[Coco] tandy 1000 ex/hx external 720k drive to use on coco

Fri Jun 19 23:34:11 EDT 2015

On Friday 19 June 2015 21:57:56 Bob Devries wrote:
> Hi Gene,
>
> Actually, if you search for disk drive power adapter on eBay, you'll
> find a SMPS with a 4 pin plug suitable to connect to a 5.25" drive.
> They vary in output power ratings, but have both 5v and 12v.

I'd guess a good search could probably come up with something, but how 
does that compare to an escapee from a 25 yo xt?  Probably many times 
the cost, where the xt supply was built back when they expected them to 
run forever and could be extracted free from a curb pickup 20 years ago.  
Very few of the supplies available today haven't been engineered to fall 
over 2 months after the warranty expires, which of course keeps many of 
the name brand psu makers in business.  I had 3 different Antec supplies 
in this machine, all grossly larger that it needed.  All failed shortly 
after the warranty expired because the output voltages faded out of 
tolerance. 53-54 weeks. So a friend, who was in the pc service business 
at the time, and who had been buying psu's in case lots from some 
Chinese maker for about $12/copy, sold me a 300 watter, said it was big 
enough even with 4 Terrabyte drives spinning.  300 was half of what the 
Antec's were.  That was like 5 years ago, and gkrellm says every voltage 
is still well within tolerance. 5.11 on the +5, 3.40 on the 3.3, and 
VCore for this Phenom is still at the 1.29 volts I set it to 5 years ago 
trying to cool it a bit.  CPU temp 43C atm.

Last time I checked the 5 volts on that old xt supply my coco runs on, it 
was the same 5.13v it was 25 years ago.  The gamers fav, an Antec, I 
would have had to replace 20 times by now.  At a total of around $2000 
since they want a hundred for the name.

I guess I'm getting on Bob, but my theory is, if its not broken, I don't 
fix it, so I tend to give advice based on about 65 years of making 
electrical things work as advertised, or better, but always looking at 
it from the well stocked junk box view. ;-)

Scrounging is a fine endeavor, so old PSU's get tossed in a box for a 
parts warehouse.  I blew the hexfet power transistor in the motor 
control of my toy mill, 5 or 6 years ago.  Checking its part num, and 
the part num on the power bugs in the first old PSU I opened, showed the 
PSU bug was 5x the currant(good), and 3x the voltage(good) of the one 
that failed, and its gate drive capacitance was about 2x(bad), but then 
I noticed that the old one used about 2x the gate voltage, so the drive 
circuit was happy anyway.  I put it in, watched the whole thing with an 
IR thermometer for a couple hours, no hot spots anywhere on the board, 
so I covered it up and haven't looked at it since.  Bout 5 years ago, I 
even added an amp to the fuse, so now I have 2% of the former fuse 
costs.

Like Hank Williams Jr has said, a country boy can survive. :)

> Regards, Bob Devries
> Dalby, QLD, Australia
>
> On 20/06/2015 11:39 AM, Gene Heskett wrote:
> > On Friday 19 June 2015 21:27:52 Josh Harper via Coco wrote:
> >> is there anyway to hook up a power adapter that plugs into the wall
> >
> > Most such adaptyors are single voltage devices, so you would need a
> > 5 volt, amp or so, and a 12 volt, amp or so.  Sorta unhandy, so I've
> > made use of the drive conectors on an old XT supply that lives in
> > the bottom of a drive tower, to power, in my case, the whole maryann
> > including the coco3 and MPI.  But thats a lot more complex than just
> > using an old pc psu, which has all those voltages already wired to
> > its drive plugs.
> >
> >>        From: Bill Pierce via Coco <coco at maltedmedia.com>
> >>   To: coco at maltedmedia.com
> >> Cc: Bill Pierce <ooogalapasooo at aol.com>
> >>   Sent: Friday, June 19, 2015 7:23 PM
> >>   Subject: Re: [Coco] tandy 1000 ex/hx external 720k drive to use
> >> on coco
> >>
> >> The external drive he is referring to has the standard 3.5 4 pin
> >> plug (internally) and all it needs is an adapet to the larger 4 pin
> >> used on Coco 5.25 drives. The ribbon cable should be fine, it just
> >> needs a 3.2 connector pressed on.
> >>
> >> I had one of these drives and it took me about  15 mins to hook it
> >> up. You just remove all the T-1000 crap internally, then it's a
> >> standard 3.5 drive with no power supply.
> >>
> >>
> >>
> >>
> >>
> >>
> >> Bill Pierce
> >> "Charlie stole the handle, and the train it won't stop going, no
> >> way to slow down!" - Ian Anderson - Jethro Tull
> >>
> >>
> >>
> >> My Music from the Tandy/Radio Shack Color Computer 2 & 3
> >> https://sites.google.com/site/dabarnstudio/
> >> Co-Contributor, Co-Editor for CocoPedia
> >> http://www.cocopedia.com/wiki/index.php/Main_Page
> >> Global Moderator for TRS-80/Tandy Color Computer Forums
> >> http://www.tandycoco.com/forum/
> >>
> >> E-Mail: ooogalapasooo at aol.com
> >>
> >>
> >>
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: Bruce W. Calkins <brucewcalkins at charter.net>
> >> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> >> Sent: Fri, Jun 19, 2015 5:00 pm
> >> Subject: Re: [Coco] tandy 1000 ex/hx external 720k drive to use on
> >> coco
> >>
> >>
> >> The 4 pin connector (many Tandy 1000's did not have one and shunted
> >> power
> >>
> >> through the ribbon cable.) should be the standard 3.5" floppy power
> >> connector.
> >> A picture and model numbers might help identify the drive.  On
> >> the Tandy floppy
> >> drives without the 4 pin connector some of the ground lines
> >> carried the power
> >> and traces needed to be cut and power lines tapped in.
> >> Not an easy project
> >> unless you are proficient reading schematics and/or
> >> tracing PCBs.  I converted
> >> one 720k 3.5” Tandy 1000 drive about 20 years
> >> ago and would not bother doing
> >> another.  Although 1.44M 3.5” are getting
> >> hard to find nowadays.
> >>
> >> Bruce
> >> W.
> >>
> >>
> >>
> >>
> >>
> >> ----- Original Message -----
> >>
> >> From: "Josh Harper via Coco"
> >>
> >>> I have
> >>
> >> a tandy 1000 ex/hx external 720k floppy drive that I want to
> >>
> >>> convert to coco
> >>
> >> use
> >>
> >>> ive taken out the pcb that was in the case that was hooked up to
> >>> the
> >>
> >> drive
> >>
> >>> I have the ribbon cable to hook to the drive and the coco
> >>> my issue is
> >>
> >> I need to know how to get power to the drive,the power
> >>
> >>> connector is a 4 pin
> >>
> >> connector
> >>
> >>> thanks guys for all ur help
> >>>
> >>> --
> >>
> >> ---
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> >> https://www.avast.com/antivirus
> >>
> >>
> >> --
> >>
> >> Coco mailing
> >> list
> >> Coco at maltedmedia.com
> >> https://pairlist5.pair.net/mailman/listinfo/coco
> >>
> >>
> >>
> >>
> >>
> >> --
> >> Coco mailing list
> >> Coco at maltedmedia.com
> >> https://pairlist5.pair.net/mailman/listinfo/coco
> >
> > Cheers, Gene Heskett

Cheers, Gene Heskett
-- 
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