a great step forward.my brother starts changing all axial capacitors with the radial version. (he said that all of them had lost capacity.)then he checked both channels injecting a signal, following the trace up to the ADC board(the signal looks "good" and now the problem was on ADC board (P2CCD). no input channels broken/burnt )and then I changed all the SMD because of the same failure, all capacitors were completely "decap" and with leakage under them.now we need to check what is the noise reason.great, we are very happy !!I know that today there are better oscopes, more portable and lighter, but I do not spent money for this unitit was on road to the trash.it could be a great tool for a RF entusiast as my brother, because this unit has native 50 ohm input and up to 300Mhz !!(apology for my english but hope you will understand)capacitor removed with leakage nearnew capacitor and cleaned sectionsome axial cap replaced with radial version

author: SaabFAN
author_rank: Frequent Contributor
timestamp: November 29, 2017, 09:16:18 pm
content: You should check out the PM3320 Repair-Thread I opened some time ago when I had to repair my unit.It now also contains some ideas and reports on how to upgrade the Processor of the instrument, which is a bit weak to be honest.Link:https://www.eevblog.com/forum/repair/repairing-an-old-pm3320a/

author: wazoo
author_rank: Contributor
timestamp: November 30, 2017, 09:48:36 am
content: ok, thankUSaabFANthen I will reply on the other Thread betther than this.sorry to re-open this old one.

author: David Hess
author_rank: Super Contributor
timestamp: November 30, 2017, 11:37:34 am
content: I see that those capacitors really leaked. They may have caused printed circuit board damage or at least high leakage which is going to cause problems.