SILVERBALL sound problem?

[Ace]

Hi Guys,
I have an old Bally silverballmania at home and use it to check and find faults on my boards on other machines.
I had a problem with my other bally machine on the solenoid driver/voltage regulator board there was only 1 volt at the voltage regutator.(TP1 AND TP3)
So i had a spare regulator 5v and changed it over but i only soldered the 2 wires ,no heat sink,just to see if this was the problem.
but idoit me didnt realize that you have to put one of the bolts throw the unit and the heat sink to make a contact on the other side of the board.
i have fix the problem on the solenoid board but i have no sound now. There is amp sound coming from speaker but not tunes.U1 chip on sound board gets hot.
Have i blown some thing on the MPU or Sound board?
if any one has advice on were i should start?
thanks for you help

Ace.

[Strangeways]

I don't think so as the section of the circuit you were fixing is for the HV on the displays.

Coincidence. Check the connectors for dry joints.

[illawarra_steelers]

No idea on the repair.....but.......

ANOTHER KISS fan 

[Ace]

OK. I have check all dry joints resolder them. still the same.
check all TP on all boards and all read good.
then i swap the solenoid board with my working playboy machine and swap the MPU board.
still the same. have i elemanated the mpu and sol board from being the problem?
When you press the small red switch on the sound board it makes a low tone noise.
the  U1 chip on the sound board get really hot you cant touch it, is that normal?
What should i do next??

thanks for the help!!

Ace.

[Strangeways]

OK. I have check all dry joints resolder them. still the same.
check all TP on all boards and all read good.
then i swap the solenoid board with my working playboy machine and swap the MPU board.
still the same. have i elemanated the mpu and sol board from being the problem?
When you press the small red switch on the sound board it makes a low tone noise.
the  U1 chip on the sound board get really hot you cant touch it, is that normal?
What should i do next??

thanks for the help!!

Ace.

Did you check for Dry Joints on the Sound Board ? Could be a connector issue - but you have isolated the problem to the sound board. Try reseating any socketed ICs on the soundboard.

[Mr Pinbologist]

From what i gather you were working on the 5 volt regulator circuit?  leaving the bolts out of the case of the regulator would've fed close to 12 volts into the other boards!! so i would say if U1 on the sound board is getting too hot to touch its been fried. Is the rest of the game working?? Are any other ic's getting hot??

[Ace]

i have resoldered dry joints on sound board and reseated the IC's.
still the same ,this one has got me
Iam trying to think back what i did. changed a LM323K 5v without the bolt which makes the 3 connections i only had 2
yes U1 is getting very hot. only this one. yes, every thing else works.
i remember once when fixing my adams and the screw driver bridge across a coil lug and a switch lug and cooked the switch matrix chip.
have i done something like this?

thank for all your help

Ace.

[Mr Pinbologist]

As i said, leaving the screws out would've fed 12 volts intoll the other boards connected to it, so i hate to say it but its possible you may have toasted a few more ic's as well. especially any TTL logic ic's as they hate anything more that 5 volts. does the original mpu still function/ was it hooked up when the sound board died??

[Ace]

Yes the MPU bourd was still hooked up when it died. the mpu board functions with its 7 flashes i even change the chips over to another mpu board.
this dont sound good.What should i do next ??
can you buy new IC's??

Ace.

[Mr Pinbologist]

Well thats pretty good that you get the 7 led flashes, it seems that the mpu survived.. incredible actually!!

Most of the ic' s should be available. i know they can be found for the mpu... just not sure about the sound board Maybe someone else could chime in with some more advice re availability of parts for these boards, as i've never had to source parts for one of these??

Cheers.. Mitch

[Ace]

Thanks for your help mitch, i hope so.
i guess i have learnt the hard way. i want be doing that again.

Ace.

[Skybeaux]

U1 is the AY-3-8910 ,$10 posted if you need one.
I also have every other chip on the board if you happen to need them.
Just send me a message

[Ace]

Thanks for all your help guys!!
Ill try replacing the U1 U2 U3 U10 chips first.
does anyone know what should read out of the Test points on the AS 2518-51 sound board?
TP1-
TP2-
TP3-
TP4-
TP5-
TP6-

I will check these as i dont want to cook any more components.
all other boards are 100% OK.
can bad caps or resistors or diodes on this board cook chips??

thanks!

Ace.

[dj10555]

The voltages at the test points can be found by looking at the sound board schematic for Silverball Mania on IPDB.

TP1 11.9 +-2.5VDC 0.1VAC
TP2 5+-2.5VDC
TP3 GND

The first three are the inputs from the power supply so these should definitely be checked. The other test points are for trying to troubleshoot the board with a multimeter, which can be done but it is much better to use a CRO. If U4 is faulty/suspect you will need someone with an EPROM burner to verify its contents. I have seen other Eproms go faulty due to wrong voltage being applied to them. Generally a faulty cap, resistor, diode on the sound board will not cause damage to the chips, the board will just not work. It is very unlikely these have failed and more than likely to be U1 chip + possibly others.
You could try to replace U1 first, then U2 and U10 borrowed from another Bally -35MPU. Failing that I would get U4 verified which I can help out if you get stuck.

regards Derek

[Ace]

Hello Guys!

ken sent me over the U1 chip, got it wednesday,put her in all good
i was lucky, i only cooked that one chip.
Lesson learnt always bolt the voltage regulator to the board before testing!
thank you to everyone that help me with this problem.
I hope i can return the help one day.

cheers

Ace.