Konami PCBs sound problem ?

[Luigi]

Hi.

I have a Konami Amidar PCB and sometimes there is no sound....then it reappears.

I once talked to a collector and he told me that there might be a problem with Konami boards when they are connected to the "wrong" speaker (4 Ohm / 8 Ohm ....I don't remember). He said that a little resistor in the "Speaker +"-wire would solve the problem. Otherwise the on-board amplifier could be damaged.

Has anyone heard of that solution and give me a more detailed explanation?


Thanks

[Hurray Banana]

I've got a similar problem with my Time Pilot, Track and Field and Gyruss boards.

I get no sound out of any of them. The only exception is the 2nd channel on Gyruss works.

I haven't got the time at the moment to look at this problem, but I'd be interested if there is a common speaker requirement for these boards.

[Luigi]

Hi Banana

We are not alone. I know other people having the same problem .... only with Konami-PCBs.

I will post when I get something.

[Q*Bert_OP]

My gyruss has no sound either...

I threw it back on the "dead pile"

[Kevin Mullins]

Have you tried swapping the amplifier transistor?
I know my Time Pilot and Tutankham, and I'm sure many others, are interchangeable.
Top smaller PCB is the sound board.... multi leg transistor with the heatsink on it(LA4460) is the amplifier.
There is also a volume potentiometer on the sound board.
And a dip switch setting for attract mode sound. (dip switch #2, 5th little switch)
The Time Pilot manual shows two 8ohm 6w speakers. (wired parallel I believe)
http://www.arcadedocs.com/vidmanuals/T/TimePilot.pdf