Amstrad 3in disc drive troubleshooting
jules.richardson99 at gmail.com
Sun Nov 7 16:19:00 CST 2010
Tony Duell wrote:
>> On 06/11/10 20:03, Tony Duell wrote:
>>> Aha...This remionds me ao a character I saw at a couple of radio rallies
>>> many yearsa ago. He had a pile of working hard drives. And another pile
>>> of ''untensted' hard drives. Hmmm...
>> Read as: "I've tested all of these, but I'm selling the broken ones as
> I suspect, and suspected at the time, that you areperfectly correct :-)
> Before we get another flamewar, I will point out that just about every
> seller I've dealt with at radio rallies has been extremely honest. If
> something doesn't work, they say so. If it's missing important parts,
> they say that too.
I get a bit fanatical about testing anything that I'm parting with - I don't
like the idea of the recipient finding a problem that I could have found
myself and told them about. That's always meant I've had a pile of
"extensively tested" stuff, and a pile of "untested because I haven't had the
I suppose it's not impossible to encounter that situation at a radio rally,
car boot sale etc. although I must admit that it's tempting (as a buyer) to
merge the sold-as-seen and I'm-going-to-get-screwed categories :-)
> Ah, my multimeter lives on the workbench.
Mine's always bouncing between house, workshop and garage - I'm rapidly coming
to the conclusion that I need three of everything :-(
>> I'm seeing around 2V on all three pins of the head -- 'top', 'bottom'
>> and the centre tap. If I switch to AC coupling, 200mV/div, I see what
>> looks like a very noisy sine wave on the centre tap, and then the coils
> Trhis is for the selected head? That can't be right!~~~~~~~~~~~~~~~~~~~~
The behavior should presumably be pretty much the same for a 3.5" or 5.25"
drive (depending on media coercivity - I don't recall what 3" is now); maybe
it's worthwhile Phil sanity-checking observed readings against a drive that he
does have around, if he doesn't have a known-good 3" drive handy?
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