[cctalk] Re: Papertape-Reader Decitek 442A9: need manual/schematics

It looks as though Decitek remain in business http://www.decitek.com/index.html Scan of a series 700 reader manual on bitsavers http://www.bitsavers.org/pdf/decitek/ On an optical reader, I would not recon the capstan running at power on as unusual - a pinch roller which engages for drive and a tape clamp engaging for stop motion are both common features. For simple single byte read operations, probably the paradigm used when the unit was built, it is not uncommon for the sprocket hole to stop feed and energise clamp. The circuitry to control this behaviour may be in the drive or controller or shared; and then there are configuration links / switches ... An empirical approach is to scope / LA the sprocket and data bit outputs; ideally with a tape loop. HtH; Martin -----Original Message----- From: Michael Fritsch via cctalk [mailto:cctalk@classiccmp.org] Sent: 16 May 2024 15:14 To: General Discussion: On-Topic and Off-Topic Posts <cctalk(a)classiccmp.org> Cc: Michael Fritsch <mi(a)fritscholyt.de> Subject: [cctalk] Papertape-Reader Decitek 442A9: need manual/schematics I have a Decitek 442A9 papertape reader which needs repair. I have already replaced the belt, but that is not enough. The reader behaves very strangely. It starts running as soon as I apply power. And there is another problem: when I load a tape, it rattles irregular during reading. This is not a mechanical problem, it seems to react to the pulse of the feed hole, which arrives at the wrong time. I'm pretty sure, that I have to adjust the sprockets somehow relative to the stop positions of the stepper motor. It was nothing to be found online except pictures of a similar model 443A9 at RICM: https://www.ricomputermuseum.org/collections-gallery/equipment/dec-pdp-8s-4. The controller board number is 30291A Does anyone happen to have the manual and/or schematics or any other documents? Thank you, Micha