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Andrew96_

JPM system 80 cpu board repair

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I noticed both sellers are from abroad !its not jist china then !

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Trouble is you never know if a UK (or anywhere else) seller has bought a load from China, realised he's bought a pup and then tried to sell them on again.

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I am now looking at another sys 80 board, this one has 3 x 2532 eproms on it, tried the eproms on another board and nope no boot! then looked at them on my dataman programmer, 2 were fine but one was bad pin 24! so suspected earlier in its life it had been put on the board the wrong way round and switched on blowing it up! so today took it into work and looked under the stereoscope into the quartz window!

this was the result!

Image-123.thumb.jpg.5d9d0cd90bfd9b6fe7bc811616d539d9.jpg

you can see the melted 5v power line to the die has melted and formed little round bits of the remaining wire on the ends of the wire! YEP clearly been put in the wrong way round! If this was a very valuable eprom that had not been dumped then it is sill possible to get the data from it once the blown connection is remade! that's the tricky bit!!! But this rom is  for the bin! just thought you all might like to see close up what happens when a eprom is inadvertently put in the wrong way round!

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Great shot and definately gives a good insight into the hazards of putting chips in.the wrong way round !mentioned this the other day funnily enough .thanks for posting andrew.

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cheers! much the same shots but here are some more of the same as different bits are in focus as at that magnification the depth of field is tiny!

Image-1aa.thumb.jpg.1dfc912745564d34d1d2e96afce9a1a0.jpg

Image-1bb.thumb.jpg.072a34432a9e008a028c12269d1a6792.jpg

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As we know Andrew you've managed to patch these wires up before. I remember reading one of your threads when I first started repairing fruity's and I was in total awe!

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48 minutes ago, midibob said:

As we know Andrew you've managed to patch these wires up before. I remember reading one of your threads when I first started repairing fruity's and I was in total awe!

 

That's right Bob, but this is not one  that needs recovering, one of a kind type, so won't be cracking this one open to get at it!

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Plumbers blow torch and a solder pot will soon put this right lol.

Very interesting to see it close up, thanks Andrew.

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that was around 60x zoom I believe on a leica S6, Looking on ebay these stereoscopes go for a lot of money!! just the head goes for £350 up wards to around £600 plus, and one on a stand is £1000 plus even on ebay!

but keeping a eye out on ebay I spotted this Leica stereozoom6 for £100, it appears to come from a jeweler as it has a underneath  light and one on the top ! but at that price I can always not use the under light part! it will be handy for looking at positioning and soldering of smd components! It also looks like it has a extra X2 lens on it and looking it up makes it 128X zoom!! so hopefully it will be good and I can take more pics of the chip really zoomed in!! i wonder if any patterns can be seen on the eprom surface for the 0's and 1's data!!

 

this is what I have arriving this week!

703236190_leicasz6.jpg.a9951193889de31ea69a3690749591ef.jpg

Edited by Andrew96_

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The one drawback with my scope is there's not enough space between the support arm and the lens so you can't get to look at the middle of large boards. Mind you it wasn't designed for that and luckily most batteries on boards are near the edges where the tracks are corroded.

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yeah at work we have them on long arms just for that reason! Like this

csm_Leica_Flexarm_Stand_list_567f55d74b.

but there out of my price range! I was very lucky to get this one so cheap! beggars can't be choosers!

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Mine arrived today! so put another suspected blown rom put in the wrong way round in it's life! sure enough its got the melted internal wire!

IMG_2879.thumb.jpg.933d22947a205568d4a822136777fdce.jpg

bit more zoom on the chip die! can read the numbers on the die! it is better when using eyes rather than a camera phone!

IMG_2881.thumb.jpg.2886417d90df44de3cb360b4c1b16db9.jpg

and finally a smd chip I soldered on (epoch board)

IMG_2883.jpg.8da65f6bdc29aa2dfd909b779defcbda.jpg

this is going to be great in making sure the joints flow good!

bit closer!

IMG_2884.jpg.2c2aa63f4447c9a31a80e7835539b5b5.jpg

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how about this, a old MPU5 board and a surface mount,chip with pins quite close together

IMG_2887.jpg.403756a02655439b2a656bd2791d958c.jpg

an now I can quite clearly see the solder fillets on the chip! this is going to be great for making sure smd chip pins are wetted and making a connection!

IMG_2886.PNG.b011d431d1e99866ca57d7ebcb3eff7f.PNG

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