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#89369 - 19/04/2002 15:30 Problem when powered from AC adapter
beaker
addict

Registered: 19/08/2000
Posts: 588
Loc: England
I've got a problem I'm hoping someone (like Hugo ;-)) can help me with. Sorry if it's a bit long winded.
The power socket on my Empeg MK2 has been getting looser lately and it's been getting more difficult to actually get the unit to power up. It felt as though the spring contact was losing some of it's erm.. spring!! So I thought I'd attempt to bend the contact back a bit to improve it. I couldn't do anything through the opening so I thought that maybe if I unsoldered it from the mainboard I might be able to get to it from underneath. I unsoldered it but I still couldn't get to the spring contact. I did notice that the central pin was a bit off-centre so I gently coaxed it back to where it should be and the plug from the AC adapter certainly felt a much better fit. I soldered it back in and reassembled the player and everything powered up perfectly. I wiggled the plug and it was like new :-) I checked that it still powered up ok in the car (which it did) and congratulated myself on a job well done. On the drive into work this morning everything was working just as it should be but when I plugged it in on my desk it wouldn't power up at all, no matter how much I fiddled with the plug. I took it apart again to see if I could see anything obvious but without knowing the track layout I couldn't do much. Being a multilayer board you can't follow the tracks. I found two square pads on the board, one with "DC in" marked next to it. One of these was certainly directly connected to the -ve terminal of the socket, I guessed the other one should be connected to the +ve so I put a link wire between the pad and the end contact on the socket and crossed my fingers. I plugged it in and it powered up. Yippee I thought, Oh... it thinks it's in the car. Bugger. So this is the current situation: it thinks it's always in the car. This is the opposite problem to the one Hugo fixed for me once. That turned out to be a broken track from the power socket. Can anyone (ie Hugo) point me to where the problem might be. I expect I've put the link in the wrong place. If you can give me some info on continuity checks etc I would be most grateful.

TIA
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Marcus 32 gig MKII (various colours) & 30gig MKIIa

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#89370 - 20/04/2002 08:30 Re: Problem when powered from AC adapter [Re: beaker]
tms13
old hand

Registered: 30/07/2001
Posts: 1115
Loc: Lochcarron and Edinburgh
I'm not Hugo, but I can tell you that you've solved half the problem if it powers up but thinks it's in the car. The power socket has another connection that you didn't follow; that's the little switch that the player reads to know it's on AC. I'm not sure how the switch is connected (is it normally open or closed? is it connected to +ve or ground?) You'll need someone who knows the Empeg PCB to tell you where else this appears on the main board, I'm afraid. Once you've found it, you should be able to simulate inserting the plug.

Hmm, you could try inserting the plug (either the real one, or the right size plug with no power), and if the switch is working, this might fix your problem. Worth a try, and I don't think it can hurt.

Also, you say that Hugo fixed a broken track to your socket - was that the track that's connected to the switch? Probably, given that it was to fix the "always-at-home" symptom. So that might be a clue as to which track to look at.

Hope this is at least some help until the Empeg guys are here again.

BTW beaker - please break your text into paragraphs - it's hard to read in the stream-of-consciousness style...
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030103016 (80GB Mk2a, blue)
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#89371 - 20/04/2002 10:05 Re: Problem when powered from AC adapter [Re: tms13]
beaker
addict

Registered: 19/08/2000
Posts: 588
Loc: England
Yeah, sorry about the lack of paragraphs. I'm usually much better at it than this. I was a bit panicky that's all.

The switch you mention is normally closed and allows 12v to be detected if it's being powered in the car. When the plug is inserted it breaks the contact and 12v doesn't get through to whatever is responsible for detecting it (I'm pretty sure this is how it works, I'm sure Hugo will correct me if I'm wrong). As you say, I'm half way there with the link I've put in but I've obviously put it in the wrong place for full functionality.

I thought about doing some side by side tests with my Rio MK2a but they've changed the PCB layout in this area so that's a dead end. I'm going to have another look at it tonight to see if I can get a proper fix.

The track that Hugo fixed for me was the one that leads from this switched terminal on the socket to the bit that senses whether it's in the car or not. My biggest problem is that most of the tracks are hidden within the PCB and aren't on the surface at all. This makes it impossible to trace anything without either an X-ray machine or a circuit diagram.

I've also noticed that (contrary to my earlier beliefs) that since I've put the link in it isn't working correctly in the car. It ignores the ignition switch position. I'm sure it didn't do this when I tested it last night .

Thanks for your help
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Marcus 32 gig MKII (various colours) & 30gig MKIIa

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#89372 - 20/04/2002 15:27 Re: Problem when powered from AC adapter [Re: beaker]
beaker
addict

Registered: 19/08/2000
Posts: 588
Loc: England
Hmmm... just removed the link and it still thinks it's in the car. I'll continue playing with it and see what happens.
_________________________
Marcus 32 gig MKII (various colours) & 30gig MKIIa

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#89373 - 25/04/2002 15:05 Re: Problem when powered from AC adapter [Re: beaker]
beaker
addict

Registered: 19/08/2000
Posts: 588
Loc: England
ok I've put everything back how it was and it won't power from the AC adapter but works correctly in the car. I think I'm gonna have to talk to support and get them to fix it (at a price of course ). At least I've got my spare.
_________________________
Marcus 32 gig MKII (various colours) & 30gig MKIIa

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