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-   -   Philips/Fluke Oscilloscope (https://www.vintage-radio.net/forum/showthread.php?t=161330)

joebog1 12th Nov 2019 2:00 am

Philips/Fluke Oscilloscope
 
Good morning all.

I am in need of some help please.

I have 3 Philips/Fluke Oscilloscopes Model PM3055. 60 Mhz, dual timebase, LCD operating parameter panel. All have just died through lack of use. I do use them, but I may not build anything, or have anything to repair for some months. These CRO's just sit on my equipment trolley and do nothing. I have just tried all three of them and they don't work. I have a service manual on its way in the mail, so it's not in front of me at present.The whole CRO is digital in concept although of course the amplifiers are linear.

I was hoping that somebody here has had experience with these CRO's or similar types, and if there was a "common" fault? Especially stemming from non use. Power supply is I admit scary to even look at. A large PCB with several hundreds of components, although they are discrete rather than SMD, so I can at least see them and read values.

This initial post is to see if there is knowledge in the brains trust. If necessary I can even pay for help, although as a pensioner I don't have much.

Thanks to all in advance

Joe

Ed_Dinning 12th Nov 2019 9:21 pm

Re: Philips/Fluke Oscilloscope
 
Hi Joe, I think this was a fairly common industrial scope, so with luck the manuals should be available on line. Hopefully you can make 2 out of 3.

Cheers, Ed

WaveyDipole 12th Nov 2019 9:55 pm

Re: Philips/Fluke Oscilloscope
 
If these are anything like my PM3094 and with the vertically mounted cards, then the cards may just need re-seating, particularly the power supply board. I had a similar scare a while back then mine 'died' (powered up but nothing on the screen) and reseating the boards seemed to cure it. Its an odd co-incidence that all 3 would fail though. I've been meaning to strip mine down to have a look at the underside of the backplane in case there are any dodgy joints, then I got ill and the cold whether set in.....

I also found recently that the backup battery had failed and the scope de-focussed to such a degree that nothing was visible on the screen. I was able to bring it back into focus with the Focus control, but again, it had me worried for a couple of minutes. I have been meaning to ask whether these are a common problems with Philips scopes.

Ed is correct. You can access and download the manual in multiple formats here:

https://archive.org/details/philips_...z_Oscilloscope

BTW, I know what you mean regarding that power supply board. It does have a lot of caps and other parts. I would be dreading to have to re-cap it!

kevinaston1 12th Nov 2019 10:04 pm

Re: Philips/Fluke Oscilloscope
 
Hi Joe,

It will almost definately be the power supply. I have just had a look at the service manual, and it includes a full schematic and a circuit description.

Sorry, I have never repaired one of these. We did have its big brother, the PM3295 350MHz beast, which blew both its power supplies. After I had recovered consciousness when Fluke quoted the price for a replacement power supply (no data was given in the service manual for this model to repair it, and all the semiconductor part numbers rubbed out); one of my techs built a multi output linear power supply for it, which he housed separately, connected to the Philips by a multicore cable, and a locking plug assembly.

It was well worth the work as the scope had gave blistering measurement performance.

Kevin

WaveyDipole 12th Nov 2019 10:14 pm

Re: Philips/Fluke Oscilloscope
 
Quote:

Originally Posted by kevinaston1 (Post 1191160)
After I had recovered consciousness when Fluke quoted the price for a replacement power supply...

:-D :laugh2: :laugh1:

Quote:

Originally Posted by kevinaston1 (Post 1191160)
It was well worth the work as the scope had gave blistering measurement performance.

I haven't tested this exhaustively, but my unit also seems to have pretty good measurement readings and a nice clear screen, so would tend to agree.

joebog1 13th Nov 2019 2:57 am

Re: Philips/Fluke Oscilloscope
 
1 Attachment(s)
Thanks to all those who answered! Especially WaveyDipole for the link.

I actually have a hard copy in the mail.

