Arcam Alpha Plus cracking

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#42
If you are freezing just the chip carefully and the voltages aren't over the max ratings then that's pretty conclusive.

Many old players used the TDA1541 which is a dual (stereo) DAC so one channel affected or affected more than another would be normal.

You want something like an old Philips (CD150 but check !! etc)as a donor... or maybe start a new thread asking if anyone has one. These IC's have been out of production for years.
 
#43
Hi - the diyaudio thread is http://www.diyaudio.com/forums/digital-source/64043-tda1541a-distortion-problems.html if you follow the link on the first post the detail is right at the bottom.

I think your player has the TDA1541A which are a bit tricky to come by, depending on the implementation you may be able to swap it for the non-A version. I have a working non-a here and I'd be happy to post it over if you can find out if it's a straight swap. I suspect it won't be though as you also have the later /b version of the filter (nothings simple in this hobby!)

As Mooly says, that freeze test is pretty conclusive though. You can pick up a replacement TDA1541A on ebay if your careful or, if you want a doner player (it may even cost less and you know you getting a genuine part) then check this list before hand to make sure you get the right DAC chip. Players with these chips go for anything from £20-£30 up to silly money but you might get a bargain with a sticky drawer or read problems. A doner also has the added benefit of being a resource for other bits and pieces if it turns out not to be the DAC chip!

Hope this helps
 
#44
Mooly said:
If you are freezing just the chip carefully and the voltages aren't over the max ratings then that's pretty conclusive.

Many old players used the TDA1541 which is a dual (stereo) DAC so one channel affected or affected more than another would be normal.

You want something like an old Philips (CD150 but check !! etc)as a donor... or maybe start a new thread asking if anyone has one. These IC's have been out of production for years.
Click to expand...

josha said:
Hi - the diyaudio thread is http://www.diyaudio.com/forums/digital-source/64043-tda1541a-distortion-problems.html if you follow the link on the first post the detail is right at the bottom.

I think your player has the TDA1541A which are a bit tricky to come by, depending on the implementation you may be able to swap it for the non-A version. I have a working non-a here and I'd be happy to post it over if you can find out if it's a straight swap. I suspect it won't be though as you also have the later /b version of the filter (nothings simple in this hobby!)

As Mooly says, that freeze test is pretty conclusive though. You can pick up a replacement TDA1541A on ebay if your careful or, if you want a doner player (it may even cost less and you know you getting a genuine part) then check this list before hand to make sure you get the right DAC chip. Players with these chips go for anything from £20-£30 up to silly money but you might get a bargain with a sticky drawer or read problems. A doner also has the added benefit of being a resource for other bits and pieces if it turns out not to be the DAC chip!

Hope this helps
Click to expand...

Many thanks you two (and others who replied)

I will check that I haven't chilled any caps whilst cooling the chip but I was VERY careful to get only a tiny bit on the chip and the impact was instant so pretty sure now that's what the cause was. Just odd that it started failing as soon as I'd re-installed the Dual t/table and Marantz tape deck into the system - must have been a fluke of timing

The search begins! The list of players with the TDA chip is really useful
 
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#48
Mooly said:
As far as I know, the different versions were "selected" devices from the normal production run. I think any would work OK in any player.
Yes any TDA1541A is identical.

Another list here, although check accuracy before getting anything.
List of players with 1541 - pink fish media
Click to expand...

interesting the Philips CD160 doesn't appear on this list but it does on the other one (the specs state it has a 1541) - so you are right to be wary
 
#49
As long as it is a 1541A, as opposed to the 1541 it should be fine, you also stand a much better chance of getting the genuine article by buying a complete player. Funnily enough the 1541 (non-A) I have is from a CD160! The A version is revised but does have at least one fundamental difference that makes interchanging them hazerdous! Further derivatives of the A version (R1, S1 & Crowns) as mooly says were selected on performance but are fully interchangeable.
 
#57
I've used a solder sucker with some success but you have to be careful not to lift the pads, should be ok for a 'one off' job though. They also drop a lot of powdery solder so a good 'blow' is required around the board afterward!

Plated vias are a bit fiddly - I add a little solder to the iron first and this helps it flow.
 
#58
Are they plated vias ? I was assuming single sided for the IC's

If they are plated vias then that's not easy as Jon mentions and particularly if you are unused to working with them.

If the IC to be discarded has vias then just snipping the legs close to the IC and heating and pulling the remains out with tweezers works well. Then use a bit of stainless wire to run through the hole while applying the iron.

You can't really do that for the donor IC though unless you tag a wire to each cut off leg. If you really are stuck them that is a workable option though.

It can be done very neatly if you use solid wire such as resistor legs 🙂
 
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