Fluke / Philips PM3394A Combiscope preventive maintenance

[shakalnokturn]

I recently got a bargain on a PM3394A Combiscope that I expect to be holding onto for some time and use as an excuse to thin the herd a little.

The graticule illumination is dead I'll see how I can fit some LED's there, the memory backup battery is going to get some form of Lithium replacement as I hate the mess batteries and their holders finish in these days.

Are there any common problems that I should look into such as recapping, checking heatsinks and others while it is open?
I'm mostly bothered about things that could cause cascade failures leading to PCB damage or destroyed ASICs.

I read somewhere that these scopes had software issues (bugs?) what is the latest/most stable software around?

What are the main differences other than esthetics between the 3394 / 3394A / 3394B models?
What's available as software/hardware options?

[srb1954]

I have PM3394 and have had very little trouble with it in the 25 yrs I have owned it.  It is a very nice scope and is still the main scope I use for day-to-day fault-finding work. It is only on rare occasions that the PM3394 can't handle the job and I have to pull out one of my big Tektronix 7000 scopes for the more tricky scope measurements.

The S/W seems generally solid. The only aspect of the S/W that I don't like is the velocity acceleration on the rotary controls. This starts out very slow and accelerates very, very rapidly making it difficult to quickly and smoothly adjust the settings.

After 25 years use the only H/W failures I have seen are:
   1. Erratic operation on one of the front panel push-buttons. Probably needs cleaning or replacement of the carbon button on the keyboard diaphragm.
   2. Failure of the probe sense contact ring on one of the original scope probese. This is due to a spring in the probe retention collar losing pressure. The scope itself is fine.

I wouldn't bother upgrading the batteries; just check them periodically. I am still on the original set of batteries after 25 yrs. There is no sign of leakage and they still read more than 1.5V.

Options listed in the catalog are:
   1. IEEE488 (GPIB) interface in place of the RS-232 interface.
   2. Extended memory
   3. Math Plus S/W (includes FFT and other mathematical operations
   4. Aux ouput and external trigger.

All options were factory fitted and were not retrofittable. However, if you are prepared to do some soldering/desoldering on the processor and interface boards you could probably implement the upgrades yourself. This would require you to have copies of the appropriate EPROMs containing the necessary S/W. 

[shakalnokturn]

Thanks for the input.

The Math Plus would be interesting to have, I don't care that much for FFT itself but like to have a little more available than just add/sub operations between channels.

Here's what my 3394A reports for options as well as having GPIB and RS232 on the rear. (So as for HW options it looks good...)

Any idea on how to get hold of Math Plus? I've checked KO4BB's site there are no FW images there.

[srb1954]

Can't provide any suggestions for getting the S/W upgraded. The flash memory seems to require loading of different version of S/W for each option.

The service manual says the unit has to be returned to the service centre for getting the S/W reloaded when a new memory chip is installed. The service manual also states that the reloading process is done under control of a program running on a PC so I assume there is no built-in provision within the PM3394 S/W or H/W for firmware updates.

The math plus option provides: add, subtract, multiply, filter, integrate, differentiate, FFT, histogram, enhanced probe scaling, pass/fail testing, measurement statistics, enhanced cursor measurements and multiple single-shot captures

[HighVoltage]

I have about 20 of these scope around and they can be really good workhorses, even these days.
These old Philips / FLUKE scopes have a few befits that you don't have on modern scopes.

Make sure to press the CAL button often for autocalibration, before the CAL would run too far away
and it would require hardware repair.

A new set of batteries easily last 10 years.

Keep the dust out of the system. I open my used scopes of this series once a year and blow them out.

The light is a simple light bulb, but hard to get these days.

Remove the front blue protection screen from time to time and wipe it clean

Not much else.

The original software to download images and control the scope still works over RS232
It worked best on the 3394B but also works on the A Version
If you don't have the full software, let me know and I can send it to you.

These were amazing scopes at the time, only appreciated by those who used them.

