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RE: Service my Philips 212 Turntable - Part 2: initial measurements

dang74 — Sun, 09 Apr 2023 15:58:35 GMT

I enjoyed this blog. It's always interesting to see how things were designed 40 years ago. The BJT did a lot more of the 'heavy lifting' back in the day. Today of course we hear about capacitive touch sensing in the context of touch screens. It was interesting to see it here for the speed control.

RE: Service my Philips 212 Turntable - Part 2: initial measurements

colporteur — Fri, 17 Sep 2021 21:22:17 GMT

Enjoyed the presentation. I trust the jenga tower base iss temporary or your going to need a supply of needles everytime it drops. Can you purchase needles? Oh and throw out the vinyl you were playing.

RE: Service my Philips 212 Turntable - Part 2: initial measurements

neptunium — Fri, 17 Sep 2021 13:25:56 GMT

Great article! I also have a 212 in need of some care, so I've been studying the schematic as well. Two of the indicator bulbs are burned out and the auto-shutoff one is probably dead too. I may replace them with LEDs and series-parallel resistor arrangements to keep the same load. Philips actually did that in a later model so I think they would approve.

But what greatly puzzles me is why the designers have used positive ground in this system. Is there any inherent advantage to doing so compared to the ubiquitous negative ground? I've read that on older cars with a positive ground chassis it was done because it allegedly provided a better spark and less galvanic corrosion, but that doesn't apply here. The schematic feels very "upside-down" in places! [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-7bba9b51-fbd7-405d-8e4a-ba93f1fe0970/1145.contentimage_5F00_1.png:16:16]

Another oddity is the use of germanium transistors in the power supply. I'm guessing this was done for efficiency/dissipation reasons because of the lower voltage drop?

RE: Service my Philips 212 Turntable - Part 1: the defects

jbjb — Mon, 26 Jul 2021 11:09:15 GMT

Hi Jan from John in Brisbane in Australia..i have 3 good 212 tt and a good 202..bit of a collector. Amazing how they have survived 50 years

RE: Service my Philips 212 Turntable - Part 2: initial measurements

Jan Cumps — Thu, 20 May 2021 07:57:24 GMT

Not everyone appreciates a repair.

[View:/resized-image/__size/620x267/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-7bba9b51-fbd7-405d-8e4a-ba93f1fe0970/8750.contentimage_5F00_206978.jpg:620:267]

RE: Clean an ITT Schaub-Lorenz Viola radio from 1970

DAB — Mon, 21 Dec 2020 20:16:30 GMT

Good shape for being from the 1970's.

DAB

RE: Original Xbox

DAB — Sat, 19 Dec 2020 18:23:32 GMT

Nice fix.

Bringing something back to life is always a good day.

DAB

RE: Service my Philips 212 Turntable - Part 2: initial measurements

loriv — Sun, 13 Dec 2020 02:17:17 GMT

Hi! I have this exact same turntable, which my parents bought when they were in their twenties. I'd love to have it refurbished. I live in the Portland area. Does anyone here know someone who might be able to do this work?

RE: Fix that Power Supply, or bin it! - Part 2 : Troubleshoot and repair

akshitagupta15june — Wed, 20 May 2020 01:39:42 GMT

Your build is really great.

RE: Fix that Power Supply, or bin it! - Part 2 : Troubleshoot and repair

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RE: Tektronix D10 5103N analogue oscilloscope repair

colporteur — Tue, 19 May 2020 12:12:46 GMT

It sounds like the rubric cube of electronic repair to get at the components that needed replacing. You have some experience to tackle such a task. Great job.

RE: Tektronix D10 5103N analogue oscilloscope repair

ls120nz — Tue, 19 May 2020 10:18:08 GMT

well done i have a portable i need to look at that has a problem.. not sure what as was give to me by an old tech.. he didn't have time to fix it.

RE: A Shocking Variac Made a Little Less Shocking!

three-phase — Fri, 15 May 2020 19:08:19 GMT

Nice fix on the variac, they are indeed very useful devices to have around. Used by 'old timer electricians' it is not uncommon to find them with minimal safety features installed.

Kind regards.

RE: Midi Synth rescued from the junk bin

DAB — Fri, 15 May 2020 19:01:09 GMT

Good job bringing it back to function.

DAB

RE: A Shocking Variac Made a Little Less Shocking!

DAB — Fri, 15 May 2020 18:46:09 GMT

Very good variac repair.

DAB