It probably can. Those are always pretty toasted. Replace with a beefier diode like 1n4006 or 1n4007.

Hard to tell if are those the replacements, or are those the toasted? It looks like maybe someone tried repairing it already - but one looks cracked open. Is the board working? Looks like the pads are gone, and the thruholes are questionable. If you have any experience soldering, it shouldn't be too difficult to fix up though. Just need to run some wire strand thru the thruholes and new diodes, and replace that cap too.

Either way, yea it's fixable, it probably just won't look brand new. I can work on it if you want.

The problem here is current not voltage so using higher voltage version diodes with the same current spec (1 amp) as the 1N4004 currently installed won't make any difference to them cooking.

These are 1.5 amps and physically bigger to dissipate heat a little better:
https://www.greatplainselectronics.com/proddetail.asp?prod=1N5397

I'd probably install 2 amp diodes for more headroom.

I am working on these boards for timab2000. I was doing some research and found quite a few pictures with resistors in place on CR1-3. The manual definitely shows diodes for CR1-3. Around the web I see both but no distinct difference (or board difference). What is the difference here? I haven't looked at mine yet to compare.
pasted_image (resized).png

These are also diodes in a different package.

When replacing the diodes let them float about 7-8mm above the PCB. Also...replacing the old masked rom's by 2532 or 2732 (re-jumper) Eproms is recommended. You will reduce the current draw by 250 to 300mA! The diodes will be very happy with this.

Marco

https://pinside.com/pinball/forum/topic/xenon-vocalizer-eprom-repair-vids-guide

Here is how to replace masked roms and jumpers

If you wipe off the dust, you will see those are actually glass diodes.

Like Marco says, make sure the replacement diodes are mounted well above the circuit board for proper airflow.

Ah okay. The one I'm actually working on is the pic from teh OP. I just saw a bunch of pictures with the glass diodes thinking they were resistors and it confused me.

So the vocalizer is working great now, but surprisingly the sounds plus board doesn't work at all (no vocals or sounds).

TP's have close to correct voltage(mostly a bit higher). The speech potentiometers is testing bad so will replace both of those - but that doesn't explain why the sounds aren't working. I didn't have enough caps to replace the caps on it yet, but they all test fine. I don't have a logic probe for the chips but did the 'diode' mm test on all the chips and they all seem fine (compared outputs to a working sounds plus board). The amp seems to be working fine. While I wait for a few parts I'm wondering if there might be anything else I'm missing? I don't have a way to check the crystal. A few other threads talk about U1 possibly being problematic?

Edit:

To clarify, I have a working set of vocalizer/sound plus so I can mix/match to test. The vocalizer is working 100%. The sounds plus does not have any output at all, aside from some static when you adjust the pents (and a bit of a high pitched hum). If I hook it to either working vocalizer, no sound at all comes out - speech or sound. I've swapped the ribbon cable to a known working one.

Best way to diagnose this board is using the test procedures in the Bally repair manual FO 560-3 instead of shotgunning caps, etc. it will save you a lot of time.

I've looked into this, but it still is a bunch of part shotgunning. I mean, my symptom is 'no sound' I will however run through it and see if anything stands out.

It is Always good to replace the old caps at those boards. And the potmeters. Sometimes the crystal has cracked solderconnections. You can also test the digital part of your board with a testrom

http://www.pinwiki.com/wiki/index.php?title=Leon_Borre_Bally_-51_and_-56_Sound_Repair

Ever get this working? What was wrong?

No logic probe no solution. You can replace all the caps and pots, but that's usually not the problem. DMM and logic probe and the Bally repair manual and you will find the issue. Replacing everything on the board is nuts.

Not planning on doing that I have the schematics and a working set to compare readings to. I can tell most of it is good but a couple flaky items. I'm pretty sure there are multiple chip issues..U4 is bad, but been short on time to really dig into it. You are right tho, I have DMM and Schematics, but I don't have a logic probe.

It’s always only one issue on this board. With out logic probe you will pull your hair out.

All the caps and pots didn’t fix it. Not unusual. A logic probe costs under $20 on eBay. I’m sure you have spent lots of hours.

yea I ordered one tonight since I just need one anyway eventually. I'm not a pro at this by any means, just learning. Had some time to look at it tonight. Here's what I found so far.

U10 is bad (chip bad)
U4 is bad (broken legs)

All other chips test good.

voltages for some pins on his board for U3 seem to be way off compared to my board - for example where a leg should be .18vdc, it's 2.05vdc. (U3 chip is not bad). Pins 38/39 however do show the correct voltages.

Putting a good U10 and U4 in the board does not make the board do anything, so there's still some other issue I've not found yet.

