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Dead Sharp MZ80A

T

track18

Experienced Member
Joined
Mar 12, 2009
Messages
51
Location
Hannover, Germany
Hi there,

still not finished (well, actually not even begun) cleaning my PET's keyboard, I today received another baby: My parents-in-law gave me a Sharp MZ80A, which they got from some relatives who were about to dump the machine just before they learned about my interest in vintage computers... Unfortunately, the device seems dead as a dodo -- no lifesign after switching it on (so sound, no picture, no nothing).

I know basically nothing about this kind of machine (grew up with 6502-based computers), but I well remember its cool all-in-one design from the adverts I saw back in the early 80s. I wonder if there's someone around in the forum who is more acquainted with this sort of machine -- and who can tell me the three most frequent causes for MZ80 power failures? (Perhaps its just a burned-out fuse?)

Best regards --

track18
 
Well done.

Yep, the old line-filter rice-paper capacitors. If anything is going to go, it will be them.

Tez
 
track18 said:
Hi everyone,

just wanna let you knot that my new old Sharp is back on line -- two blown fuses, two exploded capacitors and quite some tedious keyboard cleaning later! The whole story is documented at http://www.tcrass.de/computer/retro/sharp_mz_80a/reparatur.html -- in German, though... But maybe the fotos are self-explanatory enough.

Best regerds --
Click to expand...
Another great site; informative and entertaining, too bad it's only in German. As it happens, I do read German so I can appreciate your style; had me chuckling.

And my thanks again to folks like you and Tezza who share your adventures with the rest of us and let us learn from your experiences; it's one thing to get advice which may or may not be correct or relevant, but quite another to read about actual hands-on successes (or even the occasional, hopefully only temporary, failure).

Thanks guys (and gals of course!)
 
ahm said:
Just drop the URL into Google Translate -- it does a pretty good job.
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Of course, but like most great works of literature it's not quite the same as reading it in the original tongue ;-)

Mind you, the translation does add some humour of its own...

BTW, it's probably just my obsolete browser, but does anyone else have the text drop down below the bottom of the index instead of being beside it (where I assume it should be)?
 
Hi everyone,

and thanks for back-slapping, almost made me blush... ;-)

MikeS said:
Another great site; informative and entertaining, too bad it's only in German. As it happens, I do read German so I can appreciate your style; had me chuckling.
Click to expand...

Mike, how come you read German so well? I mean, I'm not exactly cultivating a German textbook style...

<sigh/>Of course I'd love to do an English version of my homepage too (there used to be one, btw, when the site comprised only a handful of sub-pages), but I absolutely don't have the time, and since I'm doing this homepage thing also for people like my parents (so that they can see what their little boy is wasting his time with), I'll have to stick with the German version for the time being.

MikeS said:
Mind you, the translation does add some humour of its own...
Click to expand...

...but I found Google Translate to do a surprisingly good job. At least when compared to the rubbish produced by such tools some ten years ago and when taking into consideration that in this case it had to cope not just with subject-predicate-object sentences.

MikeS said:
BTW, it's probably just my obsolete browser, but does anyone else have the text drop down below the bottom of the index instead of being beside it (where I assume it should be)?
Click to expand...

Now I'm a little confused -- are you talking about Google Translate, the Vintage Computer Forum or my homepage? If you refer to the latter, I better double-check my CSS...

Anyway, the show will go on -- meanwhile I got all the stuff together I need for a) building a PC-to-Sharp-data-recorder interface (according to http://sharpmz.org/index.html) and b) preparing some retr0bright.

All the best --
 
track18 said:
Mike, how come you read German so well? I mean, I'm not exactly cultivating a German textbook style...
Click to expand...
Born and raised in Hamburg till I came to the new world at the tender age of eight.
...but I found Google Translate to do a surprisingly good job. At least when compared to the rubbish produced by such tools some ten years ago and when taking into consideration that in this case it had to cope not just with subject-predicate-object sentences.
Click to expand...
Indeed; I was also surprised by how good it was.

Now I'm a little confused -- are you talking about Google Translate, the Vintage Computer Forum or my homepage? If you refer to the latter, I better double-check my CSS...
Click to expand...
I wouldn't worry too much; time to upgrade my browser (IE 6) anyway, I'll let you know if it still does it.

What happens is that when some of the pages open the text is beside the red coloured legend at the left, but as the page continues to open the text suddenly seems to disappear, leaving a blank space on the right; scrolling down reveals that it has shifted down so that the top of the text is in line with the bottom of the legend.

Anyway, the show will go on -- meanwhile I got all the stuff together I need for a) building a PC-to-Sharp-data-recorder interface (according to http://sharpmz.org/index.html) and b) preparing some retr0bright.

All the best --
Click to expand...
Hmm, my main interest was in the PET blog, but I do have a little Sharp handheld somewhere...
 
Hi everyone,

its amazing how long it takes to get rid of the yellow-ish tint of the Sharp's casing... By now, I've been retr0brighting one side of the casing for almost three days, and there are still some yellow speckles and streaks left, rendering even this treated area noticeably yellower than the (non-stained) inside. Well, perhaps its the combination of a realy highly discoloured piece of plastic with an only 6% H2O2 solution that's responsible for the slow progress. (At least I am using a real UV fluorescent tube and don't have to rely on the sun to shine, which these days still doesn't happen too frequently hereabouts.)

cosam said:
Amazing what a quick run through the dishwasher can do for an old PCB!
Click to expand...

