By pressing SW1 the diagnostics switch, I think would bypass this signal in ether state.
The board shows no indication a jumper was every there. Jumper w12 is questionable, jumper 12 shows going to IC10-17 which is an input. Thanks for the help and please correct me if I get any of this wrong. I could not find a theory of operation for the D8224 sound board and need to know the order in which IC9, IC10, IC11 and IC12 communicate to troubleshoot further. I’m guess IC9, micro sends data to IC12 the ROM/PROM then IC12 send the information to IC 11 the RAM which then send information back to the IC9 and then to IC13 Pins 5-12 (data lines to IC13) have no activity at any time. Before pressing the diagnostics button pins 26-33 (address lines)have no activity but when diagnostics button is pressed I see signals of 5VDC Vp-p that are changing. Monitoring IC9-6 with an oscilloscope and pressing the diagnostics button cause voltage to go from 5VDC to 0 VDC the back to 5VDC. Injecting 1 KHz sine wave at Pin4 of IC13 (audio output) produces sound. €¢ W1, 3, 4, 6, 8, 11, 12, 13 not connectedĭisconnecting Speech board, adding jumper for W1, putting DS1 switch 1 and 2 to off and momentarily pushing diagnostic switch provides on sound or speech.Īdjusting volume control below playfield provides hum from speaker at max volume. Unit then unit goes back to attract mode, both LED go out, digit display on CPU board goes blank. Momentary pushing diagnostic button on CPU caused users displays to blank, LED on CPU to flash once the digit display on CPU board to indicate 0. The previous owner said it had sound at one time. I purchased this machine a couple of weeks ago and it has never had sound. No speech or sound from machine but unit appears to work.
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