A600 recapped but now with colour issues

[F0LLETT]

Hi all,

I checked the voltages from transistor to ground, I believe I see the below values.  I am not seeing 2.2volts as mentioned previously anywhere They are all giving the same value.  I also removed the Sony chip, cleaned below it and resoldered it back into place.  Now my screen has gone very dark (I can barely see colours on screen). Now wondering if my Sony chip is actually bad as I seem to have made the picture worse removing and reinstalling the chip.  The other thing I was wondering is if I should also remove the IDE connector as a number of pins on this had gone green.  There maybe capacitor leakage below it.  Any direction appreciated.  I have bought a replacement Sony chip as I shall replace this now anyway.

V pin 1(B) to GND   V pin 1(B) to pin2 E          V pin 1(B) - 2E
Q231   0                     0                                   -5.04
Q232   0                     0                                   -5.04
Q233   0                     0                                   -5.03


Regards

Steve

It should not have gone worse. Unless there is track damage from leakage.
Also, how did you read voltages, as -v is not right. Even if faulty, no way they would all be -v.

[screwtop]

Bear in mind that leaked electrolyte can potentially etch away just the solder mask, making it very easy to inadvertently bridge tracks when recapping. That happened to me with my A600: there was a clicking sound in the audio due to an interrupt line being bridged to AVref. https://www.amigapcb.org/ is super-handy for identifying potential trouble spots. Removing all the leaked electrolyte can be quite difficult, and in severe cases it can end up conductive (as well as corrosive) due to the dissolved copper. Good luck!

[swood123]

I believe you are correct.  I did have a damaged pad but I assumed the pin didnt go anywhere I did check schematic and assumed it was pin 5. I assumed first pin was right next to the indent at bottom left.  On closer inspection and after removing the chip I can see it may actually go to a round contact right below it.  See attached pic.  What are your thoughts on this?


Thanks for your help with this, it's been an interesting learning curve for myself.

Amendment.. I just read Screwtops link, thanks.  The link to the schematics is quite handy but from it it does look like pin5 for the Sony chip doesnt go anywhere... :/

It looks like I may have to do some continuity testing accross the board using the schematics website..



Regards

Steven

[F0LLETT]

I believe you are correct.  I did have a damaged pad but I assumed the pin didnt go anywhere I did check schematic and assumed it was pin 5. I assumed first pin was right next to the indent at bottom left.  On closer inspection and after removing the chip I can see it may actually go to a round contact right below it.  See attached pic.  What are your thoughts on this?


Thanks for your help with this, it's been an interesting learning curve for myself.

Amendment.. I just read Screwtops link, thanks.  The link to the schematics is quite handy but from it it does look like pin5 for the Sony chip doesnt go anywhere... :/

It looks like I may have to do some continuity testing accross the board using the schematics website..



Regards

Steven

Check the voltages on the Q components. As I think you were reading them wrong.
Measure from board ground, then positive on each pin of Q components.

[swood123]

I had the negative lead on the shielding for the TV outlet and I put the positive on the Transistor (bottom left connector), which I understand is base.  I have been using a brand new modern power supply I bought, surely power supply should be okay.

I guess to recheck I assume I will need to resolder the Sony chip back to the board now.  I shall do this later when I get away from work.


Regards

Steven

[swood123]

I replaced the Sony chip and checked continuity to all contacts around the chip, they were all fine and then I decided to just check over the whole board and I noticed a small short on the back of the board....... it now works

Well what a learning curve that has been for me.  Very enjoyable.  Now my son can play some games on it

Thanks all for the guidance.


Merry xmas

Steven

[screwtop]

Well done! That's a great Christmas gift in my books.

[F0LLETT]

I replaced the Sony chip and checked continuity to all contacts around the chip, they were all fine and then I decided to just check over the whole board and I noticed a small short on the back of the board....... it now works

Well what a learning curve that has been for me.  Very enjoyable.  Now my son can play some games on it

Thanks all for the guidance.


Merry xmas

Steven

Glad you got to bottom of it.