Re: BattleZone probs....

My experience with Midway power supply boards is
that the power transistor looses gain which runs more
current through the LM305 and, eventually, blows the
.25 amp fuse. Every one of these I've worked on
worked fine after replacing the power transistor (which
I never had, so I just swapped it with the other one
on the heatsink).

Mark Shostak wrote:

> >I've bought a complete set of replacement sockets for the ROMs which I intend
> >to install shortly (even though the existing ones seem to be in excellent
> >condition). I was toying with the idea of using turned pin sockets however, but
> >considering the extra cost I'd have to be convinced that there would be an
> >appreciable reliability increase....I recall having problems some years ago
> >when using turned pin sockets in prototype equipment.
>
> It all depends on what you value more, your time or your money. I always try
> to use machine pin sockets. A few extra pennies for a good socket can save
> you HOURS looking for the solder splash UNDER the socket, or the bent finger,
> or whatever the defect de jour may be. You couldn't pay me to use the cheap
> (non-machine pin) sockets, it's just not worth it.
>
> <2N3055s>
> >They're a dime a dozen.
>
> >Yes, I got the wrong end of the stick. Apparently it's the LM-305 which is
> >supposed to be unavailable....
>
> If they are unavailable, I'd just buy another aud/reg board. They're cheap and
> the LM305 isn't handling much current, so it's likely to be good. Also, you
> can use one of the Midway Space Invaders power supplies. They also used
> the LM305 and sport a 2N3055. Although, at this point, there may be more
> of those IN the "pond", than on either side of it.
>
> If you can't find a regulator board over there, you could have someone selling
> one over here, pull the LM305 and trash the rest. The exchange rate will work
> in your favor for this type of operation.
>
> -Mark
>
> >Good luck (you'll need it)!
>
> >I know, I've been wrestling with this machine for nearly 18 months on and off
> >now (though granted I'd not touched it for 12 months until the other day). So
> >far I've fixed some 6 or 7 faults....though three of those were bad RAM chips
> >which may not have been....
>
> P.S. Don't forget to resolder your math box connectors. :)
>
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Received on Tue Jan 19 04:24:56 1999