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#294528 - 05/03/2007 22:08 Removing a PCATS memory expansion board..
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Patrick's memory expansion boards can be great, but they are quite difficult to install perfectly, and even the best installers sometimes have trouble.

This can result in a player with an installed board which doesn't actually work reliably. When that happens, it is often best to just leave the board in-situ, and flip all four bank enable switches off, effectively disabling the board.

The alternative, desoldering the board and removing it, bears a high risk of destruction to the player mainboard.

I have now removed three memory boards. The first time was on one of my own, and I got lucky in that it removed just fine with no damage.

The second time I removed one (same board, actually) resulted in much destruction of test pads and attached traces, requiring a couple of hours of work tracing signals and solding in replacement jumpers. That player has been in good health ever since, though.

The third time was this evening. I began by solder sucking all of the connections, and then gently pried up the VCC, SCL, and GND connections (while heating them with a soldering iron), one at a time to release the bulk of the memory board. So far so good.

Now for the two big groups of test pads.. this is where all of the damage happens. I started heating/prying, but then got a clue and stopped.

Down to the workshop, bore a 1.3" hole in a scrap of plywood, place hole over the test pads area, masking off the rest of the player & memory board. Apply heat gun on "high", and wait a few seconds.

The memory board promptly fell off, with very minimal damage to the pads -- probably all inflicted during installation and/or the inital prying beforehand.

The player boots up and works perfectly, and the memory board looks like new.

So.. if you ever have to do this, Don't Do It !!!. Send it to me instead.

Cheers!

Mark


Edited by mlord (05/03/2007 22:11)

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#294529 - 05/03/2007 22:24 Re: Removing a PCATS memory expansion board.. [Re: mlord]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
And here's a photo of the basic idea.
The white thing is a slim pry bar that I used to separate the two once the solder had melted.



Of course, a better approach would be to have a hot-air desoldering machine.
But not many home labs are likely to have one of those!

Cheers


Attachments
295304-a.jpg (94 downloads)



Edited by mlord (05/03/2007 22:25)

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#294530 - 06/03/2007 00:54 Re: Removing a PCATS memory expansion board.. [Re: mlord]
maczrool
pooh-bah

Registered: 13/01/2002
Posts: 1649
Loc: Louisiana, USA
Hey Mark,

Excellent suggestion in lieu of a proper hot air setup. I've run into one sitution where the memory board would not work at all, but luckily the switches did the trick and at least got the Empeg booting again. In the end I just left the board in place and did the much more reliable memory stack to 32 MB.

Have you had any thoughts to just doing continuity tests and jumpering the ones that aren't connected? I tried this, but it didn't work. Perhaps the jumper wires added too much capacitance to the lines. I'm not sure.

Stu
_________________________
If you want it to break, buy Sony!

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#294531 - 06/03/2007 01:33 Re: Removing a PCATS memory expansion board.. [Re: maczrool]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Quote:
ave you had any thoughts to just doing continuity tests and jumpering the ones that aren't connected? I tried this, but it didn't work.


Tell me about it..

On the first system I did this with (one of my own), the impression I got was that the timing was very very tight -- longer wire added enough nano-seconds (or capacitance?) to make things just not work.

Of course, now I have a logic analyzer, which could have been very handy way back then to let me see the (more or less) exact timings.

Cheers

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#294532 - 06/03/2007 16:05 Re: Removing a PCATS memory expansion board.. [Re: mlord]
Waterman981
old hand

Registered: 14/02/2002
Posts: 804
Loc: Salt Lake City, UT
Quote:
So.. if you ever have to do this, Don't Do It !!!. Send it to me instead.

I fully agree! If you need to remove it send it to Mark! I ripped off so many pads, and had a bunch of jumpers I had to install. My empeg is still going strong though!
_________________________
-Michael

#040103696 on a shelf
Mk2a - 90 GB - Red - Illuminated buttons

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#294533 - 04/04/2007 11:23 Re: Removing a PCATS memory expansion board.. [Re: Waterman981]
Flawed
stranger

Registered: 15/02/2002
Posts: 53
Are the boards still available or are they really not recommended?

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#294534 - 08/04/2007 18:06 Re: Removing a PCATS memory expansion board.. [Re: Flawed]
FireFox31
pooh-bah

Registered: 19/09/2002
Posts: 2494
Loc: East Coast, USA
Mine's available. I don't know if it's in operating condition or not. I've been considering asking Patrick if he'll look at it and repair if necessary.
_________________________
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FireFox31
110gig MKIIa (30+80), Eutronix lights, 32 meg stacked RAM, Filener orange gel lens, Greenlights Lit Buttons green set

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#294535 - 08/04/2007 18:49 Re: Removing a PCATS memory expansion board.. [Re: FireFox31]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14491
Loc: Canada
Quote:
Mine's available. I don't know if it's in operating condition or not. I've been considering asking Patrick if he'll look at it and repair if necessary.


I think your board is in fine shape.

Cheers

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