Tech: problem with -27VDC supply on Seeburg STD3

I have a low -27VDC supply it only reads -3.0VDC.

I have checked both Q3113 and Q3120 by removing them and testing with DMM on
diode test, both tested fine. I have also taken out C3107 in case it was
shorted but still only get -3.0VDC.

I read -36VDC both sids of fuse F3102. Any ideas where the problem may be?

I also have no -13VDC but I expect this is related.

the +27VDC is fine.

TIA

Steve

--
Remove the X from the email address to email me

Disconnect the Gray and Black boxes and check voltage again. Then
reconnect one at a time and check voltages. One of the boxes might
have issues drawing down the power. Otherwise the pass transistor is
open.

Note: These are MOS devices and EXTREMELY sensitive to power so be
SURE to wait a minute or two for the power to be OFF before connecting
or disconnecting either of these boxes.

John :-#)#

On Sat, 28 Aug 2004 19:43:03 +1200, "Steve Vassiliadis"
wrote:

I have a low -27VDC supply it only reads -3.0VDC.

I have checked both Q3113 and Q3120 by removing them and testing with DMM on
diode test, both tested fine. I have also taken out C3107 in case it was
shorted but still only get -3.0VDC.

I read -36VDC both sids of fuse F3102. Any ideas where the problem may be?

I also have no -13VDC but I expect this is related.

the +27VDC is fine.

TIA

Steve

(Please post followups or tech enquires to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Hi John,

thanks for the info.

I take it the gray box is the Digital receiver Decoder and the Black box is
the Digital transmitter and pricing unit.

I disconected all 4 plugs on the above 2 units and measured -9VDC on
the -27VDC test terminal. I plugged the plugs back in 1 by 1 turning the
power off and waiting 1 minute between each plug in.

The voltage was always -9VDC, up from yesterdays 3 VDC but it seems to be
independant of draw from the gray and black boxes.

You suggest the pass transistor is open, which transistor is the pass
transistor?

Thanks

Steve


"John Robertson" wrote in message
...
Disconnect the Gray and Black boxes and check voltage again. Then
reconnect one at a time and check voltages. One of the boxes might
have issues drawing down the power. Otherwise the pass transistor is
open.

Note: These are MOS devices and EXTREMELY sensitive to power so be
SURE to wait a minute or two for the power to be OFF before connecting
or disconnecting either of these boxes.

John :-#)#

On Sat, 28 Aug 2004 19:43:03 +1200, "Steve Vassiliadis"
wrote:

I have a low -27VDC supply it only reads -3.0VDC.

I have checked both Q3113 and Q3120 by removing them and testing with DMM
on
diode test, both tested fine. I have also taken out C3107 in case it was
shorted but still only get -3.0VDC.

I read -36VDC both sids of fuse F3102. Any ideas where the problem may
be?

I also have no -13VDC but I expect this is related.

the +27VDC is fine.

TIA

Steve

(Please post followups or tech enquires to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Hi, I have an STD3 too, nice box. Does your have nice colored panels?
That paper thin coating of color sure can get dinged easy behind the
glass.

Anyway, I'm no expert like the others on here, but I had a similar
problem this spring on a control center from a USC2, low voltage at
the - test points. So I did the easy stuff first and removed and
cleaned "every" card edge connector in the DCC (brushed every card
edge with the fiberglass pen till shiny, used a modifyed safety pin to
"reform" every female connector to grip tightly) I also removed and
replaced every fuse and cleaned the fuse holder maticulously. Also
pulled all plugs on the rear of the DCC and cleaned/checked. Also did
the black and grey box connectors too. And some by the record rack.
Wheooo...

After all that, the voltages came back to normal! I suspect in my
case it was one of the fuse holders, but not sure. My box had sit for
a number of years in a ware house, so bad connections seem logical.

Let us know if this helps. If you need to go further, it will be good
learning for me too!

Yours, Joe

Hi Joe,

My coloured panels are in "average" condition I am considering reproducing
them by having a printer digitally print the design onto adhesive backed
mylar and then sticking the mylar to a lexan sheet. Must say it is unlikely
to happen before the end of the year though. First thing is to get the box
running.

I doubt that my voltage problem is a connector issue as I have the
unregulated voltage fine but it I get no regulated voltage including when I
measure right on the circuit board.

Steve

"Joe" wrote in message
om...
Hi, I have an STD3 too, nice box. Does your have nice colored panels?
That paper thin coating of color sure can get dinged easy behind the
glass.

Anyway, I'm no expert like the others on here, but I had a similar
problem this spring on a control center from a USC2, low voltage at
the - test points. So I did the easy stuff first and removed and
cleaned "every" card edge connector in the DCC (brushed every card
edge with the fiberglass pen till shiny, used a modifyed safety pin to
"reform" every female connector to grip tightly) I also removed and
replaced every fuse and cleaned the fuse holder maticulously. Also
pulled all plugs on the rear of the DCC and cleaned/checked. Also did
the black and grey box connectors too. And some by the record rack.
Wheooo...