For retr0brighting the casing, I had to dismount many parts, including the data recorder. At this occasion I realised that many of its sub-parts were also covered with dirt and dust, and I keep wondering if I should give it a go in the dishwasher, too. On the other hand, there are not just electronic, but also mechanical parts involved, and I'm not sure if, say, an electric motor would appreciate being soaked with suds. Anyone having had any (good or bad) exprecience on this issue?

MikeS said:
I wouldn't worry too much; time to upgrade my browser (IE 6) anyway, I'll let you know if it still does it.

What happens is that when some of the pages open the text is beside the red coloured legend at the left, but as the page continues to open the text suddenly seems to disappear, leaving a blank space on the right; scrolling down reveals that it has shifted down so that the top of the text is in line with the bottom of the legend.
Click to expand...

O cr*p! I really thought I had sorted out this IE6 issue when doing my web design... Unfortunately there are still so many IE6 users out there that you can't just negelct them... ;-) So back to the text editor -- time permitting!

Best regards --
 
track18 said:
<snip>
O cr*p! I really thought I had sorted out this IE6 issue when doing my web design... Unfortunately there are still so many IE6 users out there that you can't just negelct them... ;-) So back to the text editor -- time permitting!

Best regards --
Click to expand...
Oh, go ahead, neglect us ;-) Every site we visit these days is warning us anyway that we're not going to get its full transcendental experience unless we upgrade.
 
track18 said:
its amazing how long it takes to get rid of the yellow-ish tint of the Sharp's casing... By now, I've been retr0brighting one side of the casing for almost three days, and there are still some yellow speckles and streaks left, rendering even this treated area noticeably yellower than the (non-stained) inside. Well, perhaps its the combination of a realy highly discoloured piece of plastic with an only 6% H2O2 solution that's responsible for the slow progress. (At least I am using a real UV fluorescent tube and don't have to rely on the sun to shine, which these days still doesn't happen too frequently hereabouts.)
Click to expand...

I've found with retrobriting very old, very yellow, cases that there does seem to be a point where no matter how long you keep going, there is no further improvement. I used 6% H2O2 and I found after about 14 hours of exposure to sun it seemed it was as good as it was ever going to get. Some streaking is common too. My RX8800 case for example.

Certainly looks better than it did though.

It would be good to do a long term H2O2 soak, with a pic after each day just to acertain the deyellowing rate drop-off and whether things actually get worse (e.g. streaking) with prolonged exposure to the process. Certainly coloured cases can suffer "bloom" if overcooked.

Tez
 
tezza,

tezza said:
I've found with retrobriting very old, very yellow, cases that there does seem to be a point where no matter how long you keep going, there is no further improvement. I used 6% H2O2 and I found after about 14 hours of exposure to sun it seemed it was as good as it was ever going to get. Some streaking is common too. My RX8800 case for example.

Certainly looks better than it did though.
Click to expand...

no argument about that -- looks great! :) (Of course, I've already read about your 6% experiments before.)

And finally, after 72 hours of almost continuous application of retr0bright gel, the treated area of my Sharp's case looks almost indistinguishable from the non-stained inside. Perhaps my initial retr0bright preparation was to viscous -- two heaped tablespoons of xanthan resulted in some kind of "blob" rather than a gel, so for the last 24 hours I diluted it a littel with water (thereby also reducing the H2O2 concentration, but in some German forum I've read about some guy who successfuly applied only 3% H2O2).

As for the drying out, does anyone know what the glycerol's supposed to be good for? Maybe it is intended to retain at least some moisture? (Anyway, the so-called "science bit" on http://retr0bright.wikispaces.com/ seems somewhat questionable to me... Admittedly, it's been a while since my last lectures in organic and inorganic chemistry, but some things stated on that page I just don't get.)

tezza said:
It would be good to do a long term H2O2 soak, with a pic after each day just to acertain the deyellowing rate drop-off and whether things actually get worse (e.g. streaking) with prolonged exposure to the process.
Click to expand...

You're right, that would have been the scientificly correct way.


Regarding my other question -- no one ever tried dishwashing a tape recorder...?

Regards --
 
track18 said:
Regarding my other question -- no one ever tried dishwashing a tape recorder...?
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I should think it'd be OK if you were doing a complete strip-down and rebuild. Even a gentle cycle is going to have some kind of degreasing effect, but as long as any lubricants are reapplied afterwards I should think you'd be fine. I'd probably avoid electromechanical stuff like motors though, if you can't disassemble them fully. It'd be hard to lubricate them properly and you might also run into problems with deposits being left behind in tight spaces where the water can't flow or drain sufficiently.
 
track18 said:
<snip>
Regarding my other question -- no one ever tried (dish)washing a tape recorder...?

Regards --
Click to expand...
Not intentionally...

You guys are inspiring me to try retr0brighting one of my yellow Hyperions now that the sun is back in the sky; I may be asking you off-list about the latest recipes...
 
Hi,

and thanks for your comments regarding the tape.

cosam said:
I should think it'd be OK if you were doing a complete strip-down and rebuild. Even a gentle cycle is going to have some kind of degreasing effect, but as long as any lubricants are reapplied afterwards I should think you'd be fine. I'd probably avoid electromechanical stuff like motors though, if you can't disassemble them fully. It'd be hard to lubricate them properly and you might also run into problems with deposits being left behind in tight spaces where the water can't flow or drain sufficiently.
Click to expand...

Sounds reasonable -- I'll see if I can dismount the motor (and maybe any belts) and give the remaining parts a go in the dishwasher.

MikeS said:
Not intentionally...
Click to expand...

That makes me wonder how many times you've dishwashed one unintentionally... ;-)

So long (not before Monday -- will be off for the weekend in a minute, rehearsing with the gospel choir im singing in...)
 
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