Re: Where to start on Missile Command PCB repair

Ok I found the crystals and I will have them tomorrow, I can work on the
sockets tonight at least!

On Thu, Oct 31, 2013 at 9:19 AM, Grant Thienemann <
grant.thienemann@gmail.com> wrote:

> Hey Matt,
>
> Thank you for the information! I actually have two missile commands I'm
> trying to get working at the moment, my stand up which I never got working
> and my cockpit which I picked up this weekend. I want to get both working,
> and in reality I would like to get at least 3 board sets working because I
> have an original Super Missile Attack add-on daughter board that I would
> like to put in a machine as well! Here is what I've figured out so far
> from yesterday afternoon, I didn't get to work on it last night because I
> was watching my kids!
>
> [image: Inline image 2]
>
> 1st. I had checked the voltage at the ARII not at the Missile Command PCB.
> The voltages I had scene at the PCB were -5.1 volts, +11.75 volts,
> and +4.68 volts. I adjusted the +5 volts slowly with my fluke connected to
> the test loops on the pcb until the +5 read +5.02, the other two voltages
> stayed the same. I re-tested 4 of my 6 PCBs and with basically the same
> result, nothing on screen, though two boards cause the coin counter to just
> go berzerk.
>
> 2nd. I have the all the new sockets to replace all the socket-ed chips on
> the PCBs with new sockets. I'm replaced the ram sockets on my best looking
> PCB and in taking all the ram out I did lift one trace but I was able to
> fix it with trace wire on the solder side of the PCB. I have a Hakko 808
> desolder gun, I find people either love it or hate it, I love mine, so
> taking the sockets off the PCB is too difficult, I just have to be
> carefully of lifting a trace wire on the parts side. Also I have a Weller
> soldering station as well, analog not digital that works well. I'll work on
> replacing the 40pin 6502 socket tonight and the 6, I think its 6, sockets
> for either the EPROMs or PROMs that go on the PCB.
>
> 3rd. As of yet I haven't been able to get any of my PCBs to do anything in
> test mode, however if what you are saying about the sockets is correct,
> then that could be the problem. I noticed with one PCB I plugged it in, put
> in test mode, nothing and when I went to check the voltage on the PCB the
> 6502 wasn't even installed on the PCB. So I think one major problem with
> all my PCBs are the sockets.
>
> 4th. I haven't looked at the crystal yet, and I'm not even sure where it's
> located, I'm going to go look at the schematics now to see where on the PCB
> it's located. I know I don't have any spares, where can I pick those up at?
> Does anyone have a part number to digikey or does Radio shack carry them?
>
> 5th. I know you can replace the 4116 with 4164 ram however from what I've
> found online you need to change jumpers OR the wiring harness for the PCB,
> are there jumper settings for the ram on the PCB?
>
> 6th. I have heard about the 2708 and 2716 EPROMs however I haven't been
> able to find any information those far on how the jumpers should be set on
> the PCB, do you have a link to that information somewhere?
>
> Thanks
> Grant
>
>
> On Thu, Oct 31, 2013 at 12:19 AM, Matt J. McCullar <mccullar@flash.net>
> wrote:
> > Howdy, Grant! I've worked on several "Missile Command" boards, and
> here's
> > what I've learned...
> >
> > * Replace all the sockets. If yours are original, they are over 30 years
> > old now and their contacts are just as corroded as the pins on the chips.
> > Yes, it takes practice to desolder all those things effectively, but new
> > sockets will eliminate a great many headaches. (Replace the socket
> > underneath the 6502 processor, too.) [You may find some ripped-up
> > printed-circuit traces underneath these sockets; some people pry out
> those
> > chips without being careful, so you may have even more soldering to do.]
> >
> > * Is the crystal still there? The main clock is generated from a 10.000
> MHz
> > crystal, and all too often when I see a "Missile Command" board, that
> > crystal is just flat-out missing. Even if it's still there, it should be
> > solid in place and not easy to move around with your finger.
> >
> > * I like to replace all of those old 4116 RAMs with newer 4164 RAMs, that
> > have been "tricked out" to resemble 4116's. You can find information on
> how
> > to do this on the Internet; it's not that difficult. The 4164 chips are
> > newer, use only +5 volts (instead of several bus voltages as the 4116s
> do),
> > and may be much easier to find on the market these days.
> >
> > * A real curve ball: Atari designed the motherboard so that it could
> accept
> > two different kinds of EPROMs: 2708s or 2716s. There are lots of solder
> > pads (jumpers) next to the ROM sockets that tell the hardware which chips
> > are being used. You must look at these very carefully; a pad may be cut
> or
> > it may be intact (or resoldered). 2708 EPROMs use several bus voltages
> and
> > those pads must be configured for such; 2716 EPROMs hold twice as much
> > memory and use only +5 volts, but again those solder pads must be
> configured
> > for them. If the wrong type of EPROM gets plugged into a socket that
> > doesn't have those pads set correctly, it may destroy that EPROM. (I
> like
> > to "strap" the boards for 2716s, as they are far easier to obtain and
> work
> > with. If you have a "Missile Command" board that has EPROMs in every
> single
> > socket, they are probably 2708s; if only half the sockets are populated,
> the
> > chips are probably 2716s. But someone else in the past may have swapped
> > chips around without knowing the difference.) [If you use just 2716s,
> you
> > only have to replace half of the sockets!]
> >
> > * Take lots of careful notes. Be sure the correct EPROMs/ROMs go in the
> > correct sockets.
> >
> > Defend cities!
> >
> > Matt J. McCullar
> >
> >
> > -----Original Message-----
> > From: owner-rasterlist@vectorlist.org
> > [mailto:owner-rasterlist@vectorlist.org]On Behalf Of Grant Thienemann
> > Sent: Wednesday, October 30, 2013 6:32 AM
> > To: rasterlist@vectorlist.org
> > Subject: RASTER: Where to start on Missile Command PCB repair
> >
> >
> > Hey Guys,
> >
> > I've got a stack of Missile Command PCBs that don't work and I need
> > some guidance on where to start. Here is what I have done with my
> > first PCB.
> >
> > Checked the PCB in test mode, doesn't nothing, just an audible hum
> > Felt all the chips to see if any are hot, none were warm to the touch
> > Replaced all the 4116 ram with sockets and cleaned the ram legs, still
> > nothing.
> >
> > I have the following equipment at my disposal though honestly, I don't
> > know how to use some of it.
> >
> > HP Logic comparator
> > HP 5004a <-- haven't used them yet
> > Atari Catbox <-- haven't figured out how to use it correctly yet
> > Fluke 9010a but no 6502 pod :-(
> > Logic Probe <-- haven't used it yet
> >
> > Any information would be fantastic!
> >
> > Thanks
> > Grant
> >
> ---------------------------------------------------------------------------
> > ** Unsubscribe, subscribe, or view the archives at
> http://www.vectorlist.org
> > ** Please direct other questions, comments, or problems to
> chris@westnet.com
> >
> >
> ---------------------------------------------------------------------------
> > ** Unsubscribe, subscribe, or view the archives at
> http://www.vectorlist.org
> > ** Please direct other questions, comments, or problems to
> chris@westnet.com
>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Thu Oct 31 11:01:37 2013