reverse-engineering power

From: jpero_at_mail.cgo.wave.ca <(jpero_at_mail.cgo.wave.ca)>
Date: Sun May 17 17:45:01 1998

Doug,

> On Sun, 17 May 1998 jpero_at_mail.cgo.wave.ca wrote:
>
> variable regulated supply (this is silicon valley, after all), but they
> were all around $300, so I went home without.

Ditch that thing, these warts with switches can't carry more than few
mA's for serious work and they're junk anyway. For decent DIY
homemade adjustable basic power supply by a pot to a voltage LM317
regulator (with heatsink attached) and few large caps attached to a
rectified DC rated about 1~1.5 Amps 24VAC transformer. Should not
cost more than $40 and many electronic supplier and component stores
should carry a electronic kit that you can build yourself instead of
this piecemeal one. Another circuit added to this basic using another
LM317 in current mode limiting level fixed by a pot. Look into your
local phone book and find a store that is a walk in store that allows
you to browse at electronic components and carry tools (many should
carry decent tools if found) and lot of kit stuff to put together.

For wall warts, I use fixed DC types only for few things as I don't
like the swtichable types as I had them die one too many before.
And kit form power supplies are much better than this wart crap.

Oh, there are several types of LM317's with different max current
ratings: 500mA, 1A, 1.5A and 3A, up.

 
> OK, I took off the board to get to this black box labeled ERG INC, E1015,
> 9210E, but the output seems to go only to the LCD.
That one is not it. that's lamp inverter PSU to light both
fluorcsencent and some to power the LCD for operation.
That LCD will not come alive without bios as video is under control
by that one bios. Often that chip is combined with system bios and
the video bios in one chip. Look for naked transformers or three
with lot of small power transistors and few big caps around it is
your real power module and these are very close to that power input
jack.



> > 3.3V based portables started to appear after Intel and AMD introduced
> > their 3.3v chips and chipsets became common after '91 or so.
> > That real appearance takes place about a year after this and totally
> > converted over to all 3.3V logic well after dx4 portables became
> > common.
>
> This is from early '93, and has a Cyrix 486SLCe/V25-MP.
>
Fair chance that you have a mixed 5V and 3.3V chips.

This is 3.3V chip and real dog even at 25mhz with 1K L1 cache on,
it's on par with cached 386dx 25. I have one on a cheapo 486SLCe 5V
33 version. No better than a slow cached 386dx 33. Real IBM
486SLC2/50 blew everything away even 486sx2 40! That's in a 700C.

> Man, you do have a sharp eye; there appears to be an empty ROM socket on
> the bottom of the board (but I'm hoping against hope that they integrated
> Flash into one of the big chips).

Taking a bow at this praise. :) Btw pix does matter.

Well, supposed to find a 32pin SOJ small profile retangular chip that
could be a bios or a flash chip usually iwth a sticker over it.

>
> > Did you have that 32pin SOJ socket empty? That is might be the
> > socket for that bios oh, what a big bummer!
> >

For short term, ID who's who video chipsets by that logo make and the
motherboard chipsets as well as their numbers off them and try to
boot with a subbed bios and see how it go in very basic operation?

> There's no way you could have seen the Areal MD2060. Do you have any
> picks for the stock market tomorrow?

I can't afford or own stock I'm still on "welfare". :( That will
change after I get real and get done with education, land a good job.

About that hd,
I'm not kidding, I have a dead Areal MD2060 too and this is just
stock 60mb 44pin IDE out of a 386sx 20 small laptop, and you can
change that hd for anything (used or new) up to 8gig with driver
software if that bios works. :) I had the 386 owner replace that hd
as it was making new bad sectors every time I scan that hd for a NOS
200mb seagate G series about couple of years ago at good price from a
known reseller out of computer shopper.

>
> -- Doug
>
Jason D.
email: jpero_at_cgo.wave.ca
Pero, Jason D.
Received on Sun May 17 1998 - 17:45:01 BST