Re: Aw: JU570-2 caps and fix

Hi All!,


Having fixed 3 JU570-2 drives and still having 3 faulty ones left ;-), 
well... I might say I'm getting worried about a little detail.

Let me explain... The PCB of the JU570-2 appears to be some FR2 based, 
cheap, single sided board. FR2 is AFAIK a porous material. The 
observable nature of the corrosion (which always seem to happen without 
any noticeable marks of leak on the solder side) seems to suggest that 
corrosion is done by acid adsorbed by the PCB (which eventually seeps 
through to the solder side of the board).

(This is IMHO very different from the Amiga, and other equipment 
affected by capacitor leak... FR4 and similar glass fibre + epoxy based 
PCBs are generally not porous, they don't absorb liquids. That means 
that a good cleaning + oxide removal as needed + applying some acryllic 
paint or solder resistant lac generally prevents further harms to the 
PCB traces.)

Any ideas and/or experiences? I've made an attempt to neutralize the 
acid remnants using sodium carbonate solution, but I'm getting less 
convinced that that's going to work in the medium term. And I'd hate to 
find out later that the drives gave up despite the work invested (and 
anyway...).


Best regards,


Levente


On 2015-07-22 09:36, HÁRSFALVI Levente wrote:
> Hi!,
>
>
> On 2015-07-21 09:34, Nicolas Welte wrote:
>> I did exactly that, and it works fine :) I had some 10µF ceramic SMD
>> caps left over from Amiga repairs. I'm not sure about the voltage
>> rating which I used, though.
>
> Thanks :-), I ordered the caps yesterday and will make an attempt to fix
> the drives this week. (I'll probably have to deal with the machine first
> so that I'd have something to test the drives with.)
>
>> I think I did the same when I repaired my MSD-SD2 drive, which also
>> suffered from leaking electrolytics. This one doesn't work 100% yet,
>> because the amplifier board in one of the drives had some more severe
>> damage, and after the repair it reads disks, but writing won't work yet.
>
> My worst such experience so far has been the internal drive of my A600
> (a Panasonic JU-253). I managed to revive the unit, but I spent lots of
> time finding all the corroded traces and rewiring everything in such
> small space. The result doesn't really look nice, either ;-), but it at
> least works.
>
>
> Best regards,
>
>
> Levente
>
>
>        Message was sent through the cbm-hackers mailing list
>


       Message was sent through the cbm-hackers mailing list