I know where to get a programmed U4, but does anyone know where to get a programmed chip for U10? Or know someone who can do it?

I know the cable to to the vocalizer board is good, but is there an easy way to test the J3 pins to see if anything is coming out of them? I wonder if the 2 boards aren't talking.

dothedoo - this is an update from timab2000's other thread.

How did you test the IC’s? A dmm can’t reliably test those. If you have a working board swap in the chips. U10 is simply a 6810 ram. Nothing to program. Same chip as U7 on the mpu. So you can swap that in. Check voltage at test point 5. Should be about 2.5 volts. If not, at least one IC is bad(including Y1).

There is also a reset circuit on this board. If it doesn't reset properly, the processor wont be running. Measure DC volts at pin 3 of U6 with the power off. Hold your meter lead on that pin while powering on. You should see the voltage jump from almost 0 to around 5 volts when the power is turned on. If not U6 or one of its related components is faulty(a diode and a resistor just below U6 should be checked).

I swapped them into a good board one at a time to test them. TP5 has the correct voltage. I also had tried swapping in good chips (out of the working board) and there was no change in symptoms.

Check the reset circuit.

Next check the op amp. Chip that sits between the volume pots. With power on probe that chip’s legs and the components next to it with your finger. Do you get a loud hum?

U6 pin 3 is acting as expected. I did however find that C27 seems to be bad and possibly CR2. I need to pull it and check it to be sure.

The amp appears to be working.

One thing that is interesting is how different the working and non working boards are in terms of parts.

Non-working soundplus board

0301191723a (resized).jpg

Working soundplus board

0301191723 (resized).jpg

I did a little digging into the difference between using the diodes and the one reversed diode versus the resistors on the top picture. I'm sure that is related to a design change at some point to lower the amount of heat?

If you're talking about the different looking parts at C17, C20, C21 and C24 between both boards they are actually all capacitors, just from different manufacturers.

Yea, slowly. Sorry it's taking so long, but work has been crazy this month and I've been sick for the last 2 weeks. Whether or not I've found the smoking gun remains to be seen. I've been holding off ordering more parts until I think I have found most of the bad parts because shipping is crazy for 1 or 2 little parts.

I'm going to swap out C27 tonight and the working chips and see what else might be wrong.

Really? Huh...well I guess that makes sense since they are marked "C"....but i just assumed those things that looked like resistors were resistors. (I admit I didn't really check the schematic for the diagram of what they are).

You might notice that some Bally MPU boards have a lot of green color banded capacitors that look like resistors too. Easy assumption to make.

Okay I did make some progress and the soundplus does indeed work after some chip swapping, but the results are very strange so time for a sanity check because it has me scratching my head:

Here is what I do know:

2 sets of Xenon vocalizer/sound boards 1 working (mine), 1 not working (Timab's). From here on out Timab's will be referred to as H and mine as M. Vocalizer as V and Soundboard as S.

MV -> MS = working (baseline)
HV -> HS = non working
HV -> MS = working
MV -> HS = working (after swapping out known good U3, U10, U4 on the soundplus - Oddly U3 works in MS, but does not work in HS - you can hear the sounds in the test, but it is all just static and garbled. If I put it in mine, it works fine, and if I put mine in his, it works...)

I cannot get both of his boards to work together. Both cables do work so it definitely isn't the cable.

What I did find is that the soundplus C27 is actually good, but on both sets of boards to get any reading out of it MV must be attached. It does not give a reading with HV attached. (diode check - I know not the actual way to check a cap but it works when doing comparisons). I see the same outcome if I attach HV to MS. C27 does run to U4, and a path to pin 8/9 of J3 has an interaction.

Regardless though, I can't quite wrap my head around why I can get both his boards to work if attached to my boards, but not his boards together. I assume at this point that there is something else wrong on HV, but like I said, it works 100% with MS.

TL/DR: His boards together don't work. Either of his boards with either of my boards work 100%. I had sort of tested this before, but I hadn't swapped any chips in the soundcard at that point so it didn't work with either vocalizer the last time I tried.

I agree that it seems like the 2 boards aren't communicating. I have already tried swapping the cable out with no luck. Your cable works fine on mine though so I'm pretty sure it isn't the cable, and it isn't J3 or the board wouldn't work when hooked to mine.

The only thing that happens if your two boards are together is this low volume high pitched pulse. Is there a specific point I can check to see if the two boards are communicating?

I will post some more pictures later, but there's another difference in our boards that I'm not sure what to make of.

LOL. Part of me says just swap the boards, and we'll have 2 working sets of boards....but I'd like to figure this out because it is so strange.

I wondered if maybe it was something to do with jumpers and chips, but those all look to be correct.

