HB-F9S v9938 partially dead?

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Van blackmsx

Expert (77)

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26-12-2015, 23:14

flyguille wrote:

Do you have, erratic "syntax i/o error" on correct commands?

Not that I've notice it, but I havent used much basic either. I've mostly trying MSX-DOS, adding programs to the CF and loading them.

Van sd_snatcher

Prophet (3472)

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31-12-2015, 13:56

Get CHKSPD from the GR8BIT site, run it in your machine and post the results here.

Van flyguille

Prophet (3028)

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31-12-2015, 14:11

blackmsx wrote:
flyguille wrote:

Do you have, erratic "syntax i/o error" on correct commands?

Not that I've notice it, but I havent used much basic either. I've mostly trying MSX-DOS, adding programs to the CF and loading them.

I heard from you that you changed some cpu clock crystal? is it right, it is reffering to this machine?.

Van bch

Supporter (3)

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31-12-2015, 20:37

flyguille wrote:

I heard from you that you changed some cpu clock crystal? is it right, it is reffering to this machine?.

No, that wasnt me. I did upgrade the internal RAM to 512k but did not touch the clock crystal.

sd_snatcher wrote:

Get CHKSPD from the GR8BIT site, run it in your machine and post the results here.

CHKSPD outputs:

VDP XTAL: 21.480000
VR RATE: 50.165349

T-CYCLES: 003DBEB9
Z80 CPU SPEED: 4.046521

T-CYCLES DELTA (oscilating between)
-00006A75/24.7 behind
-00006ABF/24.8 behind

Van blackmsx

Expert (77)

afbeelding van blackmsx

01-01-2016, 11:15

bch wrote:
flyguille wrote:

I heard from you that you changed some cpu clock crystal? is it right, it is reffering to this machine?.

No, that wasnt me. I did upgrade the internal RAM to 512k but did not touch the clock crystal.

sd_snatcher wrote:

Get CHKSPD from the GR8BIT site, run it in your machine and post the results here.

CHKSPD outputs:

VDP XTAL: 21.480000
VR RATE: 50.165349

T-CYCLES: 003DBEB9
Z80 CPU SPEED: 4.046521

T-CYCLES DELTA (oscilating between)
-00006A75/24.7 behind
-00006ABF/24.8 behind

Ups, sorry. That was me. I registered in the forum once and I couldnt remember the log in, so I registered once more. Then last night I posted from my desktop PC and it seems it was logged in the old account...

Van sd_snatcher

Prophet (3472)

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01-01-2016, 14:32

Well, as I suspected, the CPU speed in your machine is above normal. This is why MSX1 games are working, while MSX2 software isn't. (MSX1 software have bigger delays built in for the VDP I/O)

Your VDP is fine. The probable cause is that the waitstate of the M1 cycle isn't functional. Try the following checks with a multimeter:

- Check if there's a 1K resistance between the pin-24 (/WAIT) and the pin-11 (Vcc) of the Z80A.
- Check if the pin-38 (/WAIT) of the S1985 is connected to the pin-24 of the Z80A
- Check if the pin-32 (/M1) of the S1985 is connected to the pin-27 (/M1) of the Z80A

Van blackmsx

Expert (77)

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01-01-2016, 16:32

sd_snatcher wrote:

- Check if there's a 1K resistance between the pin-24 (/WAIT) and the pin-11 (Vcc) of the Z80A.
- Check if the pin-38 (/WAIT) of the S1985 is connected to the pin-24 of the Z80A
- Check if the pin-32 (/M1) of the S1985 is connected to the pin-27 (/M1) of the Z80A

Both pins (38 and 32) from the S1985 are connected to the CPU. There is a 1k resistor (R121) connected between CPU pin 24 and VCC but the resistance measures about 700 ohms.

Van blackmsx

Expert (77)

afbeelding van blackmsx

01-01-2016, 21:00

sd_snatcher wrote:

Well, as I suspected, the CPU speed in your machine is above normal. This is why MSX1 games are working, while MSX2 software isn't. (MSX1 software have bigger delays built in for the VDP I/O)

By the way, as far as I can tell I can run software just fine. My problem is characters get scrambled when the screen starts scrolling...

Van Manuel

Ascended (18160)

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01-01-2016, 21:31

4.05MHz is not OK though, sd_snatcher said. Is this measuring program this accurate?

Van blackmsx

Expert (77)

afbeelding van blackmsx

02-01-2016, 00:17

I've tryed CHKSPD.COM on blueMSX and it reports 3.57 mhz, which its the correct speed, right?

4.05 mhz is a lot more indeed, and might be the reason for the problem Im having (and perhaps some I've not noticed)

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