UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Computers

Notices

Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

Reply
 
Thread Tools
Old 25th Feb 2022, 5:53 pm   #21
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,154
Default Re: Genuine DS1210 NVRAM controllers

Quote:
Originally Posted by SiriusHardware View Post
Unfortunately, 50Hz-AC is not one of the signals available on the MK14 rear edge connector, not even on the issue VI.
That might have to be added to the rev 1.3 wish list
Slothie is offline   Reply With Quote
Old 25th Feb 2022, 10:59 pm   #22
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 786
Default Re: Genuine DS1210 NVRAM controllers

I remembered wrong, I didn’t find the schematic, but looking at an old set of notes it was using a comparator on the unregulated supply feed to the 5v regulator, so it would give advanced warning of power fail.
Mark1960 is online now   Reply With Quote
Old 26th Feb 2022, 12:35 am   #23
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 8,297
Default Re: Genuine DS1210 NVRAM controllers

I think it might be too installation specific, there's no standard MK14 power supply, or rather there is but almost no-one bought one. I use a very well regulated 7.5V linear supply so there would be almost no ripple for such a circuit to detect the absence of.
SiriusHardware is offline   Reply With Quote
Old 26th Feb 2022, 2:03 am   #24
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 786
Default Re: Genuine DS1210 NVRAM controllers

It wasn’t detecting the ripple, just a comparator to detect the input to the regulator dropping, this reset the z80 before the 5v supply started to drop.
Mark1960 is online now   Reply With Quote
Old 26th Feb 2022, 9:15 am   #25
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 8,297
Default Re: Genuine DS1210 NVRAM controllers

That's OK as long as the input supply voltage has generous headroom between the unregulated input voltage and the minimum input voltage so you could aim for a shutdown input voltage of (say) 8V if the unregulated input is normally no less than 9V on full load.

On mine, where I have the difference between input and output volts as low as possible I would have to set / choose the threshold voltage very carefully.
SiriusHardware is offline   Reply With Quote
Old 26th Feb 2022, 12:55 pm   #26
Timbucus
Octode
 
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,159
Default Re: Genuine DS1210 NVRAM controllers

The PE Champ has a discrete component Power Fail detect and Battery backup for its low power 5101 RAM chips. You can see this in the diagram at the bottom of Page 108 of PE October 1977

https://worldradiohistory.com/UK/Pra...cs-1977-10.pdf

It basically controls one of the Intel 3205 1 of 8 decoder chips enable lines (E2 pin 5) so the RAM's cannot be selected.

For those who do not know this old Intel chip this site has a link to its datasheet - along with other geat resources:

https://inttel.blogspot.com/2011/01/...processor.html
Timbucus is offline   Reply With Quote
Old 26th Feb 2022, 2:39 pm   #27
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,154
Default Re: Genuine DS1210 NVRAM controllers

I remember buying that issue of PE in WH Smiths I was hoping to build the mastermind game, but never did. I wanted to build the Champ too, but that would have involved persuading my dad to finance it, and that wasn't going to happen because he wssn't into digital electronics at the time.
Slothie is offline   Reply With Quote
Old 26th Feb 2022, 4:15 pm   #28
Timbucus
Octode
 
Join Date: Mar 2019
Location: Barry, Vale of Glamorgan, Wales, UK.
Posts: 1,159
Default Re: Genuine DS1210 NVRAM controllers

I am trying to gather the bits in the background to build one - if anyone has the acres of veroboard or soldercon pins needed give me a shout - I will start a thread. EDIT:The PE Champ I mean...

Last edited by Timbucus; 26th Feb 2022 at 4:28 pm.
Timbucus is offline   Reply With Quote
Old 26th Feb 2022, 6:29 pm   #29
Mark1960
Heptode
 
Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
Posts: 786
Default Re: Genuine DS1210 NVRAM controllers

Quote:
Originally Posted by Timbucus View Post
It basically controls one of the Intel 3205 1 of 8 decoder chips enable lines (E2 pin 5) so the RAM's cannot be selected.
The power fail circuit goes direct to the active high chip enables of the 5101 ram. Its not clear if the 74L00 is powered from the battery backup supply, it probably isnít.
Mark1960 is online now   Reply With Quote
Old 17th Mar 2022, 5:33 pm   #30
Michael - K8LH
Triode
 
Join Date: Dec 2021
Location: Michigan, USA
Posts: 33
Default Re: Genuine DS1210 NVRAM controllers

Just wanted to report that I received a batch of five (5) DS1210 ICs from this Vendor ($4.03, including shipping) and all five look new and tested ok.

Regards, Mike
Michael - K8LH is offline   Reply With Quote
Old 18th Mar 2022, 7:05 pm   #31
Phil__G
Pentode
 
Join Date: Mar 2011
Location: North Yorkshire, UK.
Posts: 232
Default Re: Genuine DS1210 NVRAM controllers

Weird, they wont ship to the UK!
Phil__G is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 3:23 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.