[sebhc] IC information

[Jack Rubin]

Bill,

If you would be willing to scan the data sheet, I'll be happy to post it to
the archive. If you can't scan it, please send me a photocopy and I'll take
care of the scanning and posting.

Thanks.

Jack

> -----Original Message-----
> From: sebhc-bounces at sebhc.org 
> [mailto:sebhc-bounces at sebhc.org] On Behalf Of William Wilkinson
> Sent: Sunday, February 27, 2005 5:18 PM
> To: sebhc at sebhc.org
> Subject: Re: [sebhc] IC information
> 
> 
> Glyn,
> 
> I just happen to have the data sheet.  According to it, the 
> extra lead on the 79MG is a control lead that determines the 
> output voltage.  On the H8, R233 and R234 sets it to -5VDC.  
> Quiescent current at 25 degrees C is typically 0.5 mA (2.5 mA 
> max).  Peak output current is 650 mA.  The 7905 is about 1 mA 
> (2 mA max) quiescent with a peak output of 2.1 amps.
> 
> If you wanted to hack the hardware, you could probably sub it 
> with the 7905.
> 
> Looking at the H8 schematic and circuit board x-ray views, 
> the only chips it appears to feed is the CPU at pin 11 and 
> the ROM (IC-204) at pin 21 through a jumper, T1-T2.  The 
> latter was probably to accommodate various types of ROMs and EPROMs.
> 
> Regards,
> Bill
> 
> 
> > [Original Message]
> > From: Glyn Firth <glynf1 at cox.net>
> > To: <sebhc at sebhc.org>
> > Date: 2/27/2005 3:23:52 PM
> > Subject: Re: [sebhc] IC information
> >
> > Thanks for the information, I checked on the 7905 and it is a three 
> > lead
> > device, the 79MGT2C is  a 4 pin IC on the cpu board. I 
> don't have data 
> > sheets on these devices, is there a trick?
> > Thanks
> > Glyn
> > ----- Original Message ----- 
> > From: "Barry Watzman" <Watzman at neo.rr.com>
> > To: <sebhc at sebhc.org>
> > Sent: Sunday, February 27, 2005 2:57 PM
> > Subject: RE: [sebhc] IC information
> >
> >
> > > You can probably get one at Radio Shack, it's just a 7905, in an
> > > appropriate
> > > case (probably TO-220, but 7905's come in lots of different case 
> > > styles)(the
> > > letters don't matter).  Very, very common and inexpensive 
> part.  Online
> > > sources:
> > >
> > > www.jameco.com
> > > www.jdr.com
> > > www.digikey.com
> > > www.meci.com
> > >
> > > [there are many others]
> > >
> > > These don't fail often, and they usually fail "open", which might 
> > > not
> > > screw
> > > up the 8080.  Look for another problem.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: sebhc-bounces at sebhc.org [mailto:sebhc-bounces at sebhc.org] On
> Behalf 
> > > Of
> > > Glyn Firth
> > > Sent: Sunday, February 27, 2005 3:40 PM
> > > To: sebhc at sebhc.org
> > > Subject: [sebhc] IC information
> > >
> > > I have just began to rejuvenate my H8 system. I have 
> discovered that 
> > > the -5volt voltage regulator on the CPU board is bad( I 
> assume the 
> > > 8080A is also
> > > cooked) The part # is 79MGT2C. I have checked some places 
> on the net 
> > > and found the IC, but most have a min order of a $100 or so.Does 
> > > anyone
> know 
> > > of
> > > a source for this IC?
> > > Thanks
> > > Glyn
> > >
> > >
> > > --
> > > Delivered by the SEBHC Mailing List
> > > 
> >
> >
> > --
> > Delivered by the SEBHC Mailing List
> 
> 
> 
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