I bought my first brand new one of these in 1996

[EHT]

Just got my PM3394 in relatively good order. My points on this topic:

- I replaced C1001 X Capacitor to avoid it exploding (can't recall if it was originally a RIFA foil type or not)
- I guess the line filter should also be replaced for the same reason in case it has foil X/Y caps in it BUT the cable operated on/off switch is integral... I can't see any useful markings on it to identify the brand and the part number doesn't come up with anything in Google. Anyone replaced it or know if it is safe to leave? It could be bodged with one having the same panel dims, sacrificing the front panel power sw.
- I need to replace the illumination lamp. I can see few 28V ones which look similar labelled "T1 3/4 midget"  with types flange/wedge/groove...
- As mentioned in above posts it would be good to have the remote terminal software to manage the calibration data stored in flash over RS232. I'd at least like to know how cals are left (maybe it says before saving?). I believe the same annoying system is used in the Fluke 90 series scopemeters
- Ideally I'd like to have the ROM version that supports GPIB & Math

[HighVoltage]

I think I still have a light bulb from year ago when I bought a few before they became unubtanium.

Is yours a "A" or "B" version?
The hardware has changed from the "A" to the "B" Version and ROM images are not compatible.

The later "B" versions were the best with the latest software from 1998-05-04
This is a screen picture of a 3394B, with all options and latest FW.

[EHT]

Hi, I see a few small 28V bulbs on Farnell so maybe one type is right? I should take it apart again and see...

Mine is an A which has had quite a number of hardware mods applied. It does have the GPIB connector but the ROM image is not the original due to a previous ROM failure. 

[Vince]

Great topic ! Love these scopes, thanks all for the information 

Shakal, have a (Philips branded) 3394A too, though yours is much more recent, FW is over a year and half younger than mine.

Also have a 3384B (Fluke branded).

I love these "hybrid" scopes, great general purpose scopes that work fine for 99% of the stuff.My fancier digital scope don't need to be fired up that often. The combiscope is quieter, less power hungry, starts faster, and has that analog capability when you want it.

I used to use a Tek 2232 but it didn't like the house move and has developed an issue with the focus.. the control now only let's me choose between a trace/readout of thickness between 5 to 10mm !    Not very usable... will get round to fixing the 2232 of course, but too busy working on the house. So in the meantime I switched to using the Combiscope.  I can then compare the 2, and appreciate the good in each of them.

Generally speaking I prefer the Fluke / Combiscope because it's 5 years younger in design, and it shows. Less " temperamental ", more sophisticated features and user interface, a bit more memory.. and 4 channels instead of two.

The 2232 however wins (for me at least), in the user interface department. I find the controls and menus so much more intuitive to use. It's a breeze. The Combiscope here and there, is a pain. Some menus baffle me and I have to think 10 times to figure out what button or knob to use, and in what direction to turn it, in order to get the desired result. Also, as has been already mentioned, and I agree 100%... the acceleration of the rotary knobs leaves a lot to be desired. Either too slow or too fast, no middle ground. Drives me a bit nuts and wastes time.
Also too many push buttons.. I keep having to stick my nose on the front panel to read all the button labels to find the button I want. My brain just can't build a "map" of what button does what. Again waste of time.

Also, the sampling rate on the combiscope is not great. It's even lower than the 2232 even though it's years more modern. 250MS/s for the 2232, on each channel, and only 200MSps for the Fluke and I fear it's multiplexed ?! So since it's a 4 channel scope, that means possibly only 50MSps per channel vs 250 for the Tek. I have a copy of the original paper manual for the Combiscope, and could not find clear information stating whether or not the 200MS were shared / multiplexed.

But other than sometimes questionable user interface decisions, overall the Combiscope is my favorite. Also, big advantage of course is the combiscope offers automatic measurements, and math functions. 2232 does not.

Both my A and my B have the FFT / Math package it appears.

As for the differences between the A and the B : I stacked them on top of one another, fed them with the same signal, and then entered each and every menu and sub-menu, to hunt for differences. Could hardly find any.. same exact menu items everywhere, same memory depth, same everything. Only difference I found are :

- The 3394A (200MHz) has a 50ohms option which the 3384B (100MHz) does not.
- The 'B' has a lot more driver options for plotters and printers.