After all that, the voltages came back to normal! I suspect in my
case it was one of the fuse holders, but not sure. My box had sit for
a number of years in a ware house, so bad connections seem logical.

Let us know if this helps. If you need to go further, it will be good
learning for me too!

Yours, Joe

My Olympian did the same thing to the point that the coin gear did not
work and it was slipping selections like crazy

it was the DC power supply board its under the buffer board inside the DCC
check all solder joints and make sure the edge connections are clean it
should come back to life or you have a bad cap on that board or a bad wire
shorting in the dcc or the machine itself.

Jim W
"Steve Vassiliadis" wrote in message
...
Hi Joe,

My coloured panels are in "average" condition I am considering reproducing
them by having a printer digitally print the design onto adhesive backed
mylar and then sticking the mylar to a lexan sheet. Must say it is
unlikely
to happen before the end of the year though. First thing is to get the box
running.

I doubt that my voltage problem is a connector issue as I have the
unregulated voltage fine but it I get no regulated voltage including when
I
measure right on the circuit board.

Steve

"Joe" wrote in message
om...
Hi, I have an STD3 too, nice box. Does your have nice colored panels?
That paper thin coating of color sure can get dinged easy behind the
glass.

Anyway, I'm no expert like the others on here, but I had a similar
problem this spring on a control center from a USC2, low voltage at
the - test points. So I did the easy stuff first and removed and
cleaned "every" card edge connector in the DCC (brushed every card
edge with the fiberglass pen till shiny, used a modifyed safety pin to
"reform" every female connector to grip tightly) I also removed and
replaced every fuse and cleaned the fuse holder maticulously. Also
pulled all plugs on the rear of the DCC and cleaned/checked. Also did
the black and grey box connectors too. And some by the record rack.
Wheooo...

After all that, the voltages came back to normal! I suspect in my
case it was one of the fuse holders, but not sure. My box had sit for
a number of years in a ware house, so bad connections seem logical.

Let us know if this helps. If you need to go further, it will be good
learning for me too!

Yours, Joe

Yes, I recommend re-capping the power supply before attempting other
repairs. Those electrolytic capacitors are getting rather old...

John :-#)#

On Mon, 30 Aug 2004 03:42:26 GMT, "Happy Seeburg Owner"
wrote:

My Olympian did the same thing to the point that the coin gear did not
work and it was slipping selections like crazy

it was the DC power supply board its under the buffer board inside the DCC
check all solder joints and make sure the edge connections are clean it
should come back to life or you have a bad cap on that board or a bad wire
shorting in the dcc or the machine itself.

Jim W
"Steve Vassiliadis" wrote in message
...
Hi Joe,

My coloured panels are in "average" condition I am considering reproducing
them by having a printer digitally print the design onto adhesive backed
mylar and then sticking the mylar to a lexan sheet. Must say it is
unlikely
to happen before the end of the year though. First thing is to get the box
running.

I doubt that my voltage problem is a connector issue as I have the
unregulated voltage fine but it I get no regulated voltage including when
I
measure right on the circuit board.

Steve

"Joe" wrote in message
om...
Hi, I have an STD3 too, nice box. Does your have nice colored panels?
That paper thin coating of color sure can get dinged easy behind the
glass.

Anyway, I'm no expert like the others on here, but I had a similar
problem this spring on a control center from a USC2, low voltage at
the - test points. So I did the easy stuff first and removed and
cleaned "every" card edge connector in the DCC (brushed every card
edge with the fiberglass pen till shiny, used a modifyed safety pin to
"reform" every female connector to grip tightly) I also removed and
replaced every fuse and cleaned the fuse holder maticulously. Also
pulled all plugs on the rear of the DCC and cleaned/checked. Also did
the black and grey box connectors too. And some by the record rack.
Wheooo...

After all that, the voltages came back to normal! I suspect in my
case it was one of the fuse holders, but not sure. My box had sit for
a number of years in a ware house, so bad connections seem logical.

Let us know if this helps. If you need to go further, it will be good
learning for me too!

Yours, Joe




(Please post followups or tech enquires to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Steve; I have an email friend in England who also has a Sunstar and
has had a printer make him new colored panels. They were expensive
for a one-off deal, but he has mentioned he thinks the printer may
still have the pattern? to make more. Let me know if we should check
further.

My panels are "okay", a few small chips and scratch marks, but perfect
ones would really make the box stand out. A nice visual impression is
important on these "non visible mech" boxes, I think. However, I have
yet to hear any visible mech boxes beat the sound quality of these
70's Seeburgs. Course, I haven't listened to all that many old ones,
but a few.

Joe