(Topic ID: 108116)

Firepower speech disappeared

By jedi42

9 years ago


Topic Heartbeat

Topic Stats

  • 26 posts
  • 10 Pinsiders participating
  • Latest reply 9 years ago by Schwaggs
  • Topic is favorited by 4 Pinsiders

You

Linked Games

#1 9 years ago

After some great help from the forum, I got a Firepower pin working that I had acquired. After fixing, we had been playing it for 3 weeks with no issues, and during a game the speech suddenly stopped. When it happened, both the sound and speech stopped mid-game, but could faintly hear some sound if I turned the volume level all the way up.

- checked the pot, and if I turned it up a bit, the sounds came back, but no speech

As I was reading posts and schematics, it seems that in order to have speech the option switches both have to be turned on. When I looked at mine, one was on, but the other was not. If that is the case, how was I getting speech for the last month? Switching them both to on did not enable speech.

In one of the posts, it sounded like IC3 on the speech board could be the problem, but also says to replace it as a last resort.

The schematics for the sound and speech boards says to check for data and speech clock activity. Am I to assume I cannot do this without an oscilloscope?

Any advice?

#2 9 years ago

Amplification issue? Give a good visual check of the small value 1uF cap to the left of the amp (looks like a 5 leg transistor). That one dies the most often and could give you quiet sound.

Possibly a mixing issue? Sound goes to the speech board to get mixed and then comes back? Ribbon cable? Try squeezing the ends tight if they look loose.

#3 9 years ago

The 1uF cap looks ok visually, but not sure how to test it properly.

The cable looks pretty good, seems tight and nothing odd happens when I squeeze of jiggle it.

I was also reading about the pot, and that I should test it. I tried to read the resistance with a DMM, but it only read a constant 3.89, and no change when I spun the dial. I am wondering if i am testing this properly, as it seems to work during powered testing because when I spin during the sound test, it can eliminate the sounds when I turn it all the way towards where speech should be. I assume you just test on ohm setting on the two terminals and spin dial (with power turned off)?

#4 9 years ago

A sign of a bad cap is that it is splitting its wrapper, one side is puffed up, leaking fluid. A lot of times, not always though, you can look at a bad cap and tell it is bad from visual clues.

Set your dmm to resistance. Attach to and end leg and the middle leg, swizzle the pot and watch for the DMM to smoothly change in resistance if it bounces open a bunch, or doesnt change, bad pot. I think it is a 5k pot? If it never changes you can try cleaning it and even taking it apart. Some times this is futile and they just need replaced.

#5 9 years ago

I'm concerned that you said the Voice Enable switch was in the wrong position when you had voice working. I think you need to check to make sure that circuit is working OK.

The switch input to enable voice goes to PIA (IC10) pin 15. Check the status of this pin with your logic probe.

With switch 2 ON - this should read 0v
With switch 2 OFF - this should read 5V

Another couple things to try: With the machine off, slightly raise and re-seat the ROMS on the voice board. If this fixes the problem, you should replace the ROM sockets on the voice board.

Re-seat the ribbon cable.

#6 9 years ago

OK, checked the pot (the 3 legs threw me, as it looks like it only has two), and the resistance is good - went up and down smoothly.

I had re-seated the roms on the speech card yesterday, no change and the ribbon cable seems good (tight and clean).

When I looked, it was switch 1 that was off, but all the sounds and speech worked. From playing around, switch 1 doesn't seem to do anything (although in the schematics it says both need to be on for voice to work, and that it should flip between sounds and chimes). Anyway, checked IC10 at pin 15, and checks out as Schwaggs posted.

#7 9 years ago

Try removing any chip in a socket and reseat, I had a sound board that quit working and it turned out one of the chips had the legs rotted off of them, and were stuck in the socket.

#8 9 years ago

Are you hearing any voice sounds at all, even very faintly?

Switch 1 sets sounds or chimes. It too should be ON to get normal firepower sounds. Seems like your board is ignoring this. Not sure if this points to a problem with the PIA or if this isn't a big deal.