So I use the older 'A' scope because of its 200MHz B/W and 50ohms option, but at some point I will want to use the plotter and printer output, as I would love that to document my work. I am tired of taking crappy pictures of the screen with my camera. It never looks nice.

Since I understand from above comments that the A is not compatible with the B F/W... I am out of luck.... unless your 'A' which has a much more recent F/W than mine... would happen to have the plethora of printer drivers that my B does. I could reflash my scope with your F/W ! 

As for calibration needing to be done regularly... I notice that my scope takes care of that himself : it interrupts me regularly to run a calibration whether I like it or not ! 

As for batteries, RTC is still holding up after 27 years !    So good batteries they must be ! I guess I should none the less open the scopes to make sure they are not starting to leak...

I have to say I got lucky and both my scopes somehow were working 100% fine, so I didn't need to open them up ! Don't even know what they look like inside, shame on me !     I am used to old Tek scopes, but I have no idea about the guts of these Combiscopes...


@HighVoltage : might it possible that you send me a copy of the computer S/W for these scopes ? That would allow me to take care of them... and let ShakalNokturn read his F/W, so he can send it to me and then I can reflash my scope to get the extra printer drivers ! That would be awsome 


Anyway, was great to see a topîc on these scopes, I have grown quite fond of them, might buy some more of them if I ever come across cheap broken ones. A 3394B would be good.

[HighVoltage]

@HighVoltage : might it possible that you send me a copy of the computer S/W for these scopes ? That would allow me to take care of them... and let ShakalNokturn read his F/W, so he can send it me and then I can reflash my scope to get the extra printer drivers ! That would be awsome 

I think I posted it it some thread
Let me look for it and I will post it again

[Runco990]

The Combi scopes are pretty cool.  I actually sold mine recently because I just moved "up" in scopes.  I liked it.     But I strongly dis-agree on the batteries. 

Check them often and for GOD'S sake, don't use DURACELLS!!

Batteries used to NOT leak years ago.  These days...  I see them leaking still in the pack!

I use Energizer lithium AA's in all these applications now.  So far, (knock on wood) no leaking.

Just FYI.

[HighVoltage]

The original Philips AA batteries are so good, that even after 30 years, I have not seen one leak.

Attached is the original Software to download images from the scope and to control the scope over RS232
Instructions are enclosed.
Unzip, Unrar
Install the demo software  and then apply the original update.
It runs best in Windows XP but you can get to run under Windows 7 in XP compatibility mode

[Vince]

Attached is the original Software to download images from the scope and to control the scope over RS232
Instructions are enclosed.
Unzip, Unrar
Install the demo software  and then apply the original update.
It runs best in Windows XP but you can get to run under Windows 7 in XP compatibility mode

Thanks a bunch 

The only Windows I have is XP in a virtual machine under Linux. Might have to spend some time to get the virtual machine to work with the serial port.. never tried it.

If that fails I have an old Pentium  / Windows 95 machine which would be period correct for this '90s software / scope, so I guess it would work fine as well on that machine. Will see !

[kripton2035]

Quote

Attached is the original Software to download images from the scope and to control the scope over RS232

thanks but the archive asks for a password to open it ?!?!?
unzip is ok but unrar ask for a password

[mc172]

Not sure if this helps but I've got a similar-looking PM3082 and I heard the fan gradually loading up, slow down and ultimately stall one day whilst messing around with some broken kit I had to fix, so I turned it off and used my Rigol until a new fan came in the post. It was quite a slow process, not a sudden slowing down. The bearings in the old fan had gone really high friction. If I hadn't been there to hear it slow down I doubt I would have noticed.

[Vince]

thanks but the archive asks for a password to open it ?!?!?
unzip is ok but unrar ask for a password

Oops yes, just tried it, same problem. ZIP is OK but RAR asks for a password...

