Yet another Spectravideo SVI sound issue...

By MSX_bear

Rookie (29)

MSX_bear's picture

14-03-2006, 23:13

Another post about the loud PSG-sound from the SVI-728! Eek!

Well, I replaced the resistor next to R53 (as mentioned in and sure, now I hear the SCC-sound very well. But something is wrong, it seems the PSG-sound is too low, but the noice generator is still at the same level! The clicks when typing compared to the play command with all three channels produces a noticeable lower volume.

Any idea of what's wrong?

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By MSX_bear

Rookie (29)

MSX_bear's picture

17-03-2006, 10:25

Please, anyone? I've used a 150k resistor and the soldering seems ok. (I don't have much experience, but...) Is it possible that I've damaged something?

By mohai

Paladin (991)

mohai's picture

17-03-2006, 11:27

I had same problem in SVI 738. It seems that 150K is too much. Try 56K, 47K or so. Also, you can try to get stereo sound Smile


Enlighted (6011)

NYYRIKKI's picture

17-03-2006, 12:53

Yes, this is true, that key click sound volume is not changed. This is because key click sound is produced by PPI not PSG. Noice generator is part of PSG, so that actually is playing in same volume than other PSG channels.

To correct the problem, change resistor that is used to controll key click sound output. I don't know what is the resistor number, but you can find key click sound output from PPI (Intel i8255) pin 10.

By ro

Scribe (4861)

ro's picture

17-03-2006, 14:10

or disable keyclick Smile

By Haohmaru

Paladin (774)

Haohmaru's picture

17-03-2006, 14:13



By MSX_bear

Rookie (29)

MSX_bear's picture

21-03-2006, 14:59

Thank you so much for your replies, I took what I could find, a 20k resistor and that's way better then 150k (and obviously the original 4.7k)!