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Philips VCR948

This Philips VCR948 is still in mint condition and works as advertised when powered on. BUT...after 5 minutes it starts a life of its own. When commanded to the PLAY mode it starts spinning something but the tape is not pulled around the drum. Recycling main power does not help. The only cure is to let it sit unpowered for a few days and then the problem develops as before.

The cassette pull-in motor and its worm and angled gears are OK. I donot have schematic of its PSU but probing its outputs with an oscilloscope shows some DIGI jumps on its 15 VDC line. Allthough I have a dozen of Philips VCR PSU's floating around none of them is pin compatible to the VCR948

Is there any info on this failuremode ? Is there a look a like VCR schematic available ?

TIA

--
Bram...
If you want to grow old as a pilot, you have got to know when to push it, 
and when to back off...(Free to Chuck Yeager)
Reply to
Bram Stolk
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Reply to
Boba

sounds like bad caps,check power supply for high ESR caps

Reply to
rb

You may be right, I do have an ESR tester and I'll start checking these Limited Life Time Components one by one someday. Unfortunately my crowbar method by massive heating and subsequent freezing the bastards did not reveal any clue.....

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Reply to
Bram Stolk

cam gear.

Reply to
montech

cam gear.

Reply to
montech

I don't think it's a mode switch as the OP said "The only cure is to let it sit unpowered for a few days and then the problem develops as before." I'd still say bad caps..............

Reply to
rb

This type of Turbo-deck VR948/02M does NOT have a regular ModeSelectSwitch under its modecamgear... I just completed checking the CAPS in the PSU for high ESR, the majority is

220UF 25V they all come out OK. I noted that after a while of normal ops inPLAY mode it looses tracking and color, while at the same time the Capstan speed becomes irregular, sometimes even resulting into playback at about twice the normal speed.

Dirty videoheads or Sync/audio heads are excluded as cleaning does not help and as said before...leaving the set powered down for a few days restores normal ops for 5 minutes or so... Brute Force Heating or Cooling as well as inducing hi-g shocks has no effect. It is hardly to understand why this machine has so much ELCO's on its mainboard...

I noted it was made in Germany, I wonder where the design was done......

"montech" schreef in bericht news: snipped-for-privacy@i39g2000cwa.googlegroups.com...

Reply to
Bram Stolk

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