volfied schematics

Raxnahali

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Anyone seen a set of these online anywhere? I've been using google to see what I can find but haven't had any luck yet.
 
yes I do have a problem

Game is starting and attempts to play but hiccups to black screen. It seems to run better after it is warmed up but not well. I hear the game playing in the background sometimes faintly.
I'm going to have another go at it soon. I'll do the usual clock and cpu checks first but things would be easier knowing what I should be looking at.
 
mysteriously...

Ok, so I did find a short in my wiring set up that didn't effect my other games but volfied was definitely miffed!
NO sound...so I dragged my finger across the amp pins and nothing. The amp isn't running hot either, it's kinda warm. So, I'm on the net looking for the amp datasheet seeing where the outputs are on this bugger.
 
If the board is playing blind most likely the TC0070RGB DAC is faulty or nor well soldered.
 
better explained info

Ya typed that last missive off of my phone and I really shouldn't do that. Auto correct and my fat fingers do not mix well with phone typing.

After I found my short I in my test bench wiring, which was pulling Volfied down on the 12vdc power, the game was no longer dropping out. Now I am running without sound and the game otherwise works perfectly.
So I'm going to be sitting down and playing with the pot, amp, grab my probe and see if the ram is doing anything. I recapped the board last night so that shouldn't be the issue.
I have me a schematic of the amp so that should be easy to rule out.
I'll keep you guys informed! I'm hoping a few of my other derelict games have the parts I need to get this guy going.

Thanks for the info Caius, appreciate you taking the time to chime in.
 
Try to determine if lack of sound has digital or analog cause.You could use simple audio probe to "listening" to various points of sound circuit to see it sound is correctly generated but then lost somewhere.I suspect OP-AMPs (IIRC they are present on this board).Check also the DAC.Obviously check first if the Z80 is running.
 
Kk will do. It will be a couple of days before I can do this but ill get back to you
 
Has it been that long since I updated this thread? Well I'll keep it short ;)

- pulled off the daughter board to see the z80 as I noticed it was socketed and had probably been changed in the past. I don't have a schematic but the board is silk screened with a z80a on it. so I replaced the cpu with the proper one.
-replaced daughter board back onto its socket and fired up game. No sound.
-checked clock on cpu, I have a beating heart. Checked clock on synthesizer, it was working also. Checked inputs to synthesizer, there was stuff happening.
-took me a few minutes to find the DAC but it is a chip ym3014b Pin 2 is the "load" or output of the chip and it didn't have anything coming out. checked the input, checked the clock on the chip, signals were there. Also checked pin 8 as the datasheet intimated that it needed a signal that for the DAC to work. Signal was there.
So I've settled on the DAC and have ordered parts for it.
 

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Pin 4 of the YM3014 is the serial data input (digital signal), pin 2 is the analog converted signal which usually goes to the OP-AMP.If you are using a logic probe you cannot check analog signals, best would be to use a scope or , even better, an audio probe to "listen" to the signal.
 
Pin 4 of the YM3014 is the serial data input (digital signal), pin 2 is the analog converted signal which usually goes to the OP-AMP.If you are using a logic probe you cannot check analog signals, best would be to use a scope or , even better, an audio probe to "listen" to the signal.

Used a fluke digital scope for all of my checks at the DAC. My signals matched what was on the datasheet except for the output on pin 2.
I'm going to try this audio probe stuff though as I have bought a logic probe that has a speaker on it. I was told that I should be able to faintly hear what the board is playing if I listen closely.
 
I've changed the DAC

Ok, as the title states I've changed the DAC and now have an output. output goes to pin 3 on the Op Amp situated next to it and that Op Amp has an output.
Still no sound.
I am now looking for my glasses so I can attempt to trace the signal to where it is going next.
https://youtu.be/IipqkArfd4w
 
Volfied sound issues solved!

After identifying the DAC as being bad and replacing it, I still didn't have any sound. My workmate was looking at the datasheet for the op amp 4556 next to the DAC. He asks me if the -5 is there for the op amp....well it wasn't as my test set up does not have -5 on the power supply. When I bought it it was advertised as having it, and it labelled as such but doesn't exist.
I also haven't had a game thus far that used it so my answer was "no". so I snatched the sheet away from him as he walked away laughing...
I then took my meter and checked for continuity back to -5v pin on the jamma connector from pin 4 and sure enough the op amp is looking for this voltage.
I grabbed a separate power supply off the bench and connected it up and the sound works. (ground was isolated on this power supply, this is important!)

So...after many frustrating hours of pissing around even after finding a problem on the board, you will need -5v to run the 4556 op amp next to the DAC.
Volfied is back up and running as expected!
Thank you for your help ladies and gents, appreciate your time!
 
Every cloud has a silver lining... now you have a test bench power supply that has everything it will ever need to have. :)

The joys of arcade repair. Did you ever make the audio probe?

paris
 
After identifying the DAC as being bad and replacing it, I still didn't have any sound. My workmate was looking at the datasheet for the op amp 4556 next to the DAC. He asks me if the -5 is there for the op amp....well it wasn't as my test set up does not have -5 on the power supply. When I bought it it was advertised as having it, and it labelled as such but doesn't exist.
I also haven't had a game thus far that used it so my answer was "no". so I snatched the sheet away from him as he walked away laughing...
I then took my meter and checked for continuity back to -5v pin on the jamma connector from pin 4 and sure enough the op amp is looking for this voltage.
I grabbed a separate power supply off the bench and connected it up and the sound works. (ground was isolated on this power supply, this is important!)

So...after many frustrating hours of pissing around even after finding a problem on the board, you will need -5v to run the 4556 op amp next to the DAC.
Volfied is back up and running as expected!
Thank you for your help ladies and gents, appreciate your time!


This was obvious, we all thought your setup had -5v hooked up.OP-AMPs are most of times powered by dual supply (+5 and -5V).Anyway, having an audio probe would have saved you hours of troubleshooting.
 
audio probe

No, I haven't had time to make a probe yet as I have had too much on my plate lately. I should have made time as Caius has stated it would have saved me a lot of freakin time...
I should have picked up on this -5v a lot sooner...frustrating when the answers are looking you right in the face and you just don't see it.
 
Fixed

In summary this board is up and running with sound! I replaced the DAC and supplied the board with the -5 volts it requires to run the sound. I've been playing the piss out of it for the last month and I suck at it :D
right now it is one of my favourite games!
 
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