Star Tech Journal

Leland Coin Input
Ckt Clarification
Douglas E. Totty
The Leland Corporation
El Cajon, California
This note is to clarify some misinformation delivered
in the article entitled "Leland Coin Input Circuit" by
James Beck which appears on page 15 of the Janu-
ary, 1989 issue of STAR*1ECH Joumal.
Seeburg CD Inter-
Dlittent Proble111s
Chuck Green
Snodgrass Sales
Terra Haute, Indiana
PROBLEMS
Well, after much research, and some help from
Seeburg, I have finally solved the problem of songs
being cut off, songs not playing and credit problems
on the Seeburg CD jukebox.
CLARIFYING DESCRIPTION
We do rwt use the /NMI input of the master Z80
processor as the means by which we count coins and
generate credits. An /NMI is only generated with the
first depression of the service switch or the first coin
drop through either of the two coin mechs. All subse-
quent /NMI's fail to reach the master processor
because Ul 15 is never reset.
ACTUAL CAUSE
~Coins are read by polling an input port (25) times
ivery VBLANKG and reading a specific bit. When a
coin switch gets stuck closed, the program goes into
a continuous polling loop. This is the official reason
for a game freeze-up Oust to keep the record straight).
·.-:-::::::::::;:::::::::::::::::::::::::::::::;:::::::::::::::::;:::::::::•:::::::::;:::::::::::::::::::::;:::::::::::::::::::;:::::::::::::::::::::;:;:;:;:;:;:::::::;:;:;:;:;:;:;:;:;:::::::::::::::::::::::;:;:;:;:;:;:;:;:;:;:;:;:::;:::;:;::::,:-,•.
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REMOTES
First of all, get rid of the wireless remote. They are
junk. In most locations you have got neon signs that
create lots of interference. Especially the ones that
flicker. The range of the remote is VERY short. In
some locations it would not work across the room!
Wired remotes are available from Seeburg.
PROGRAM UPDATE
Program update R3/R5, U3/U5 solves the problem of
songs being cut off. That bug has been alive for years.
INTERMITTENT$
To solve the intermittent problems: credits, the songs
being cut off and songs not being played: Take your
updated program and read it into a Epromreader and
copy it to a GOOD Eprom. The brand of Eproms that
Seeburg uses we had problems with -BUT the pro-
gram was just fine. We had an L5 that was cutting
every song off. So we replaced it with another L5 and
it worked fine. Took the suspect L5 and put it in a good
box and it cut every song off. I then read the good L5
and the bad L5 and the programs were the same!
So I copied the L5 into known good Eproms and
updated our boxes. That cured a lot of problems. The
difference between R5 & U5 is that a minor bug was
fixed on the playmaker stimulator. I have used R5 on
a box (that is played a lot) for a month now and so far,
no errors. (Cross my fingers!) Be sure that when you
update the box that you check the pricing. R5 factory
default is 3 for a dollar but can be set to 5 for a dollar.