[HighVoltage]

Sorry, here is a more detailed install instructions

Password is my eevblog user name: "HighVoltage"

Download
Download the two zip files:
- FlukeView_Software-1.zip
- FlukeView_Software-2.zip
Unpack each ZIP file seperately

You will end up with 2 RAR file:
FlukeView_Software.part1.rar
FlukeView_Software.part2.rar

Unpack
Use WinRAR to unpack both files
use password: "HighVoltage"

You will end up with 1 ZIP file:
FlukeView_Software.zip
unpack this ZIP file and you will get two folder:

- FLUKE
- Fluke Ver 2 update

INSTALL
Copy the folder "FLUKE" to to C:\
Ending up with:
C:\FLUKE

Start the SETUP.EXE in the "Fluke Ver 2 update" folder
It will search for the FV33WIN.EXE in the "C:\FLUKE" folder and then update to v2 full version
Done!

[Vince]

Thanks for taking the time to detail this procedure HighVoltage... install is now successful, S/W starts up just fine, yeah ! 

Now just need to search for a null modem cable in my boxes full of cables !

Can't wait to connect to my scopes and play with them, thanks a bunch ! 

[srb1954]

The original Philips AA batteries are so good, that even after 30 years, I have not seen one leak.

I have had the same experience with the Philips AA batteries in my Combiscope: more than 26 years, no leaks and still reading more than 1.5V per cell.

These cells are marked "Made in Belgium" so in the past someone in Belgium knew how to make a quality battery. I wonder if that person can be found and brought out of retirement because all of the current battery manufacturers have forgotten how to make a decent battery.

[shakalnokturn]

Vince:
I've been planning on dumping the firmware from my PM3394A since the beginning of this topic, now if you're actually in need of it that may get me moving (hopefully the containers are socketed).
I'm still interested in trying out the Math Plus if I can get hold of that.
Any chance you'd go to the trouble of doing a dump too?
I'll update the topic one evening when my scope is open with a bit of luck we'll be able to swap and experiment at the same time.

[Vince]

Shakal, of course I don't mind doing whatever that may help you ! ... but I don't have an EPROM programmer just yet... house construction is my priority for now (just finished painting the bedroom this evening, making progress !  ). However I could just ship the EPROM to you in the mail, no worries.

But I just realized one big problem, stupid me : if I reflash my scope with your F/W, I will benefit from the extra printer drivers, most likely, but... I would also in the process lose the Math package !    Can't afford that.

And the other way around too... with my F/W you would get the Math package but lose most of the printer drivers...

We need to find a way to add the math package to your F/W before I reflash my scope with it !

Or maybe HighVoltage or someone else here, has one of his ' A ' scopes with a recent F/W which features both the extra drivers and the Math package ?!  That would be the easiest way...

[kripton2035]

funny to see french people talking in english on an australian forum hosted in the USA ...

[2N3055]

funny to see french people talking in english on an australian forum hosted in the USA ...

[Vince]

Kripton, that's  globalization in action ! 
I quite like it.. the good side of the world "economy", bringing people together...

What's much more perplexing is seeing French people in France not being capable to speak proper French anymore, and instead spit out random English words like condiments, thinking that will make them look trendy or smart.. but in fact their English is just as atrocious as their French.. but you can't tell them because well, it's so wide spread in French society these days that it's become the norm. How sad is that...


Shakal, here the list of drivers I have in my scope, so you can compare with yours. Do you have more than these ?


Printers :

- HP 2225
- FX80
- LQ1500
- HPLaser (series II & III only)

The first 3 are dot matrix printers as I understand it.  LaserJet is cool as I have one but... I have a more modern 6 series, not 2 or 3...

Plotters :

- HP 7440
- HP 7550
- HP 7475A
- HP 7470A
- HPGL
- PM8277
- PM8278

[HighVoltage]

Now just need to search for a null modem cable in my boxes full of cables !

In the scope menu for the RS232 setup, you can select between a 3 wire or 7 wire connection.

In my experience, all you need is a 3 wire null modem cable and you can go full turbo speed on the PM3394B
but on the PM3394A you have to use reduced speed to get a stable transfer.