Any Bally experts out there? I have some voltage questions 1978 Playboy

[poppo]

  Glad you got it working.

[jbshocks]

cleaning the volume control seems to have solved the hum

[jbshocks]

OK its a sickness.  Anyone know a good therapist?  I just bought another one.  Another 79 Bally, this one is called super sonic.  I don't think it has run in 30 years.  It is in very good shape but the MPU was just toasted with battery damage.  This time I didn't even fool around with trying to delicately clean it.  I neutralized with vinger/water, put it in the dish washer, baked it in the oven, bead blasted it and then rinsed with isopropel alcohol.  u11 was shot.  I changed the sockets in u7,u8,u10,u11.  I borrowed chips from playboy and it flashes and flashes and flashes and flashes and never stops.  Any thoughts?  I may rejumper for 2732's and make one of those test chips.  I really should have bought more of those eproms.

[poppo]

I may rejumper for 2732's and make one of those test chips. 

I think that is your best bet.

[CVslots]

OK its a sickness.  Anyone know a good therapist?  I just bought another one.  Another 79 Bally, this one is called super sonic.  I don't think it has run in 30 years.  It is in very good shape but the MPU was just toasted with battery damage.  This time I didn't even fool around with trying to delicately clean it.  I neutralized with vinger/water, put it in the dish washer, baked it in the oven, bead blasted it and then rinsed with isopropel alcohol.  u11 was shot.  I changed the sockets in u7,u8,u10,u11.  I borrowed chips from playboy and it flashes and flashes and flashes and flashes and never stops.  Any thoughts?  I may rejumper for 2732's and make one of those test chips.  I really should have bought more of those eproms.

Wow...yeah, i wouldnt consider what you did "delicate cleaning" anyday....

[jbshocks]

I changed jumpers and flashed a test prom.  blinks per test then when pressing the reset switch to test memory that tests ok.  reburned to playboy and stuck the board in the playboy.  It poped some solenoids and made some music but didn't really work. Then it would flash 2 lights and stop.  I guess I need to see if I have any more bad traces.

Poppo,  if it is blinking would that indicated that the transistors and such from the corrosion kits would not be needed? 

[poppo]

Poppo,  if it is blinking would that indicated that the transistors and such from the corrosion kits would not be needed?  

Which test ROM are you using? But yes, if it's flashing then it has completed a reset. Plus since you got some activity out of it (a little music etc), the reset must be working.

[jbshocks]

I was using the test rom you sent me.  The music was when I put playboy roms back in.   The funny thing was that I got music to early in the boot cycle.

[poppo]

What does the MPU LED do on power up?  As long as it flashes, the reset is ok.

FYI, the sound board is sort of self contained. It has it's own processor so to speak, and it can generate music or sounds just by the address/data lines toggling. So just because it's playing tunes, does not mean it's being told to intentionally.

[jbshocks]

with swapping chips and such the playboy board stopped working.  I started to sweat it.  It wouldn't blink with even just the test chip and processor.  Pin one ground seemed weak on u11 but supposedly you don't need 11 in to blink with that test chip.  So I swapped out the socket and now it is working perfect.  It actually had 2 corroded pins, 1 and 2.  I was really afraid I ruined it.  So I decided to order a logic probe to dig in further on the super sonic board.  So nothing more on that one for a little while.

[poppo]

A logic probe really can come in handy.

Corrosion under pins can be a real issue too. Sometimes just using a lot of liquid flux on both sides and re-flowing the joints will help. Easier than replacing sockets unless you have a nice rework station. Corrosion between pins can be a headache too. Using a stiff nylon brush or a toothbrush when using the vinegar/water solution to try and get between the pins will also help. The corrosion can be conductive and while not be a direct short, will cause all sorts of issues. That's one of the reasons I just gave up on the old boards and ponied up for a brand new one. Nothing worse than having a really good game going and have the MPU glitch.

[poppo]

I really should have bought more of those eproms.

If you have not bought any yet, you might try this guy in China.

http://www.ebay.com/itm/320674406737

He took $2.00 a piece offer on 6. They are new, and programmed ok (although my Willem is really twitchy with 2732 chips). The ones I got were 2732A 21V programming voltage.  Got them in 8 days which I thought was pretty good.

[jbshocks]

I got this other disaster of a board running.  After changing several sockets the thing would blink and never stop blinking.  The root cause was Pin 9 of U7 has a trace on the back side there is a through hole bringing it to the front almost between pin 1 and 2 of U11. This through hole was open and difficult to spot. With that line open the LED just blinks. once I repaired the hole I would get the unique first flash that I am used to and a total of 6 flashes.  The 7th flash was solved by replacing r113.  Now it works.  Who knows if this thing will be erratic or not but the fun was in the challenge.  Considering the cost of a new board my time was probably worth 5 cents an hour.  The logic probe really came in handy and found the open.  I basically went pin to pin on the ICs and any time I found a pin with no hi, low or signal I would investigate.  It seems there are a few unused pins but you can narrow it down quick.  Now I want to set up a test fixture and chase down the rest of the sound on my one no sound ultra board.

Thanks  Poppo I appreciate your guidance.

[poppo]

Glad you got it working.  I can't tell you how many hours I spent fiddling with those MPUs only to be playing a game and have it lock up or something.  That's when I said the heck with it and just bought a new one. BTW, you can buy unpopulated MPUs on e-bay if you want to spend the time transferring all of the components. 

[jbshocks]

I saw those and considered it. but this is really a spare board anyway so it was more to see if I could make it tick again.

[poppo]

.... it was more to see if I could make it tick again.

You need a new avatar.