[Jukebox-list] a question, a comment, & a tip.

Jay Hennigan jay at west.net
Mon Apr 2 12:01:39 PDT 2001


On Sun, 1 Apr 2001, BSA King wrote:

> The q:
>
> The culprit is my Seeburg FireStar. A select problem - was working. Now when
> I press the keys, it does not start to scan and pickup. If I click the mech
> switch, it will go & work fine.
>
> Dr. J suggested  check the scan board. There's a SCR (Silicon Controlled
> Rectifier), similar to a triac, that pulses the scan control solenoid. The
> solenoid can also be pulsed with the switch I mentioned.
>
> Thing I now noticed today is that it selects perfectly if I push the buttons
> while it is either playing or scanning, but not from a stop position. That's
> what threw me at first - thought it was fixed, then it wasn't. There is a
> pattern to it.

That one's newer than most I've dealt with, but there are two things that
happen when you make a selection.  One is to set a flag to trip the mech to
play that record when it scans by, and the other is to cause the mechanism
to scan (or remain scanning).  With pinbanks, the scan starting was done by
means of a contact washer grounding a contact whenever one or more pins was
selected.  With Tormats, a two-step rachet was set that decremented once per
scan.  so, it sounds as if the "More selections may remain" function is not
happy.  You'll likely need a manual to go further.

> The (well, potential) tip:
>
> While starting with basics, I took the keypad out of the FireStar and
> noticed the contacts on the board were not in the best of shape. Sort of
> surprised that the copper traces appeared of different thickness, scratched,
> etc.  I had tried cleaning them, but they still had that flakey feel in
> terms of contact. What I did was recoat them all in solder to thicken up the
> edges a bit.
>
> I clamped the pieces so I had a 'third hand', then coated the traces with
> solder. Nice & clean and even & not too much heat - don't want to lift
> thoses traces off the board. Then I used solder wick about the same size as
> each trace. Heated up the braid on the pad connector until solder flowed
> into the braid, and slowly pulled the braid towards me (towards the insert
> edge of the trace). This left a really smooth solder built up trace which I
> then polished and cleaned.
>
> Now that board has a real nice factory snug feel to it, instead of being a
> sloppy fit. My problems still exist (see q: above), but at least I am now
> pretty sure it is not that part causing it.

This is likely to cause many problems down the road.  Solder-plated contact
surfaces tend to oxidize and cause problems.  Generally, contacts are tin
plated or gold plated, with gold being preferred and more expensive.  If
this is an edge connector, I'd recommend either attempting to tighten up
the mating contacts or replace the mating connector.  I would not recommend
solder-plating or "tinning" contact areas with solder.

-- 
Jay Hennigan  -  Network Administration  -  jay at west.net
NetLojix Communications, Inc.  NASDAQ: NETX  -  http://www.netlojix.com/
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