From: jgrimm@TorreyPinesCA.ncr.com (Jeffrey Grimmett 9999)
Newsgroups: comp.sys.amiga.datacomm,comp.sys.amiga.hardware
Subject: Re: Supra V32bis modems and power supplies ?
Date: 8 Oct 92 14:49:00 GMT
Organization: NCR (Torrey Pines Development Center)
Disclaimer: This posting does not neccessarily reflect the opinions of NCR.

In article <1992Oct7.123249.17321@rtsg.mot.com> king@rtsg.mot.com writes:

>>Has anyone who leaves their Supra V32bis modem running continuously had any
>>problems with overheating?  I sent a letter to Supra, but I didn't receive any
>>response.
>
>I run a BBS (no, not on the Amiga, on an MS-DOG box) with my Supra.
>Yes, the power supply gets painfully hot.  I'd read on comp.dcom.modems
>that some people were having problems with the power supply provided by
>Supra.  Apparently it doesn't provide enough current.

I agree.  Personally, I find those obnoxious power bricks to be a big pain
in the tukas.  WHY is it that Supra and others won't make the case a wee bit
bigger and put the PS inside where it belongs is beyond me!  IMO, those bricks
are a safety hazard on top of being darned inconvenient.

>While trying to diagnose some modem problems the other night I ran out
>to Radio Shark and bought a bigger supply.  The standard Supra supply
>is 600 mA, the Radio Shark supply is more than twice as big at 1300 mA.

I went a similar route, although what I ended up doing was buying a 1 amp
power transformer from a surplus house and making my own cables.  Worked fine,
but looked ugly with a capital UG.

>Note, I'm *NOT* contending that Supra ships under-powered power
>supplies.  As far as I can tell the original worked just fine.  The new
>one just gives me a little piece of mind.

hehe... well, I AM.  If it gets that hot, they're pushing the envelope and
you're asking for trouble eventually as the circuits age a bit.  Either the
transformer will eventually deliver too little current, or the modem will
load it down too much.

BTW, I might ad that the transformer is NOT very hardy.  I had to replace
mine because of a power outage.  It was connected via a filtered power
strip, and still crapped out.  Sad.

>It's hard to find a supply like this.  The output is 9V AC!  Most power
>adapters you may have around the house are 6V or 9V DC.  Nothing else I
>own uses a 9V AC power brick.  Luckily I found one at Radio Shark, and
>they only wanted about $16 or $17 for it.  From the packaging it looks
>like this is intended to be a replacement for a Nintendo supply, so if
>you've got a Nintendo machine you might be able to use that one.  CHECK
>IT FIRST!  9V DC *probably* won't hurt your modem, but do you really
>want to test it on a $300 piece of hardware?

The route I finally went was to use the built in power source of my Amiga
to provide the proper voltages direct to the modem.  The power supply in a
2000 has plenty of juice to spare.  Took a PC proto board, tapped into the
power supply from the PeeCee side, and bypassed the regulator on the Supra
(cleverly enough so that it's not obvious should I ever have to get warrantee
work, though).  The Supra's power is rock steady now, although the case is
still warm enough to cook eggs on... :-)

>-------------------------------------------------------+-----------------------
>I'm a juggler.  I have balls and I know how to         |      Steven King
>use them!                                              |   Motorola Cellular



-- 

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Jeff Grimmett [SuperBitMap BBS]        | fido!1:202/1401.0 [619-460-7290]
NCR -- Torrey Pines Development Center | Jeffrey.Grimmett@TorreyPinesCA.ncr.com
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