To check to see if Switch 1 signal is getting to the PIA (IC10), check the status of pin 16 with your logic probe.

With switch 1 ON - this should read low - 0v
With switch 1 OFF - this should read high - 5V

To verify a clock signal and data is being generated for the D/A chip on the voice board, check the following pins on the SOUND BOARD PIA (IC10). Use your logic probe and check for a pulsing hi/low signal.

Pin 19 - Speech clock
Pin 39 - Speech data - This may not show anything unless the boards are trying to play voices

#9 9 years ago

change IC3 ( the 1458)

#10 9 years ago

OK, Here are results of tests:
switch 1 ON - 3.7v
switch 1 OFF - 4.8v

Pin 19 (IC10) - when speech supposed to play in diagnostic - .35v
Pin 19 (IC10) - when sounds play in diagnostic - .02v

Pin 39 (IC10) - when speech supposed to play in diagnostic - 2.4v
Pin 39 (IC10) - when sounds play in diagnostic - 4.8v

I wondered about replacing IC3 based on previous posts. I ordered one in case, but will be a couple of weeks before I get them. Any way to test it?

I also just checked for voltages (I don't have a logic probe) on the pins suggested in the firepower.com schematics, which all showed some voltage readings except for the IC1 pin 9 (speech clock activity).

And no speech at all, not even faint.

#11 9 years ago

Squirt contact cleaner on the pot and turn it back and forth.

My fireball classic lost sound. Was faint. Put. A few drops of rubbing alcohol on the pot on the board.
Fixed it right away. Have not had a problem since.

Just a thought. Could be as easy as just that.

#12 9 years ago

please .. no .. dont cover the board in contact spray. The pot at R8 is not a volume control its a balance control.. one side plays sound, the other speech, the middle a suitable ( to the owners ear) mixture.
Turning it up doesnt make the sound come back it just increases its share of the mix .. put it half way.

#13 9 years ago

The voltages when testing switch 1 are problematic. It should be 0 (or close to it) when the switch is on. Lets set that aside for now.

The other measurements are not what we need. I was assuming you had a logic probe. You really need to use a logic probe when testing for pulsing, a DMM will not work for this.

Pin 9 on IC1 is connected to pin 19 on the PIA that you measured. You really need a logic probe to measure activity on these pins.

#14 9 years ago

Get a can of Deoxit D5 for cleaning pots. When I started to loose speech on my Black Knight, I had to replace one of the mixer op-amps IC2 or IC3.

#15 9 years ago
Quoted from wiredoug:

please .. no .. dont cover the board in contact spray. The pot at R8 is not a volume control its a balance control.. one side plays sound, the other speech, the middle a suitable ( to the owners ear) mixture.
Turning it up doesnt make the sound come back it just increases its share of the mix .. put it half way.

Im not saying cover the board. Im saying squirt a tiny bit on the pot. Or ruubbing alcohol. Twist it back and forth to clear any dead spots.

Then set it back to the middle. Or where it sounds best.

If/when it gets a dead spot or goes bad. You will lose sounds or hear them faint. Either clean it. Or replace it first.
Its a cheapbsimple fix. If it stll doesnt work after that then look into it further.

1 step at a time, simplest solution to hardest.
Dont work backwards.

#16 9 years ago

Looks like I will try to find a logic probe to go much further. I am pretty confident the pot is OK, as the resistance test shows a gradual increase/decrease. Doesn't look like I can get a logic probe locally, so may have to order on-line and wait.

#17 9 years ago

While you are ordering electronics, you may want to get a couple PIA chips and 40 pin sockets for your parts box if you don't have any. 6821 is the part number.

