Recently, I was playing with a friend's FC200, in an attempt to sample sounds from the PSG. However, once the game was loaded, and I connected the sound output to a PC sound card, the machine went silent.
As of now, all I can hear is the keyclick, and SCC sounds from a Salamander cartridge.
Still, the joystick seems to work fine, which would imply to me that the PSG isn't all dead, but rather that some part in the audio amplification circuit, or, in worst case, the sound part of the PSG, is dead.
Is this case familiar to anyone, and is there a cure? I'm having difficulties tracing the sound all the way back to the PSG with a multimeter.

The keyclick is generated by the PSG, right? So it still works? Does the FC200 have an independant sound output? I don't quite understand what you've done.

Nope. The keyclick is generated by the PPI, and then mixed with PSG sound. That's why you can use 3 square-wave channel+noise+sampled sound (using keyclick).

Exactly. External sounds work fine, so some parts in the sound path (both mono RCA plug and RF) are still working, whereas the PSG is dead silent, while still taking care of joysticks.

That doesn't sound good... (no pun intended) I guess all you can do is open it all up to see if perhaps there's a bad solder-joint or a damaged print-line. No too likely though. If you feel it's worth the trouble I guess you could replace the PSG. It's not that easy to find, but if you do find one they're very cheap and easy to solder. I suggest you cannibalize some other (non-MSX) computer for the PSG for a quick fix. Be sure it's a pin-compatible PSG though, before you go opening up your brother's SEGA

Would an YM2149 from an Atari ST do?

wait, if is a y-3-8910 the chip got 3 pin out, one for each channel, and are soldered in the same print line to mix the sound, so, ¿how can 3 outputs lines broken at the same time?

i think the PSG not got nothing wrong, i think some resistor after the mix with PPI click...
or maybe a transistor...

PLug with a PC turned on is danger if the MSX is turn on. But i think that can't do that. Maybe is a transistor, or when you plug the RCA that strong do that.

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Would an YM2149 from an Atari ST do?

I dunno... I'd start by counting pins... Ofcourse if the chip has a serial number you can look it up on the internet to get the pinout. If each pin does what it's supposed to do there shouldn't be a problem. I don't know the FC200 so I wouldn't be able to tell you what type of PSG it uses...

I you find somewhere new AY3-8910 PSG chips, please tell me. I am collecting a huge amount of the MSX programmable chips in order to produce a compact MSX. At the moment I have 100 new Z80 processors. Still looking for PSG and VDP (TMS9928, in fact).

Any suggestions? Anyone?

Do you have the same problem with the psg sound if you don't have the Salamander cartridge inserted? I remember the Goldstart not being compatible with the scc (dunno what the exact problem was).

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wait, if is a y-3-8910 the chip got 3 pin out, one for each channel, and are soldered in the same print line to mix the sound, so, ¿how can 3 outputs lines broken at the same time? i think the PSG not got nothing wrong, i think some resistor after the mix with PPI click... or maybe a transistor...

That's exactly what I'm hoping to be the case, but I can't trace much of the audio circuitry, and frankly, it's not in my area of expertise. I will try to measure directly on the PSG output pins, though.

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Do you have the same problem with the psg sound if you don't have the Salamander cartridge inserted? I remember the Goldstart not being compatible with the scc (dunno what the exact problem was).

I only got hold of the Salamander cartridge yesterday, and used it for testing purposes. The PSG sound is just as dead with as without cartridge. Does Salamander use the PSG for anything, such as sound effects?

Maybe the service manual might help:

http://www.funet.fi/pub/msx/mirrors/hanso/service_manuals/goldstarfc200sm.pdf

I know the GoldStar FC-200 the SCC/PSG balance isn't correct. The PSG is louder. What you should do is solder a resistor with a lower value over the existing one (can't remember which resistor it is exactly, but with the service manual it should be a fairly simple to track the right one). I think the whole procedure was published in one of the MSX-Gids issues back then. It's the first time I hear the PSG sound is softer.

The MSX Gids article (dutch) on the Goldstar FC200 audio volume adjustment is online at http://www.hansotten.com - MSX Books and Magazines - MSX Gids.
The article is written by Piet and Jeroen Staphorsius in MSX Gids 23 juli/august 1989.


In english: see the figure in page 1, find the 10K resistors between the cartridgeslot and the audio opamp IC, solder a 1200 ohm resistor on top of the 10K resistor near the opamp.

This makes the sound of the SCC louder.