Another Joust Sound Problem

dlbuller

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Just got a new sound board from quarterarcade. When I push the diagnostics button, a sound repeats...

Does this mean I need to check the data cable and the PIA on the ROM board?

Any help would be great!

thanks
 
seems like the PIA is on the sound board. I don't think the problem is with the sound board....anybody have any suggestions?

thanks
 
Just got a new sound board from quarterarcade. When I push the diagnostics button, a sound repeats...
No problem, that's what it's supposed to do. Pressing the switch generates a special interrupt to the sound processor, where it goes into an endless loop playing a single sound effect. This verifies functionality of the processor, ROM, PIA, DAC, amp, and speakers. Not sure if it ever changed, but on mine it plays the "thump" sound btw.

LeChuck
 
Thanks for the reply,

I should have posted the whole description. If I don't press the diagnostics button, I get no sound when the game is up. I have new connectors on all my cables and the sound board was purchased in working condition.

Something on the ROM board maybe?
 
Thanks for the reply,

I should have posted the whole description. If I don't press the diagnostics button, I get no sound when the game is up. I have new connectors on all my cables and the sound board was purchased in working condition.

Something on the ROM board maybe?
The data path you're testing now is CPU board -> ROM board PIA -> sound board PIA. Do your coin door switches work (e.g. test mode / advance)? Those go through the ROM board PIA also, so would be a quick way to check its functionality. The most obvious point of failure though would be the sound select wiring/connectors between the ROM and sound boards (header 2J4 on the ROM board, IOJ3 on the sound board).

You could try reseating, cleaning, and checking the resistance of these connections .. but a more direct test would be to manually ground the sound select pins from the ROM board side (since these are active low, it's the same effect as the CPU selecting them via the PIA). You can do this on the connector itself, or preferably at the test points just besides the connector. If the sounds fire, then you can rule out that part of the data path atleast.

Here is a good (very high resolution) scan of the board connections if it helps ..
http://www.cityofberwyn.com/schematics/williams/JOUlay.tiff

LeChuck
 
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Thanks again for the reply. So grounding the sound select yields pins 2-7 working, pin 8 produces no sound. Trace back to ROM board next?

thanks
 
Thanks again for the reply. So grounding the sound select yields pins 2-7 working, pin 8 produces no sound. Trace back to ROM board next?
Just to confirm, did you do this on the sound board or the ROM board? It would be helpful to rule out the entire wiring/connector path by doing this on the test points of the ROM board (the test points are the 7 circular solder blobs right next to the connector). Your other data looks normal; pin 8 is left disconnected as a sound select on Joust.

Also - are you able to enter diagnostic mode and step through the tests with the coin door buttons? If so, do the sounds work from there (I'm guessing not)? If you get sounds from the test points, but not from the diags, then I would start checking the ROM board PIA. If you look in the Joust manual's sound diags page, there is a section for "SOUND WHEN DIAGNOSTIC PUSHBUTTON PRESSED BUT NOT IN DIAGNOSTIC MODE TEST 4". This walks you through checking the PIA outputs and its power supply.

In case you don't have the manual, you can find it here:
http://www.robotron-2084.co.uk/manualsjoust.html

LeChuck
 
Pins 2-7 are the data pins. Pin 8 is the ground, IIRC.

The best way to tell is to go to the sound diagnostic page, make sure it is cycling through the sounds and use a logic probe and look at the pins at the ROM side by touching the wires at the connector. If you have the original wiring harness, you can easily get at the bare connectors on the top. If you have replaced it with a crimped connector, you will need to push the logic probe into the connector until it makes contact. If the wires at the ROM side are cycling, then test the sound card side. You may just have some bad wires.

ken
 
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