Phillips PM3217 Scope re-cap Howto

[dazz1]

Hi
Here are some photos to help guide anyone wanting to rec-cap a Phillips PM3217 scope.  The manual was printed 1983 so this scope is probably around 30-35 years old.
I had this one sitting in storage for 20 years before I recently had a need for it.  When I powered it up, it sluggishly started but it worked.  I decided to replace all the electrolytic capacitors.    It would cost more than the scope is worth but was cheaper than a new digital scope.

I used almost all radial caps sourced from Element14.  When doing these sorts of mods, I like to try and keep the factory appearance so the job doesn't  look like a hacked bodge.

The tinted blue screen cover was faded to a horrible urine colour so I replaced that with clear plastic covered in 2 layers of blue tinted headlight adhesive film.  It is not as blue as the original but it has the same effect.

I also replaced the trailing power cord with a IEC connector.  A worthwhile mod.

Here are the before images.

Dazz

[dazz1]

Hi
Here are images showing the insides.
You have to take the front panel out to get to the caps on the main board.
Make sure you sketch where all the connectors are that have to be disconnected.  Pay attention the the Y potentiometers. 
Just follow the instructions in the manual to remove the front panel.

Dazz

[dazz1]

Hi
And some more internal shots with all new caps. 

Dazz

[dazz1]

Hi
And the finished scope.  CRT trace is razor sharp.
It needs calibration and the probe adjusted but it works just like new.
It should be good for another 20-30 years. 

Dazz

[samnmax]

Very nicely done! I have the same one, but I've only replaced the mains filter cap (inside the transformer box in the back cover) because it was sweating some nasty liquid.

[dazz1]

Hi
I checked that filter cap on mine.  It is gray plastic and OK.  The yellowish transparent plastic ones explode when old.

Dazz

[HighVoltage]

Nice re-cap job.
But ... did you really find any bad caps?
It would surprise me, since Philips always used very high quality caps out of their own production.

 

[dazz1]

Hi
I didn't look for bad caps.  I just changed them all for new, high quality caps.    Lifting one end of each cap for testing would have taken about the same time and replacing it.

There was at least one bad cap on one channel because it took a minute or two longer for the channel to display.  I could have spent time tracking down the exact faulty cap(s) but I didn't.  This fault got fixed with the recap.

Dazz

[HighVoltage]

Thanks, nice to know, that even a Philips cap can get bad.

I only had a bad cap once in a power supply board of a Philips scope.
Usually they do not break.

[PKTKS]

Thanks, nice to know, that even a Philips cap can get bad.

THEY DO!  It depends on the source of manufact.

Philips has gone from a "dominating" era on the 80/90
to an almost cloudy obscure IP thing when they become "NXP"

Their TDA series can be found everywhere  including even SONY devices
Their datasheet manuals from the 80/90 are remarkable reference parts.


BTW the good thing about 80/90 is ..

** ALL THE ELECTRONICS ARE STILL SERVICEABLE **

you can NOT say the same from devices today.
Almost  gone if they fail seriously

Paul

[dazz1]

Hi
Here some reference photos I took of the various connectors.  I used these to make sure all the connectors were correctly connected after recapping.

[dazz1]

Hi
And some more reference photos.

[dazz1]

Hi
Attached is a BOM for the caps needed to recap the PM3217.
These part numbers were valid when I did the job but will need to be checked by you.

[Haenk]

The axial blue Philips are mostly trash, even as NOS parts. Replace on sight.

[Squarewave]

For C203, the RS part number is a Vishay capacitor. Was yours two or four pin? Does it sit ok without the other two pins for support?

[jdragoset]

Has anyone done a Philips pm 3240 recap?
So far I have only changed the two 0.22 uf Rifa smoke bombs an the AC mains.

[Squarewave]

Has anyone done a Philips pm 3240 recap?

Probably, but this is a 3217 thread.

[dazz1]

For C203, the RS part number is a Vishay capacitor. Was yours two or four pin? Does it sit ok without the other two pins for support?

Hi

I think you are referring to the big fat cap.  If so, I could not find a pin for pin compatible part.  I drilled holes in the PCB for the replacement part pins and glued the cap to the board.  I then soldered links between the pins and the pads.  It is still working, no problem.