Golden tee fore green board no boot black screen

[mclovin]

Hello all, I have another dead GT green board I would like to try and Resurrect. This one is just black screen, will not boot. The board has two green lights like normal. I have a working board and another board for parts so I tried all the obvious things I could think of.. Power supply is good, monitor is good, swapped video cards, boot EPROMs, touched up on some solder, no obvious signs of spills or damages. Does anyone have any suggestions on where I can start? once again I have a parts board I can rob parts from. 

[ed12]

man what a trip
had to go to debain to log in ??
anyhow,what is the red led doing :i/o: with or without a harddrive ?

ed

[mclovin]

I can double check again, but I am pretty sure there is no activity at red. I will double check, also the green status is not flashing just solid, sometimes dim sometimes bright.

[ed12]

green=status lights >buss working<
red=ide seeking
1 of the green's stuck ? on/off and NOT flashing = buss is getting bogged down
list me the led # and i will point u to the problem

ed

[mclovin]

D5A status 2 blinking constant pattern. D20 status 1 solid green very dim light...no ide activity red led nothing, just a quick flash when first powered up, hard drive is connected.

[ed12]

D20=main cpu route
chk's as follows

osc. >scope<
u2 chk for toggle of data line's
also chk for coureted pin's >black instead of tin<
u15 chk for data and adress >is it an egale rom?,if so sub it for another rom<
also a latch up in u20,23,24 will cause that.
side note on this is/was a shorted harddrive/sd-card

ed

[mclovin]

Ok I will check everything you suggested. I don't know the history but I do believe the hard drive may have been shot originally, could have been shorted. Regarding u 15 it had a known good 1.06, then I just swapped it with a known good eagle 2.04 and oddly the D20 light is much brighter now but has a very slight quick blink to it.

[mclovin]

U2 looks ok to the eye, swapped u20, u23 & u24 and still same problem.

[ed12]

2.04 is older u want 2.09

the u's u talked about are on the ide bus >chk these for data toggle<
best is a logic prob,but a dvm will do the job,just alot slower,eyeing and swapping is not really fair enough,to the extent
i want to know what the bus is doing.?,also chk u15's socket they were and are garbage at best

ed

[mclovin]

Thanks for the help Ed, but this is over my head, I am not experienced enough at this to understand. Looks like this one will have me beat. I was hoping I could just swap things.

[ed12]

just hold tight
u got a dvm? or a electronics wholesale house around u ?
if so the cheapie logic prob's are olny 30.00 cdn max
well worth the time and money.
if u can u use a dvm i can walk u through what i am looking for.

ed

[mclovin]

If a dvm is digital volt meter than yes I Have a pretty good one.

[ed12]

great
and yes dvm = that
have to dig out the  list

ed

[mclovin]

Ok let me know where to go from here?

[ed12]

with your dvm in it's lowest dc range..ie:2/20/200 vdc or 5/50/500 vdc,so lowest range is >2vdc< or >5vdc<,
take your black or negative wire of your meter to ground.
now make sure it is a good ground.
next with your postive + probe,what you will do is to check each singal pin on the eprom.
so adress and data line,s,the propuse of this is to see if they are :clocking: :ie: on/off.
with a dvm this will happen very fast,so u need to keep an eye on not olny the meter but where u are probing.
now go to google and download the pdf on your eprom so u can tell which line's are which,
also make sure that YOUR DVM AUTO-RANGING is set to OFF.most important it is OFF.
this can be done on 90% of the chip's expect about 4..
cheap man's logic prob

ed

[mclovin]

ok here is what I found. Some of the values jumped around a bit, and some were a very slight negative voltage. THe values also changed after a minute or so of power up, so i tried to give values right after powering up. I am not sure if this will mean anything to you or not? I do not understand schematics.


Pin 1 -.02 volts       
2 -.02v
3 -.02v
4 2.85v
5 .02v
6 2.5v
7 .5v
8 2.0v
9 1.5v
10 2.0v
11 2.0v
12 2.0v
13 3.0v
14 1.4v
15 1.5v
16 0v

17 1.7v
18 1.5v
19 2.1v
20 1.6v
21 1..5v
22 .970v
23 .03v
24 .965v
25 .03v
26 3.2v
27 .35v
28 .02v
29 .015v
30 -.013
31 -.014
32 5.0

[ed12]

i am going to refer it to the eprom
give me 30 mins

ed

[ed12]

holy ---steaming pile of meadow muffin---
that is 1 messed up eprom

pin1-pin12 are the first bank of adress lines
pin31-25 inculding pin #23 is the second bank

there is your problem
i know u siad u swaped back the eprom
but once u replaced the socket,u might need to reprogram the PROPER EGALE 2.09 into it

ed

[mclovin]

The thing Is this EPROM works in another board just fine. I don't have a 2.09, but I ordered a programmer on eBay over a week ago so I hope it is here soon.

[ed12]

did u grab the .txt i up-loaded ?

ed

[mclovin]

You bet. 

[ed12]

i will admit
it dose jump alot
but the gist of it is there...
edit away and share or edit away and save....
it is work in motion

and thk-u   

ed

[ed12]

thk-u @ for re-pointing me onto a file i did forget to up-load.

name PONYPROG
file ussage
enable a person to lift 2 pin's on any 93-xx chip or other eeprom
and onboard real time read/re-program the same said chip
it is done through a real serial port,i have never tried it on a usb to serial so i do not know 

the way is simple
ground/sco/sc1

the file has it's own setup file in it
just .exe. it and go
as ALWAY'S SCAN FOR TROUBLE

i will get the hook-up's and add them as a edit when i get a chance

ed