Philips PM3207 Oscilloscope.

[Geordie McBoyne]

Bought this Philips PM3207 in the early 1980s along with other Philips test equipment. Frequency counter, DVM and a bench power supply unit.
The oscilloscope was never very reliable and in due course taken out of service. In those times I was too busy to repair the instrument.
Now it's time to repair this oscilloscope. I'll bring it down from upstairs later today.

Geordie McBoyne.

[bobhowe]

Hi David Philips been a premium brand very surprised that it has been unreliable what faults has it got kind regards Bob

[Murphyv310]

EHT transformer failure is quite common.
Not necessarily the issue here though.

[Geordie McBoyne]

Hi David Philips been a premium brand very surprised that it has been unreliable  what faults has it got kind regards Bob

Hi Bob. The PM3207 oscilloscope has many miniature relays to perform switching functions, these can be unreliable.

Geordie McBoyne.

[bobhowe]

Hi Trevor Hi David as seen on the VRAT site my Philips LED light bulb thread you think you are buying a top brand item like Philips that it should be more reliable the light bulb in question only had a years guarantee some of the cheaper brands have a 3 year guarantee kind regards Bob

[Mike Watterson]

Philips wasn't a top brand for scopes then or really ever.

But a lot of 1980s gear used unsealed budget miniature relays rather than sealed kind, no doubt cost-cutting by procurement after design.
Do a search on FT102 relays. The earlier Yaesu FT101ZD is more reliable!
https://www.radiomuseum.org/r/yaesu_ft_102.html (Approx 1982)
https://www.jvgavila.com/ft102_1.htm
Corrosion, not dust, is the issue!

So the relays would be the first thing to check, especially if it was erratic ever.

If replacement types are a different pin-out but correct coil voltage, contacts and contact rating, one idea is to use a header with relay upside down. Either custom stripboard or DIL depending on PCB dimensions.

[Murphyv310]

Ah yes the upside down relay trick .
Having a couple of Yaesu FT480R radios that is the only way to fit a modern more reliable replacement as the original types are long gone.

I concur with Michael that Philips scopes weren't the best. The one I had suffered EHT transformer failure twice!!! A known problem, the scope was scrapped many years ago. In fact my Tec scope also died a catastrophic death with major PSU failure. Now use my trusty Hitachi, simple basic and generally very reliable with occasional maintenance and calibration every 5 years.

[bobhowe]

Hi I think its time for a David Boynes adaptor plate

[Geordie McBoyne]

Murphy310 wrote: "Now use my trusty Hitachi, simple basic and generally very reliable with occasional maintenance and calibration every 5 years."
Not long after I bought the Philips PM3207 in 1982 I bought a Hitachi V-650F oscilloscope which is still in use almost every day.

Geordie McBoyne.

[ppppenguin]

My view on scopes is that they are tools to help me work on other kit. They need to be reliable and capable. I don't want to spend time working on the scopes. Been there, done that, when I was in my teens and 20s when I couldn't afford decent kit.

Some are interested in scopes for their own sake and that's fine.

My weakness is a very nice Tek 547+1A4 sitting under the bench. Can't remember when I last plugged it in. I should probably get rid of it to a loving home but a little voice says not yet.