Date   : Wed, 17 Jun 2015 06:23:09 +0100
From   : mike@... (Michael Howard)
Subject: SJ Research MDFS Wiring Diagram

On 17/06/2015 05:27, Mike Pepper wrote:
>> On 14/06/2015 17:39, J.G.Harston wrote:
>>> Michael Howard wrote:
>>>>    I have 2 x MDFS which I'm trying to resurrect.
>>> ...
>>>>    I'm looking for a wiring diagram/schematics so I can find out what
>>>> should be at C3 on the main PCB. One of the MDFS has nothing there and
>>> The Community have been looking for technical info on the MDFSs for
>>> year.
>>> There was somebody up north who did MDFS repairs and SCSI/parity mods.
>>> Somebody on here may remember who it was, there may be the possibilty he
>>> still has some reference material.
>> I wonder if he has ever been asked if he has any reference material?
>>>    I bought my MDFS from him in 1998,
>>> if I could find my receipt I could tell you who he was.
>>>
>> Well, no worries.
>> If the next time somebody here opens up their MDFS I'd be grateful if
>> they could let me know what is at C3 :)
>>
>> Cheers,
>> Mike.
> If it was a small 2-leaded 'blob', it was probably a tantalum capacitor
> across the power rails. One of tehir failure modes is to go short circuit,
> and since the power supply in the MDFS is quite 'beefy', they can then
> explode or burn away.
>
> If it is such a thing, then it's non critical, and could be replaced with a
> small electrolytic.  A quick check with an Ohm meter will let you know if it
> was across the 5V rail.
>
> Hope this helps
>
Yes, thank you, it does help. What was left did indeed look like a 
'blob'. Something like;

http://uk.farnell.com/avx/tap474k050scs/tantalum-capacitor-0-47uf-50v/dp/1260899

So I guess I could use these, assuming it was across the 5V rail?

Cheers,
Mike.

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