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Bally Squawk & Talk Sound card - issue - Speech becomes garbled after machine been on for a while

AlanJ

AlanJ

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In my centaulr switch on and for about 10-20 minutes the speech sound is perfect. Then after a while it becomes garbled, missing bits of speech, often at the end, but sometimes at the beginning of a phrase. Board has had the electrolytic caps replaced.
Put in new PIA's and 6810 RAM chip, no difference. Tested all the pins to the TMS5200 Sound chip - all make good contact with the board. Header pins reflowed. R9 Resistor consistently measures 130k ohms (Seen the pinside thread about that!)

Running out of ideas now.

Anyone got any other suggestions please?
 
Power supply getting hot and losing efficiency ?
 
I had a couple of diodes on a power supply board causing me issues with a display, 30-45 mins and my display started fading.
Put new diodes in and alpha displays like new again. I like a cheap fix.
 
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For those that may not know, bridge rectifiers are made up of 4x diodes in an integrated component. Diodes do die over time

Some old pros say that you should always rebuild power supplies. Others say that there are so many things in these damned old machines that can go wrong, just wait for them to go wrong.

I dunno who is correct, but I have had various bridge rectifiers/ power diodes fail on my Bally SS and WPC games over the years. My Vector packed up the night before a league meeting once and that was a bridge rectifier that Terry and Dave sorted during the practice time by stripping one off a WPC board I had lying around .......

I now maintain stocks of bridge rectifiers
 
might just get the board out on the bench hook up a speaker and see if the problem is really the board. - they have a self test button that tests the speech so can do a bench test.
 
Could you post a snap when you test it pls ? I have never tested a board "off game" before. Curious to see what folk do
 
Texas instruments tms5200 chip most likely the culprit. Particularlyif you replaced the capacitors. Had a few ebd’s and a Fathom with the same problems.(play for 5-10min then garbled/no speech /parts of speech). All three were good ole “Tms”.......😆
K.
P.s. Jim still has some tms chips. But he may not part with them, as they are Uber hard to find these days. 🙁 @myPinballs
 
Yep 100% the Tms5200 speech ic. I bought 150 awhile back and had to take out a mortgage to do so.. 🤣 almost zero left now in the world
 
Are you using these in your remake boards @myPinballs ? Or did you rework the board to use something else?

TMS5220's are obtainable, but I understand they don't work very well.
 
AlanJ said:
Are you using these in your remake boards @myPinballs ? Or did you rework the board to use something else?

TMS5220's are obtainable, but I understand they don't work very well.
Click to expand...

My boards use the ic (all nos) hence why i invested heavily on these ics when i could get them, and it wasn't that easy then either. You cannot use anything else and produce the correct speech. Its tied to the hardware. In the future i may try to make a pic ic that can emulate it, but for now i am using nos ics and still include them with my new boards so i dont sell them separately.

I do have some with pitch differences that i am not happy with so rejected for use with my boards (yes even though you pay heavily for these, there are still rejects when testing!) You should be able to use one of these if you change a resistor to adjust to the pitch variation. Contact me via pm if interested.

Dont bother with TMS5220 the lookup tables are different and the speech will sound awful.
 
Plot thickens. swapped tms chip out of another machine. works exactly same ok for 10 mins then starts to play up. so looks like the board

to further confuse me. i put the suspect chip into another machine and it didn’t work hardly at all - sound was mostly missing and very garbled. but this might be a red herring as when i pulled the chip out again i lost some of its legs.

now gotta repair the broken legs ......
 
AlanJ said:
Plot thickens. swapped tms chip out of another machine. works exactly same ok for 10 mins then starts to play up. so looks like the board

to further confuse me. i put the suspect chip into another machine and it didn’t work hardly at all - sound was mostly missing and very garbled. but this might be a red herring as when i pulled the chip out again i lost some of its legs.

now gotta repair the broken legs ......
Click to expand...
Sure you don’t want another chip?
 
so i left the good chip in the machine that’s having problems. it’s now working. but. it’s working , I think, because i’ve left the insert door open. it worked for a good hour. closed the insert door and within a couple of minutes the sound started garbling???

heat! cpu running quite hot, swapped that with a brand new one. no difference.

i can open the insert door. sound is perfect. close the door and soon it starts to go funny.

must have a dry joint or crappy ic socket or something.

Anyhow. gonna fix the old tms chip and see if that does the same.
 