3 weeks later
#18 9 years ago

OK, got the logic probe. As per the above posts and the schematic of the sound board, I have found the following:
Pin 39 on SB IC10 - pulses during time when voice should occur (OK)
Pin 12 on SpeechB IC1 - pulses during time when voice should occur (OK)

Pin 19 on SB IC10 - pulses during time when voice should occur (OK)
Pin 9 on SpeechB IC1 - pulses during time when voice should occur (OK)

Pin 3 on SpeechB IC1 - pulses during time when voice should occur (OK)
Pin 7 on SpeechB IC3 -NOTHING during time when voice should occur

So, I am to assume that IC3 needs to be replaced (which is what I had guessed before the testing from the posts I read)?

#19 9 years ago

Not sure your test of pin 7 using a logic probe is valid. Both parts of IC3 is an op amp filtering circuit that shapes the audio signals. In the process, it changes it from a 0-5V signal to a + 12 -12 signal that your logic probe may not be able to read.

You jumped right to the output of the 2nd stage of the filtering circuit. Does your logic probe measure anything on pin 1 of IC3? How about pin 7 of IC2?

At this point, it appears all the digital and D/A circuit is working. IC2 is also working or you would get no sound at all. It seems likely that IC3 is the culprit but it could also be one of the capacitors in the signal path (C1 or C12).

#20 9 years ago

Pin 1 of IC3 (speech board) pulses when speech should be heard.

Pin 7 of IC2 pulses during sounds. Nothing during speech.

Any way to test the 2 capacitors you mentioned?

#21 9 years ago
Quoted from wiredoug:

please .. no .. dont cover the board in contact spray. The pot at R8 is not a volume control its a balance control.. one side plays sound, the other speech, the middle a suitable ( to the owners ear) mixture.
Turning it up doesnt make the sound come back it just increases its share of the mix .. put it half way.

Thanks for posting this.
I always wondered why my system 6 games had two volume controls.

#22 9 years ago
Quoted from Schwaggs:

It seems likely that IC3 is the culprit but it could also be one of the capacitors in the signal path (C1 or C12).

I went through this and resocketed a new IC3 only to have no speech still. Turned out to be a shorted cap.

#23 9 years ago

If you have the caps on hand, I would just shotgun replace them. The fact that you detect signal on pin 1 of IC3 but not pin 7 may lean towards a bad IC3...

If you need to order parts, I would order the caps and IC3 (dual 1458 op amp). GPE should have all of them: https://www.greatplainselectronics.com/default.asp

#24 9 years ago

I have a Black Knight wiht the same problem that you have. When I press the test button on the sound board, It had sound but no speech. And It had a long pause between the last sound and the first sound, like the cpu knew that sould be a speech there.
First I suggest you try with IC 3 at the speech board, change this one first is the easy way. But, In my case, I could find that the problem was a bad pia chip in the sound board.

3 weeks later
#25 9 years ago

Update on repair, it was indeed the IC3. After debating whether I would screw up the board by trying to solder, I practiced on an old board and took the plunge and dropped a new one in, It now works like a charm. Thanks for everyone's help!

#26 9 years ago

Congrats on the fix! Feels good to fix it yourself, right!

Promoted items from the Pinside Marketplace
$ 42.95
Eproms
Pinballrom
Eproms
$ 299.95
Lighting - Led
Pin Stadium Pinball Mods
Led
From: $ 90.00
Tools
Pincoder Store
Tools
Trade
Machine - For Trade
Washington Court House, OH
2,200 (OBO)
Machine - For Sale
Branford, CT
$ 12.50
Lighting - Led
RoyGBev Pinball
Led
From: $ 9.00
Boards
KAHR.US Circuits
Boards
From: $ 649.95
Lighting - Led
Pin Stadium Pinball Mods
Led
$ 150.00
Displays
Digipinball Shop
Displays
From: $ 5.00
Cabinet - Other
UpKick Pinball
Other
From: $ 399.95
Lighting - Led
Pin Stadium Pinball Mods
Led

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


This page was printed from https://pinside.com/pinball/forum/topic/firepower-speech-disappeared and we tried optimising it for printing. Some page elements may have been deliberately hidden.

Scan the QR code on the left to jump to the URL this document was printed from.