"You also must know you can't heard SCC music without a KB7 as "sound in" is not wired in the PV16
PV7, PV16, MX10 and MX101 are definitively collectors machines and not users machines !"
Do you know if soldering the missing lines to the cart connector will fix that. It seems they just left out the power and ground.
Yes you juste need to wire cart connector pin49 to KB7 connector's sound in.
Don't know where it is in PV7/PV16 but you can look at MX101 connector :
You want to mix it into the audio path somewhere with a resistor, no?
Is pinout of the bus extension same for all Casio MSXs?
I have some other questions: Casio PV-7 have 8kB in slot 0. How does that 8kB expansion or the expansion unit do to add the extra 8KB? These seem add the extra 8 KB in the same slot, and 8kB RAM of expansion unit seems ignored on Casio PV-16. Is the signal /SLTSL1 present in the slot cartridge and extension slot? If 8kB expansion is used at same time expansion unit, it causes conflict?
Werner Kai had fix the Sound In of my PV-7. AFAIK it only needs to soldering an resistor to have the sound working.
I found this tip on a Japanese site.
https://sions-papa.blogspot.jp/2014/08/msx-pv-7pv-161984198x...
A resistor is connected between PSG and the PIN 49 of cartridge slot but the value is not provided.
Since memory is selected in 16K pages, I think the 8K expansion is really just 16K of memory that fully replaces the built-in 8K.
I don't think because the KB-7 extension unit has only 8K inside (we can see it on board picture) and Casio have also released a Ram cartridge of 16K. The slot cartridge 1 probably use MERQ pin or a reserved pin for /SLTSL0 signal.
Edit:
You are right the cartridge have 16K RAM!
https://electrelic.com/electrelic/node/578
The reserved pin 16 seems to be used.
Finally Casio's expansion RAM OR-208 is a ordinary 16kB RAM expansion. The only difference with a standard 16kB Ram is the used bank that is C000h~FFFFh instead of the usual 8000h~7FFFh. The reserved pin 16 is not used.
Casio made a stupid choice to put 8kB in expansion unit. This RAM is more embarrassing than beneficial. It doesn't cause conflict with the OR-208 expansion but it forces the Bios to select RAM in slot 0 and It increases the price of expansion unit. Now I ask how these 8Ko do not conflict with the PV-16.
Well my 1024k memory unit arrived today, along with the cassette cable. Is there any good .cas program I can use to test the memory to make sure it's working?
Just found this as well on that page. The pv-16 will work with the scc stock, no mods.
"PV - 16 has a look that looks exactly like PV - 7, key touch etc does not change,
It is generally recognized that the memory is 16K, but it has been improved.
Extended sound sources such as SCC will ring without modifications ヽ ('ー `) ノ"
How’s it faring? Did you manage to get some stuff running? Did you receive the SD-512 yet?