6803 mpu coming soon. Over 500 components per board .
6803

Sounds deluxe available now
sounds deluxe

Now available. Nvram.weebly.com

Check/swap the AD7533 and the service bulletin about the capacitor that blows up that chip. In my testing I have noticed an AD7533 may not totally fail, but just give you "scratchy" sound.

http://www.pinrepair.com/6803/6803removecap.pdf

Push the diag button on the sound board. It should make noise. Does that sound clear?

I am not too familiar with Dungeons and Dragons, but this sound board should be relatively "good" sounding. All the sounds are samples, including the tones. Escape from the Lost World I think sounds pretty great with this board, it plays a neat song at least a minute long. Special Force is kind of bad sounding in comparison though. Maybe find some youtube videos to see what your game should sound like.

On the new sound board the connector pins will have some labeled S1, S2 and etc. With a logic probe in sound test you should see activity at each one with a wire. Missing one input signal would result in wrong sound, not scratchy.

if two boards sound the same, its probably not the circuit board trim pot. Change / check / clean the cabinet trim pot though. They are usually bad in these bally games by now if original. Bad trim pot is possible to sound scratchy, but usually you can find a good spot. You can maybe take it apart and clean / adjust the wiper. I have fixed my atari 2600 paddles a that way. Sometimes they need replaced if the wiper part is bad or the winding it open up between the outer legs.

Make sure the correct speaker is used and not busted up. The cheap speaker used on my test fixture sucks and they all sound pretty terrible from it. The speaker in my Special force / Black Pyramid sounds so much better.

Wow, D&D has eight minutes of music. It is kind of neat, but I hear the "scratch". It is almost like what low bit rate MP3 rip from 1997 sounds like. Perhaps intentional to sound gritty like that?

Special force has like 10 seconds of music, no speech, and cricket noises... lol. I could not find a Escape from the lost World soundtrack video like that D&D one, but it is pretty good. I will have to explore the other sounds deluxe games.

If the 330ohm resistor is vaporizing that usually means the coil dead shorted or there is a short circuit around the coil.

Find the coil associated with this transistor, measure ohms. If it is shorted (zero ohms), cut the diode off and check again. If it is still shorted, or looks burned up, it needs replaced.

When the coil is not turned you should be able to measure volts DC on both sides of the coil. If the voltage is missing check the fuses.

I stopped making the 6803 power board because it had too many through hole parts and it was huge. I got notice the MJE3439 HV transistors I was using are going obsolete so it was good time to surface mountize the 5v and HV regulator circuits and redo the 6803 PS. First time really use SMT 10A1000v power diodes, SMT EL caps, SMT switching V-Reg. Tempting to use the SMT fuse holders but I stopped there. More parts I can automate assembly of, the more things I can keep in stock.

6803ps (resized).png

All good. I had to order the 2pin connector. Once it's here I will list the power supply board for sale.

20220712_020533 (resized).jpg

Yes. The 14v and 43v ones are on the DC side of things but should indicate the fuse is out most of time unless something crazy happens like the bridge diode blows open which shouldn't happen since the diodes are current rated ~4x over the fuse values.

The 14v fuse will be a different color than the rest on the first round of boards. I changed some labeling of the 14v from 12v to better match the original documentation and it wound up breaking a link to the LED in the assembly files.

I did not LED the high voltage. I know commercial devices that have a simple LED circuit even on 220vac mains, but HV makes me nervous. More stuff to short and blow the fuse.

I think it is complaining about a stuck closed switch.