Re: New Irobot owner

On Sun, 23 Apr 2000, Jess Askey wrote:

> If your power supplies are all okay, then there are multiple problems that could
> be happening with the boardset.

>From what I rememeber reading, these supplies are prone to failure...I
have 3 and all are dead. The schematics for the PS are up on game archive
(thanks to Jess) so starting there is the place to go. I'd get the game
up and running with the new switching PS, then work on the Atari one on a
bench.

Another big problem with the Atari one is the weight. It has that massive
heat sink and inductors that weigh a ton...mounting this veritcally puts a
lot of stress on those guys and could lead to problems...

That switching PS provides all the functions of an isolation transformer,
degaussing circuitry (remember, these games used that garbage DISCO
Trashifone (Amplifone) monitor, audio amplification, and voltage
generation/regulation (of course). My most recent hack job was a pain to
do as the cabinet has very limited space. However, I have another I am
doing for myself and I've learned a lot about it...I'm using a new
swithcing PS and an external audio amp (as per Clay Cowgill's advice).

Oh, getting back to the monitor...remember, most of those DISCO monitors
are crap as well...you might want to concider switching it out for an
easier to repair WG or Electrohome.

>First, see if the watchdog is barking, if so,

What does it mean if a watchdog is stuck high?

> then check the main CPU and associated chips (verify all ROM's and other
> socketed chips first). The big bank of video RAM on the video board was known to
> have big failure problems. Im not sure if that would keep the board from booting
> however. Unfortunately, Atari didn't socket any of these Mostek RAM's, you will
> have to pull them all manually and this time, maybe add sockets. The Actual RAM
> (4164's I think) are a dime a dozen on many old 80286 motherboards.

4164s are dirt cheap from Jameco too! I fixed my first I, Robot board
this weekend for a friend and am currently fixing mine right now! (I have
a reset problem...it is forced low...hopefully it's just a problem in
the power-on reset circuit).

>
> Also, the self test errors that the game displays are wrong in certin
> circumstances. I would do a deja search in RGVAC for more info on this as I
> can't remember which two messages are swapped.
>

Didn't know about this...Deja News only goes back to 1999 now though :(

> I don't think that the power supplies are all that bad if yours is initially
> working. I think the big problem with them was that it was in the early years of
> a switching power supply (if not the first) contained in an arcade game. Most
> techs never got down into the theory of fixing them since later they were so
> cheap that you just threw away the old one and put in another peter chou.
> Im sure that the power supply has some weaknesses in it's age but given that you
> do an inital re-cap, everything should be fine.

Again, I had read these things were crap...also, you're going to want to
tie some of the supply voltages directly to the board (there are TP lugs
that allow you to easily do this). I, Robot draws a lot of current and
the tiny edge supply paths are inadequate (i.e. you see a lot of burned up
edge connectors). They form a bottleneck almost...if I am not mistaken,
this acts like a resistor, gets hot, and burns.

>
> I wish I had an I,Robot too. :-( I only have the hall effect joystick, so far!
> :-0
>

Great game! Too bad there weren't more...maybe you could hack your HE
joystick into your PC and play John Manfreda's emulator :)! He did an
awesome job...incredible speen on even "low-end" machines like my P233.

I wish I could get more info on that ICY II video IC (custom Atari chip).
Was that used on any other games?

Ed

> jess
>
> Steven Zeuner wrote:
> >
> > Hi folks, I Robot #296 owner here. :)
> >
> > The game is all original and has the large switching supply inside. There
> > is also a modern switching supply hacked into the old switching supply. I
> > like my machines as original as possible.
> >
> > I've heard the older switching supply is junk and unrepairable, any truth to
> > this?
> >
> > Is there a FAQ available to help me find out the cause of the machine not
> > coming up?
> >
> > Thanks,
> > Steve
> >
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Received on Mon Apr 24 08:41:46 2000