Re: Tron progress made (yay)

I believe it's ROM error "D6" - not "06".

That would indicate the chip located at D6, and the error is caused by
either the LS138 decoder (from memory), a bad socket/connection, or a bad
EPROM. If you're getting multiple ROM errors, it could also be the octal
buffer ahead of the EPROM bank.

I went through this exact issue earlier this summer, and cleaned
the EPROM contacts with a pencil eraser, replaced the EPROM socket, and
decoder only to eventually figure out that the EPROM was suffering from
bit-rot.

The EPROM checksummed right, and compared right, board voltage(s) were
good (5.07Vdc at the chip) but just was not reading up to par on the
board. I programmed a new one, and it's worked fine ever since. First
time for everything I guess.

On replacing sockets - it's relatively easy if you take the right
approach. I (GENTLY!) pry the plastic carrier away from the pins leaving
the pins alone in the board. If you use a small screwdriver, for the love
of Pete don't pry against neighboring chips, and if/when prying against
the board, have something between the tool and the board (electrical tape,
a small piece of cereal box cardboard, whatever) to protect the traces
from damage. In the case of a non-socketed IC, cut the pins right
next to the package body with a flush-cutter, or Dremel, and the rest of
the procedure is the same.

Then, just heat each solder joint and pull the pins out with a tweezers.
Clean the holes out with solder wick or a solder sucker, and drop a new
socket in place.

I usually clean the area up with a Q-Tip soaked in Acetone to get the
gunk off before I solder a new component in place - I'm a little picky
that way :)

Brad

On Mon, 29 Oct 2007, EvilJim wrote:

> Alright, after rebuilding some buss bars, replacing the electrolytics and
> fixing one previous (and really ugly) repair, we have life out of the Tron.
> Hooray! Power seems to be good (and clean) to the cabinet and the logic. On
> power-up, while I didn't get the perfect attract mode response that would
> negate the need for this posting, I did get an image on the monitor.
>
> That image is: ROM error 06
>
> While I do have the original Tron manual, there is no info in it concerning
> error codes. Therefore my question would be, does this translate to some
> particular error or is this just telling me that something is wrong with the
> 6th ROM on the board?
>
> I tend to expect it means the latter, and if so, is this the point where I
> replace all the sockets on the boards? A daunting prospect to say the least.
> I think I can do it, I'm just concerned about how much trouble I might cause,
> mostly getting the old ones off. (Heat issues, lifting traces and the like.)
> If I am looking at a re/programming issue, while I believe I do have access
> to a burner at the lab, I have never used one. My main concern there is
> where I actually obtain a known good copy of the image to burn to the chip.
>
> I got to this point when it was time for me to leave the lab, so I have been
> unable to do things like logic probe the inputs/outputs on ROM 6, or
> pull/seat all the chips again.
>
> Thanks for all the help so far, and TIA for the help I hope follows this
> posting. =)
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Received on Mon Oct 29 19:16:37 2007