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Re: Help: Sharp MZ 700 short fuse with video connection

Posted: Mon Jun 06, 2022 3:37 pm
by folkoh
Ok thx, yes I believe the RF box is the suspect. I am going into check mode with oscilloscope next.

Re: Help: Sharp MZ 700 short fuse with video connection

Posted: Tue Jul 05, 2022 10:20 am
by folkoh
Hello,

first sorry for the silence, life happened.

Today I had a look with my cheapo oscilloscope not being an expert this is what I got:

In B/W mode:
MZ700_bw.JPEG
In colour mode:
MZ700_col_low.JPEG
MZ700_col_hi.JPEG
With my little expertise I'd say it doesn't look to dramatic, so I gave it another shot, still shorting out the fuse of 1/3 the house.

So propably the RF Box is to blame, with a power surge when conncected to a monitor. Why, I do not understand.

Soldering directly a Scart avoiding the RF Box.. I have doubts. All I really want is to understand why the power surge is happening.
But I don't and probably won't. So I may just stop the MZ-700 recovery this is a bit beyond my repair capabilities and I do not like to set the house on fire ;-)))

But many thanks for the extensive support and ideas!

Re: Help: Sharp MZ 700 short fuse with video connection

Posted: Tue Jul 05, 2022 7:42 pm
by hlide
You don't need to solder a SCART. Breadboard, resistors and Dupont wires and an Amiga SCART cable and then you can test. It doesn't need to be permanent. The issue is to discover whether your RF box is the culprit.

Re: Help: Sharp MZ 700 short fuse with video connection

Posted: Wed Jul 19, 2023 2:06 pm
by folkoh
Hello,

as said last year, I have stopped on that project. Now I am offering the MZ-731 on ebay. If someone is interested, here is the auction starting at whopping 1€ price tag... may someone with more time and experience give it a new life.

https://www.ebay.de/itm/155673629144

Cheers,

Folko