Also, can someone give me some details on the U3 chip - is that the same deal as U10, just replace? Or does it have some programming on it?

U3 is a 6800 cpu. Nothing to program.

So I replaced the chips (which I already knew were only part of the issue). Oddly, the new U10 chip doesn't seem to work correctly on his board. My U10 chip works in his, and the new one works in mine..so I guess I can just swap them, but I'm unclear why this would be. The video shows what a logic probe sees on his boards when they are together. Constantly pulsing, and some erratic 'noise' as well.

The other odd thing is that on my vocalizer board there is no cap in C25, on his there is. I tried removing it as a test, and his board won't work without it. The reason I think this is a voltage issue is that his vocalizer board (diodes and amp) get hot pretty quickly, but I'm not really finding any off voltages. I know I must be missing something simple here, but I can't wrap my head around the symptoms.

Maybe the socket in U 10 is bad.

Problem is probably on the Vocalizer board. I think there is a voltage regulator on there. Test what voltage it’s outputting.

Yea I considered that and am going to swap it, but it doesn't seem to be inconsistent, so not sure if that's it or not.

Okay I'll check that

Does his vocalizer work with your sounds plus board?

On his sounds plus board take these two voltage measurements. TP5 should be close to 2.5 volts. TP4 should be zero volts. If either is not right, you have at least one bad socketed IC. This is the first step in troubleshooting this board.

Yes

They were right when I tested them, but I will look again.

At this time I believe the test switch is good. I am able to trigger the test fine when it is hooked to my vocalizer. I did check TP4 again as jj44114 suggested when your boards are together it was stuck at 5v constantly which it should not be. (It should sit at 0v and jump up when sounds are played - test triggered). So to compare, I then I put your sound board with my vocalizer and ran the test and saw what I missed before. It does start out sitting at 0v and jump up during the test, but it would crap out on the very last test sound and then the voltage sticks at around 2v. In addition the game sounds don't play - which they did before as did the sound that crapped out(which is the power up sound). I replaced U4 socket on the sound board (which I had intended to do initially) and the voltage appears to be correct at TP4 when your boards are together now, but still seeing that constant noise on the circuit and nothing works.

If I connect it back to my vocalizer I can see the voltages are correct at 0v and jump up when I trigger the test, then eventually drop back to 0v, but no sounds coming out (this is new). I tested each pin on U4 up and down the circuit for continuity and making sure no continuity between pins and everything looks good. I decided to take a break at that point as it was pretty late.

So I finally had some time to dig into this a bit again. I replaced all the sockets and found 1 trace that was completely off the board on U3 under the chip. Once that was all fixed, I traced out every single pin on U3, U2, U4, U10 and they are all good and go where they are supposed to per the schematics (back to J3 pins where applicable).

I then went thru that Bally sound board test page as best I could with what i had. The only voltage differences I could find is that R1 on the vocalizer is 5v in - and 1.5v out (per that test instructions and my board, it should come out .24v) - which feeds to the SB+ U2 pin 25 as being high. Since the vocalizer board works fine with my boards, I'm not really sure that +1.3v actually would cause an issue but not really sure. Does anyone know?

When you hit the sound test it still acts like it goes into test - voltages jump, but then they stick that way (and of course no sound).

All the chips have been tested good. The AY3 chip tests good, but I have not replaced the socket on it, however all the testing I did shows good continuity from the chip legs to the place they run to.

Amplifier is tested working.

The other checks I have done is compare in and out voltages and resistance as needed from the working boards to the nonworking board and I find no differences --- they even seem to be the same when the test is running, except the logic probe does show erratic behavior on the non working board when the test is started. (like in the video above).

Made a little progress, but need to validate with some people.

I'm pretty sure that U6 on the sound plus is bad. Pin 8 reads a constant 1.56v (normal should be ~.20) This in turn feeds to U10 - pin 12, U2 - pin 23 and U3 pin 25 which all have the higher signal. The probe reading on these pins is....odd. When I start the test, these pins and U6 pin 8 goes nuts (I think in there is probably something to U4 i forget off hand).

however I have managed to get it to actually make some sound during the test - distorted and it gets stuck

The other thing I found is that the U1 and U2 DA pins/lines are constantly 5v and drop around .20-3v while the test is running. On my board they show as .20 normally and go up during the test.

What I'm not clear on is if these are related or 2 separate issues? I know that pin 8,9,10 of the U6 inverse gate - and the output does come out as 5v on pin 10 which matches mine, but pin 8 is definitely different and seems flaky.

Am I on the right track here?

Could be. Pull U10, U2 etc. one at a time and see if the voltage on U6 pin 8 changes. Eliminate those first as the issue since they are socketed. If those are not changing the voltage when pulled, I would replace U6.