Philips PM 3216 Oscilloscope - Page 1
Forum section: electronics / repair

author: boffin
author_rank: Unknown
timestamp: November 21, 2016, 01:59:22 am
content: Does anyone have the service manual (PDF) for this? I've got close with a 3226 manual, but that's not the same thing.

author: oldway
author_rank: Super Contributor
timestamp: November 21, 2016, 05:58:56 am
content: I think the PM3215 is very close but 50Mhz instead of 35Mhz.http://elektrotanya.com/philips_pm3215_u_sm.pdf/download.htmlWait for "processing" became "get manual"Most common failure of this serie of oscilloscopes is a faulty SMPS ferrite transformer. (HV coil with internal turns/layers short-circuit)No easy solution to repair this.Here you see a repair I did on a PM3214: I removed the HV coil and add a home made board with HV oscillator.

author: boffin
author_rank: Unknown
timestamp: November 23, 2016, 10:02:33 pm
content: Quote from: oldway on November 21, 2016, 05:58:56 amDo you have some more photos, I might have exactly the problem you had.I pulled it apart finally today, and while I get the -30 off the initial transformer/full wave, I'm getting about 2/3 of the voltages I should be getting on the the main voltage legs after the main transformer (like 3v instead of 5, 120v instead of 180v). See the attachment to let me know if this is what had failed on yours...

author: oldway
author_rank: Super Contributor
timestamp: November 24, 2016, 10:12:30 am
content: QuoteNo, absolutely not !It was the big ferrite transformer, the HV coil had an internal short circuit between layers.On the pictures, you can see how it was ...I removed the orange isolation compound and removed the HV coil (external coil of the transformer)Here another thread on this problem.https://www.eevblog.com/forum/projects/reviving-a-phillips-pm3212-osciliscope/I think Mediarocker never succeeded repair his PM3212 as he never returned to give us informations about this repair.http://i11.photobucket.com/albums/a163/MediaRocker543/IMG_20121010_172440.jpg

author: boffin
author_rank: Unknown
timestamp: November 26, 2016, 03:57:54 am
content: I know you were all dying for an update. Maybe 2 or 3 of you?OK, I understand, no one cares.YAY ! It looks like I've found the culprit. a 220R trimmer that is showing 1k5 across it. Big problem when that's the trimmer that adjusts the main voltage supplies for the scope.Didn't have one in the parts bins, but put in a 100R and 120R just to see what we get and we're pretty close to where we should be (11V on the 12V rail), so I'll pick up the real thing at Lee's tomorrow.Going to swap out the two 30V bulbs for the graticule illumination with 5 Red (because it looks cooler than white) LEDs tomorrow as well.

author: boffin
author_rank: Unknown
timestamp: November 26, 2016, 11:47:09 pm
content: Ok, here's the final followup.The old trimmer for the voltage, which was supposed to be 220R turns out to be about 1k5 from end to end, so went out this morning and bought some new 220R trimmers, turns out one of them isn't anywhere near 220R (160R), but the other two were 210R, close enough.Also, replaced the the graticule illumination (2 incandescent bulbs) with 5 red LEDs w/ 2k in series, which solves the problem of the graticule illumination, with new sexy red.Need to pick up some better contact cleaner and have a good go at channel 1's Y controls (which only work if you wiggle and have exactly the correct tongue angle), but channel 2 is working like a charmScope: $10Trimmer: $1Getting a working scope for less than a case of beer: Priceless

author: tautech
author_rank: Super Contributor
timestamp: November 26, 2016, 11:56:42 pm
content: That's quite cool, thanks for sharing.