Got some new legs in the old suspect tms chip. first time i’ve done this. quite fiddly. put the chip in a socket, then clean up the amputated stumps, then insert a donor pin and solder the two together. getting the old pin stumps clean was a bit tricky as don’t want to lose that remaining bit.

Plugged it back in the suspect board. works fine. until i close the insert door and it soon goes wonky. So. summary is this is most likely a problem elsewhere on the board. (i would have now swapped chips to the other machine again, but don’t want to mess up the other chip and break any of its delicate legs. )
tbc.........
 
So when this issue occurs does the background sound and sound effects still work ok or not?

If it really is just speech related and you are 200% certain the speech chip is ok then check the gi wiring to the backbox door and to the sound board j1 connector. The -5v is created from the ac gi voltage and -5v is needed for the speech chip. Nothing else on the board uses it
 
cheers Jim @myPinballs - i’ll get a test on that -5v. and the ac 6.3 coming in. i’ve found i can aggravate the problem by flexing the pcb, so i’ll test to see if either drops out
 
Checked all the voltages today on the board, all good constant -4.99v on the -5v supply.

Started to suspect the ROM chips or the sockets or the traces to those ROMs. So I took out the board and had a real close look. U4 ROM has gold legs, Looking with a magnifier I can just see one of them is cracked. Pin 12 - rather important GND pin!!!!! As soon as I moved the chip a tiny fraction in its socket the pin feel clean off - right at the edge of the packaging, so no way to repair. So maybe this was the culprit? Dunno now as I'll have to get a new ROM in it. I will borrow the one out of the 2nd centaur I have.
 
Ps forgot to mention. I don’t like the look of the rom chip in the other machine, could have brittle pins. so not going to risk damaging it by trying to remove it from it socket.
 
Decided to have another look at eproms. A few months ago I had a go at learning about roms, proms and eproms and I thought I knew enough - bought some eprom chips 2732 and a cheap TL866 eprom progammer. It didnt work! I sent the programmer back and got a full refund. (For information those cheap TL866 programmers don't do the higher voltages that the 2732 eproms need - any they run rubbishy flakey software).

I spent a ton of time yesterday researching properly and I've concluded the GQ-4X , 4X4 from Mcumall is the way to go. £109 cheapest on ebay - delivery next week. Checked on Amazon - £80 and they can delivery today ! - Wow - so I have bought one.

I then went to look for the eprom chips I bought a while ago - not where I thought they would be. I seem to have stuff in the pinball room, in the garage and in the office. Could be bloody anywhere.........

Anyhow - I am 100% convinced my problem is faulty U4 EPROM, with that cracked leg - so hopefully I will be in business later today. Got 10 hours to find those roms according to Amazon my delivery will be by 20:00 tonight. Hoping its sooner............

I'll also install the eprom programmer software and have a read of the user guide whilst I'm waiting.
 
I have a gq-4x and a tl866 and have never had a problem writing 2732 eproms on either,I have found the gq-4x can be a bit more fussy with other eproms though
 
I also did some research into programmers, consensus of opinions on the internet seemed to be some of the cheap generic ones could be a bit fussy on what they would work with. I bought a Dataman 40, it was superb, so superb I upgraded it to the Dataman 48, which is just as superb but can also program devices used in my SEGA racers. Never had any issues with the programmer, always reliable.

I offered the Dataman 40 on here for sale at what I thought a reasonable price, zero interest, I put it on eBay and sold it for a lot more than I was asking on here.

Chris.
 
stevebm1 said:
I have a gq-4x and a tl866 and have never had a problem writing 2732 eproms on either,I have found the gq-4x can be a bit more fussy with other eproms though
Click to expand...
apparently there are different versions of the tl866. the earlier supported higher vpp voltages. the later one doesn’t. that’s what i bought. then to further confuse there are chinese clones of varying quality.

i’m getting impatient only 8 hours 40 minutes to wait until my amazon delivery. 😂
 
taz turbo said:
I also did some research into programmers, consensus of opinions on the internet seemed to be some of the cheap generic ones could be a bit fussy on what they would work with. I bought a Dataman 40, it was superb, so superb I upgraded it to the Dataman 48, which is just as superb but can also program devices used in my SEGA racers. Never had any issues with the programmer, always reliable.

I offered the Dataman 40 on here for sale at what I thought a reasonable price, zero interest, I put it on eBay and sold it for a lot more than I was asking on here.

Chris.
Click to expand...
ah! timing eh. i would have bought it. today. as long as you could deliver today 😂😂😂😂😂. not really an amazon fan but i couldn’t turn down the price or the same day delivery.
 
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