BUT ploughing on, I might actually work out how to remove the power supply board from its "clips". It is a vertical PCB, but doesnt seem to be plugged into any mother board. There are numerous "flat" cable with IDC connectors at each end. EHT comes from a TV type tripler mounted on the power supply board.
The only horizontally mounted PCB seems to be associated with the vertical amplifier inputs. There is another small board mounted on top of the CRT, but actually physically held in place by more plastic "tabs". Bend them slightly to release the edge of the PCB type things.

BUT !!! after removing the top and bottom covers of unit one I find gecko eggs !!! Three of hem so far.

https://en.wikipedia.org/wiki/Common_house_gecko

They are extremely common and have nothing to do with
cleaning or hygiene !!
The eggs are extremely fragile as evidenced in the photo
Anway I do know that the power supply protection circuits work !:laugh1:

I will have to strip these units and "gecko proof" them, although I have tried to do this in the past with little effect as they seem almost magical in their ability to enter where they shouldnt be.

I will keep you posted.

Joe

joebog1 13th Nov 2019 3:34 am

Re: Philips/Fluke Oscilloscope
 
After downloading the service manual I find that the instructions for "breaking into " the unit is missing. Yes I am gettin on a bit, but I cannot figure out how this plastic LEGO toy comes apart. Section 12 is missing, but is entitled "Dismantling the instrument".

I can remove all the boards, but NOT the power supply. Anybody know how this is done?
I can supply photos if necessary.

Joe

Diabolical Artificer 13th Nov 2019 6:59 am

Re: Philips/Fluke Oscilloscope
 
These are good scopes, I remember seeing a bloke fix a similar Philips scope on Youtube, they were a detailed series of video's, might be worth a shufty Joe.

Andy.

IanG3XYV 13th Nov 2019 12:18 pm

Re: Philips/Fluke Oscilloscope
 
Joe,

I have a couple of PM3055s and like them a lot. They are both used occasionally and working well so I've had no need to delve into them. However I have experience of a couple of earlier Philips scope - PM3217 and PM3264. Both had power supply faults, the 3264 I think with the infamous Schaffner/RIFA mains input capacitor failure and the 3217 with the dc to dc switched mode PSU. Philips love those PSUs to supply all the dc rails and I imagine that in the 3055 will be similar. I think I had to replace one of the highly stressed switching transistors and/or diodes as well as the IEC input filter unit.

It's very much an analogue scope but with a microcontroller using the I squared C Philips bus to lots of the leg work like Autoset.

Thanks to Waveydipole for posting the link to the manual - I'd never found one before. Unfortunately as is often the case, it's not complete, but there is a bit of guidance on PSU troubleshooting.

Good luck and do let us know any progress.

Ian

WaveyDipole 13th Nov 2019 4:35 pm

Re: Philips/Fluke Oscilloscope
 
That's a nuisance that section being missing. I did find this EEVblog thread which mentions that there are two tabs on the underside of the scope, but even this poster had some difficulty removing the board on his scope:

https://www.eevblog.com/forum/repair...-and-teardown/

Seems the arrangement is a little different on my PM3094 so it perhaps needs someone with experience of this specific model to advise.

joebog1 13th Nov 2019 11:31 pm

Re: Philips/Fluke Oscilloscope
 
2 Attachment(s)
I did find the complete manual here:

http://www.qsl.net/vk5bar/AHARS-Reso...e%20Manual.pdf

195 pages.

The power supply board wont come out until the carry handle is removed!! There is even a large hole in the PCB to accommodate the handle. Removing the circlip that holds the handle on the power supply side is also a frustrating thing.
The RIFA cap hasnt blown yet but does have the crazed cracks all over it so it will be replaced. As one can see, there are lots of caps to be replaced. This CRO is from about 1991 so 30 years I would expect most of the smaller caps to be a bit weak on ESR. I will now have to order the bits, as I dont keep many sand voltage rated caps on hand. As usual Philips have used MOSTLY 68 uF, 680 uF and 6800 uF, a value thats not so easy to come by.

Ill keep you posted

Joe

Station X 14th Nov 2019 10:36 am

Re: Philips/Fluke Oscilloscope
 
One post moved to a new thread here:-

https://www.vintage-radio.net/forum/...d.php?t=161381


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