Philips PM 3262 Oscilloscope evaluation/troubleshoot. - Page 1
Forum section: electronics / testgear

author: Pexy13
author_rank: Regular Contributor
timestamp: February 10, 2019, 07:14:05 pm
content: Greetings.I am searching for my first scope to buy and i came across this one:https://www.ebay.de/itm/Oszilloskop-Philips-Pm3262-Oscilloscope/192633781819?hash=item2cd9de3e3b:g:RksAAOSwwwRbDjEo:rk:9:pf:0Looking at the pictures I think that the scope as well as probes need to be calibrated. Or is it just because cal knob isn't in the cal position?I would appreciate if someone with more experienced eye take a look at it.Is there something that you see that tells you to stay away from it or is it just a calibration problem.Any additional information is well appreciated.Thanks, Sven.

author: vk6zgo
author_rank: Super Contributor
timestamp: February 11, 2019, 08:43:36 am
content: Quote from: Pexy13 on February 10, 2019, 07:14:05 pmThe "cal" positions on thevolts/div&time/divcontrols have nothing to do with the internal calibration of the Oscilloscope.They are provided to give a "parked" position of the continuously variable controls, where the switched controls will be in the "calibrated" state.At this point, you may ask,"Why would you need to have continuously variable controls?It seems counter-intuitive."Many times, a user may need to determine the level of a small signal as a percentage of a large one.Often, the large reference signal cannot be exactly fitted into standard numbers of divisions on the v/div graticule.The obvious answer is, using "variable", adjust the display amplitude to fit exactly to the graticule.A similar argument applies in the case of time/div.For many years, various spec tests were done by the use of "Standard graticules" .These usually required the user to fit the display into certain "reference marks" to ensure repeatability of the test.

author: Calvin
author_rank: Regular Contributor
timestamp: February 11, 2019, 09:38:42 am
content: Hi,I have a PM3268, also 2ch, 100MHz, delayed 2nd timebase.The scopes are from the late 70s early 80s , so probabely 35 to 40years old.They were intended for mobile useage also, so the devices were tested for shock and rattle ... in other words ... they were built quite solidly and to take some abuse.If it is in good condition the 85€ are not too expensive.Manuals are freely available and beeing built with discrete parts servicing is possible.Thanks to the mobility idea they feature a dc-input for battery supply.On first switch on my PM3268´s input cap of the supply blew up ... they quite often blow up and the supply is unfortunately a fully resin encapsulated subassembly.I replaced the supply by a 24V SMPS which just fitted into the old space and run it via the dc-in connection without any probs since then.Apart from that its a really good scope.jauuCalvin

author: dzseki
author_rank: Frequent Contributor
timestamp: February 11, 2019, 10:35:29 am
content: Quote from: vk6zgo on February 11, 2019, 08:43:36 amI think the OP refers to the fact that the calibrator output should be 3V as seen on the picture, but the V/div knob is set to 50mV/div, and a 3div vertical signal is seen (150mV). Considering the "uncal" LED is also lit, I think it is fair to assume the scope should work well in this regard providing a 10:1 probe was used.

author: Pexy13
author_rank: Regular Contributor
timestamp: February 11, 2019, 12:22:32 pm
content: Quote from: Calvin on February 11, 2019, 09:38:42 amThanks for the information.Appreciate it.Sven

author: Pexy13
author_rank: Regular Contributor
timestamp: February 11, 2019, 12:25:53 pm
content: I think the OP refers to the fact that the calibrator output should be 3V as seen on the picture, but the V/div knob is set to 50mV/div, and a 3div vertical signal is seen (150mV). Considering the "uncal" LED is also lit, I think it is fair to assume the scope should work well in this regard providing a 10:1 probe was used.Yes, that's what i thought.Thanks,Sven