Anyone good with Timer/Control Logic? - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st May 2016, 03:31 PM   #1
diyAudio Member
 
giro1991's Avatar
 
Join Date: Feb 2013
Location: Scot[ch]land
Default Anyone good with Timer/Control Logic?

Hello all,

I have here a DAT deck from 87, which can fully play/record via multi-bit converters but with one minor hick-up, a timer.
Hopefully with some advice and reference to the datasheet below it can be suppressed?

CXP5058 pdf, CXP5058 description, CXP5058 datasheets, CXP5058 view ::: ALLDATASHEET :::

Short Version:
Essentially this timer prevents it to work continuously in record-pause mode, which is the only mode it can record/play - without tape.
Timer puts the main control IC into STOP mode, (from rec-pause mode) so I have to re-press REC to get the ADDA functions again, every ten minutes.

Long Version:
DAT decks have two intermediate stages to record, the first is record-pause mode (standby), once pause is released it enters record-play mode (write).

When record-pause mode is activated, the head begins to spin beside the tape thats already loaded (DAT uses a rotary drum).
In this mode for long enough, the tape would disintegrate (EDIT: Or so I thought) therefor SONY added a timer to STOP spin after 10mins.
Its a fully functional ADDA via SPDIF in this mode otherwise.

A brief eureka moment with a dummy tape, initially a work-around the inevitable tape length problem by informing logic 'tape present', was shortly countered when this timer made itself apparent.

Anyway, with a tape loaded, dummy or normal, this timer cut's out every 10min.
Releasing pause to enter write mode isn't an option; missing tape in the dummy messes with the servo's.
Normal tape can be used but operation limited to 120mins.

Full schematics are available, but the timer and modes are contained inside this IC (datasheet above).
The rec-pause/play buttons link directly to this IC and so is the best shot... (albeit a long one).

Any Ideas?
__________________
Most overlook the fact Digital Compact Cassette was DSD stream applied to MPEG compression

Last edited by giro1991; 8th June 2016 at 03:02 PM. Reason: funny to watch
  Reply With Quote
Old 3rd June 2016, 08:51 AM   #2
diyAudio Member
 
Join Date: Dec 2003
Location: Sydney
Instead of feeding an S/PDIF signal to it, can you feed I2S? If YES, why not go straight between 7220 and 1541 with I2S? This section of the recorder should always stay on (it may be affected by the 10min timer, via muting circuit, but that can be fixed quite easily). This solution would give you the best possible sound as well; furthermore, you can disconnect all other sections - including the drum with heads, further reducing negative impact of these unneeded sections on sound quality.

Fooling the logic is quite cumbersome; it can be done though, but would provide inferior results sound-wise, to what I suggested above.


Nick
  Reply With Quote
Old 3rd June 2016, 09:22 AM   #3
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
On DAT, Video8, Hi8 and Betamax machines, the tape floats on a cushion of air and does not touch the drum. The timer is there to protect the mechanism from failure. Philips brought out an ICE version of DAT but it didn't catch on.
__________________
Support for Fender, Marshall and all Valve Equipment including Audio Innovations, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 3rd June 2016, 11:59 AM   #4
diyAudio Member
 
giro1991's Avatar
 
Join Date: Feb 2013
Location: Scot[ch]land
Thanks for the advice. I considered alternative i2s interface but the level meter would be redundant then, the main reason to keep it, mainly for demonstration/education purposes.

Quote:
Originally Posted by JonSnell Electronic View Post
the tape floats on a cushion of air and does not touch the drum. The timer is there to protect the mechanism from failure.
So the spinning is to produce air? that is rather neat! But then how does the timer relate and/or prevents damage if it's designed to spin for hours in normal operation in Write record-play mode anyway? In record-pause mode only the drum is active so what does the timer prevent if it's not 'headwear'?

If it's not possible to bypass I'd sell it though it's a retro bit of gear, over-engineered in all aspects, multi-bit conversion back to front, muse caps heavyweight mechanism, copper chassis, lot's of adjustment pots etc. Would be sad to see it go...

FYI: The dummy tape was as easy as prying two 'plastic mirrors' 2mm small, situated just under the lip of the DAT tape. If you look carefully, there's on one on each side, poke them with a pointed device, to pop them out. Their purpose is too reflect light emitted from inside the drawer compartment back into a sensor, also in the compartment. When I cut the tape to 'extend' recording time the 2mm mirrors aren't blocked so inform logic 'tape not present', which disallows the next stage (record pause).
__________________
Most overlook the fact Digital Compact Cassette was DSD stream applied to MPEG compression

Last edited by giro1991; 3rd June 2016 at 12:03 PM.
  Reply With Quote
Old 3rd June 2016, 12:24 PM   #5
diyAudio Member
 
giro1991's Avatar
 
Join Date: Feb 2013
Location: Scot[ch]land
I have to press record every now and then the make record/play seamless. I was thinking maybe putting a repeating timer with 555 timer IC across the rec button and just enabling that to do it automatically.
__________________
Most overlook the fact Digital Compact Cassette was DSD stream applied to MPEG compression
  Reply With Quote
Old 8th June 2016, 03:07 PM   #6
diyAudio Member
 
giro1991's Avatar
 
Join Date: Feb 2013
Location: Scot[ch]land
Besides the 555 timer, would coupling the SPDIF signal to the REC button be feasible?

For instance, when I play signal from PC (or USB to i2S as already suggested), I could use part of this signal to re-trigger the REC button on. Because SPDIF flickers, is there some sort of component that can be used to converter the flickering to simulate me pressing REC?

Another incentive to do it this way is to work-around another problem which is I also have to re-press REC for sample rate changes.
__________________
Most overlook the fact Digital Compact Cassette was DSD stream applied to MPEG compression
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How do I configure a simple logic control poldus Analog Line Level 10 7th July 2014 12:47 PM
HV Logic Control Approach BRSHiFi Everything Else 55 8th May 2014 01:38 AM
Mute Logic for LDR volume control gmphadte Solid State 0 22nd November 2011 11:26 AM
a timer to control LED candles?????? Video Freak Parts 2 19th May 2008 12:27 PM
RS232 Relay Control (Logic) Morbid Digital Source 4 21st July 2004 03:50 PM


New To Site? Need Help?

All times are GMT. The time now is 04:24 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki