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Portable - two steps forward one back


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58 minutes ago, at0z said:

So P37 always showing 2.75v, when power first connected, during PMGR restart buttons held and after reset.

 

Trying a buzz out is interesting - the schematics for Q10,11,13 appear to show all three legs connected but on my board the middle leg is clipped in each case. No buzz on any pins. I did get a buzz on J21. So not sure if the schematic is "wrong" or I need more coffee...or both. But if I'm getting voltage on that pin, does that mean it doesn't matter ?

FYI, on those transistors, the drain connected to the board is on the 'top' side, opposite the pins.

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46 minutes ago, at0z said:

OK, some coffee onboard. Apologies if this is a dumb question but is this schematic to component mapping correct ?  I also understand my previous question was backwards now - the PMGR *is* the source...

 

 

10887460_Capto_Capture2020-10-28_10-51-26_AM.thumb.jpg.c9447d306e6a1abad5f766f306bf04f1.jpg

 

How recent is this picture? those caps are old and bad. 

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I knew I should have added the disclaimer "this was a before shot for example use only".

 

But I did screw up my pin numbering on the PMGR chip so the ACTUAL reading on pin 37 is a more healthy (?) 5.17v and from there to the major players (GLUs and VIDEO and edge connectors and Q10/11/12) we do ring out. So at least it appears the roads are open.

 

Now I don't know if it was a trick of the light, but I thought I saw out the corner of my eye a flicker on the power draw from the lab supply at random, sometimes I think up to 400mA. Of course if I stare at it, it doesn't happen. I'll do some exploring of the board with my fingers, maybe something is a dry joint...

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13 minutes ago, techknight said:

SYS_PWR has to be pulled to 0v for the system to come up. This is the responsibility of the PMGR. 

 

Chances are, the PMGR is bad. ive used up all my spare PMGRs on parts boards, thats how often they go bad. 

Good lord, I wonder if we should be running these machines at all....

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9 minutes ago, desertrout said:

Good lord, I wonder if we should be running these machines at all....

Thanks techknight for the second opinions on the PMGR. I have a dream there is an Indiana Jones warehouse with dusty crates crammed with excess Apple components inventory from when the Portable production line was shut down. And then I woke up screaming. 
 

Apart from obvious voltage abuse, do they just have self destructive tendencies?

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32 minutes ago, techknight said:

SYS_PWR has to be pulled to 0v for the system to come up. This is the responsibility of the PMGR. 

 

Chances are, the PMGR is bad. ive used up all my spare PMGRs on parts boards, thats how often they go bad. 

Does something external to the PMGR initiate that drop ? I guess we need an Evil Genius to reverse engineer that custom chip...

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14 minutes ago, at0z said:


interesting read, wonder if the PMU in the PB100 could be substituted...

Possibly, I dont know though. I am going to assume the PMU in the PB100 probably has differences because Sony re-engineered the entire power circuit even though at heart, its still a Portable. 

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Right, after reading further it likely carried different firmware. But if you could pull the code out out of a Portable you might be able to flash it back into a PB 100 PMU. Wait, I’m dreaming again aren’t I ....

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Well it’s a funny old game where a measure of success is a chime and a Sad Mac code compared to dead silence. But I'll take that as a half step forward(ish).

 

So Mr 360alaska kindly offered a PMGR chip from one of his PB100 boards and that arrived yesterday. I swapped it out for the presumed dead one (after some discussion about part number interchangeability) and fired up the power full of anticipation but silence reigned and the power draw on the lab supply was zero. Couple of PMGR reset button holds and still nothing. Sad Mac Face.

 

Coincidentally my digikey parts order came in too and in that were some replacement 74AC02/10/157 based on techknight's comments in another thread. I had not been able to determine a thermal issue with any of these using fingers or IR camera but I figured cheap as chips test so swapped them out. Power up board, nothing, no power draw, more Sad Mac Face.

 

OK, maybe the PB100 isn't compatible or something, let's put back the original PMGR chip. Powered it up and I see current draw from the supply. Reset the PMGR, and hit the keyboard. CHIME. Then Sad Chime. Looked at the display to see if it was the old 00003 code as before but new one - 0014 with subcode CD38. Which according to my list says PMGR unable to turn all the power on to the board, and the CD38 suggests a handshaking communication problem...

