Search found 403 matches

by hlide
Mon Jul 06, 2020 7:29 pm
Forum: Other
Topic: MZ 700 - detect PAL/NTSC
Replies: 18
Views: 3873

Re: MZ 700 - detect PAL/NTSC

I now try to count VTOTAL and VBLANK to check if VDISPLAY (= VTOTAL-VBLANK) equals to 200. Note that the usual values are: Pixel PAL NTSC VDISP 200 200 VBLANK 112 62 VTOTAL 312 262 It seems BLANK is only output when sync is normal (not long or short) so our VTOTAL and VBLANK are missing the lines wh...
by hlide
Sun Jul 05, 2020 9:11 pm
Forum: Other
Topic: MZ 700 - detect PAL/NTSC
Replies: 18
Views: 3873

Re: MZ 700 - detect PAL/NTSC

I'm starting thinking that 306 may be the part when /HSYNC is normal and we really got BLANK.

If you look at that picture:
pal_tv_diagram_non_interlace.jpg
pal_tv_diagram_non_interlace.jpg (38.28 KiB) Viewed 101 times
You can see some lines where /SYNC has different values (three here). From the service manual, /HSY is around 4 µS when we get /HBLK and BLNK.
by hlide
Sun Jul 05, 2020 7:53 pm
Forum: Other
Topic: MZ 700 - detect PAL/NTSC
Replies: 18
Views: 3873

Re: MZ 700 - detect PAL/NTSC

It looks as if the way to set/read the two bytes of the counter #2 is giving trouble. So I decided for the timer #2 to count 2 BLNK instead of 1 so I can keep the counter in a byte. I got 306 for mz800emu and 308 for EmuZ-700 PAL. And... I got 306 on my stock MZ-700. Now where did my missing 4-6 lin...
by hlide
Sun Jul 05, 2020 7:19 pm
Forum: Other
Topic: MZ 700 - detect PAL/NTSC
Replies: 18
Views: 3873

Re: MZ 700 - detect PAL/NTSC

And on a stock MZ-700, I have the same result as mz800emu... Gosh!
by hlide
Sun Jul 05, 2020 6:55 pm
Forum: Other
Topic: MZ 700 - detect PAL/NTSC
Replies: 18
Views: 3873

Re: MZ 700 - detect PAL/NTSC

@Jo Even I coded a VSYNC CHECKER (fully assembly code) to use the timer #2 to count BLNK and so to determine how many lines between frames. Here is what I got with EmuZ-700 NTSC (262 lines): 2020-07-05_20-52-02.png And here is what I got with EmuZ-700 PAL (312 lines): 2020-07-05_20-51-56.png So I ha...
by hlide
Tue Jun 16, 2020 1:34 pm
Forum: Hardware
Topic: MZ 80K repair project
Replies: 23
Views: 983

Re: MZ 80K repair project

Sorry the previous one is WITHOUT 16 digital signals. The right one with 16 digital signals is https://www.amazon.fr/Hantek-6022BE-Osc ... =hi&sr=1-4
by hlide
Tue Jun 16, 2020 1:24 pm
Forum: Hardware
Topic: MZ 80K repair project
Replies: 23
Views: 983

Re: MZ 80K repair project

I have this one ; https://www.amazon.fr/Hantek-oscilloscope-stockage-num%C3%A9rique-Oscilloscope/dp/B01M74UKKC/ref=sr_1_5?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=hantek+usb+6022BL&qid=1592313700&sr=8-5 You can have up to two analogical signals and up to 16 digital signals record...
by hlide
Sat Jun 13, 2020 4:23 pm
Forum: Hardware
Topic: MZ 80K repair project
Replies: 23
Views: 983

Re: MZ 80K repair project

Sorry, that's beyond my skills.
by hlide
Thu Jun 11, 2020 10:44 am
Forum: Hardware
Topic: MZ 80K repair project
Replies: 23
Views: 983

Re: MZ 80K repair project

Gortho wrote:
Wed Jun 10, 2020 9:28 pm
*edit*
And +12V rail is used only in display unit. So you might have to look for shorts there.
Nope, DRAM chips DO also use +12V as -5V as well.

I know it because I had to replace them on my MZ80 K.
mz80kdram.jpg
mz80kdram.jpg (72.29 KiB) Viewed 299 times
by hlide
Thu Jun 11, 2020 9:17 am
Forum: Hardware
Topic: MZ 80K repair project
Replies: 23
Views: 983

Re: MZ 80K repair project

And F401 was probably burnt before your power it. Did you check it properly beforehand?

My assumption is F401 blew when the motherboard was connected and this F401 probably saved you video circuit at this moment (let's hope!).