 

Of course if I can get past this, I might still be back at the Bad RAM 0003 code, but for now at least something is alive. You got to take those small wins....

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18 hours ago, at0z said:

Well it’s a funny old game where a measure of success is a chime and a Sad Mac code compared to dead silence. But I'll take that as a half step forward(ish).

 

So Mr 360alaska kindly offered a PMGR chip from one of his PB100 boards and that arrived yesterday. I swapped it out for the presumed dead one (after some discussion about part number interchangeability) and fired up the power full of anticipation but silence reigned and the power draw on the lab supply was zero. Couple of PMGR reset button holds and still nothing. Sad Mac Face.

 

Coincidentally my digikey parts order came in too and in that were some replacement 74AC02/10/157 based on techknight's comments in another thread. I had not been able to determine a thermal issue with any of these using fingers or IR camera but I figured cheap as chips test so swapped them out. Power up board, nothing, no power draw, more Sad Mac Face.

 

OK, maybe the PB100 isn't compatible or something, let's put back the original PMGR chip. Powered it up and I see current draw from the supply. Reset the PMGR, and hit the keyboard. CHIME. Then Sad Chime. Looked at the display to see if it was the old 00003 code as before but new one - 0014 with subcode CD38. Which according to my list says PMGR unable to turn all the power on to the board, and the CD38 suggests a handshaking communication problem...

 

Of course if I can get past this, I might still be back at the Bad RAM 0003 code, but for now at least something is alive. You got to take those small wins....

 

you have bad traces at the PMGR still. the VIA is coupled with the PMGR so the machine can communicate with it. if this nexus is broken, you get these CD36/CD38 errors. 

 

Thats probably why when you remove the chip, and then reinstalled the original again, it started working. theres something bad in that section of the board electrical connection wise. Plain and simple. 

 

Then again, I cant see your re-work job so you could have issues with that still as well. like some pins that arnt soldered properly or connected. 

Edited by techknight
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I admit I did remove the VIA to look for anything amiss underneath and replaced it. I did have an open on VIA TEST between PMGR and VIA but fixed that. On the PMGR, I have a missing pad on P20 but according to my schematic that doesn't lead anywhere so I ignored it (tell me off I missed something). Here is an iPhone shot of the board as I don't have a camera on the scope. I have not cleaned up the tacky flux at this point. I also discovered my "Amtech" may be a fake but still reviewing that with eBay/Amazon.

 

Is it possible to drag solder the VIA successfully or is it a case of resorting to solder paste ? I cont tested the PMGR pins to their corresponding pads and all beeped out (apart from 20) so I believe they are good. I will do the same with the VIA. After restoring the VIA TEST I still get the same codes.

 

IMG_0019.thumb.jpeg.a8ebd7d4d6af94d18fbd257c6eaa99ed.jpeg

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For those still following along at home, I pin/pad tested the VIA chip and found a few open where the solder may not have fully flowed. Changed to a Rosin flux pen instead of the tacky gel flux which I kind of prefer and fixed the opens. I had also pulled the SWIM chip so I went and tested that too, all good.

 

Fingers crossed, breath bated, power on. 400mA draw and a chime, longer pause then my original 0003 code is back. I guess I need to order some RAM chips to swap out unless someone has an idea how to narrow it down.  Anybody recommend part numbers from Mouser or Digi-Key?
 

But at least I’m back a square one with a recapped board that powers on...

Edited by at0z
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35 minutes ago, 360alaska said:

Pretty easy, all of the pins except 1 should ohm out to the chip in front of it.


Could you give an example? What orientation is “in front “ ? Sorry need a little added color...

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42 minutes ago, techknight said:

You probably need to remove the RAM ICs and inspect the traces/vias leading in and out of them, or verify against the schematics. I have found a few open connections to the RAM before, as well as bad RAM. 


That would save some spendy- in your experience is it a case the RAM itself is usually okay?

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