Boss PH-2 IR3109 Chips removed. Worth repair?

Started by broomhandle, May 24, 2024, 06:30:03 PM

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broomhandle

I made a video to show the difference. It feels almost like the chips are distorting. And maybe this has nothing to do with the chips. Original ('95) is on the left, replaced chips ('97) is on the right.


ElectricDruid

I agree that's it's definitely not quite right just yet!

It's shame that they didn't socket the chips originally because then we'd have an easy test to see if it was the chips - swap them over from one unit to the other. Oh well...

TBH, I think it's fairly unlikely. What's more likely is that there's something else wrong with it.

I think it's time to break out the audio probe and see what you can find.

broomhandle

Quote from: ElectricDruid on June 14, 2024, 12:39:00 PMI think it's time to break out the audio probe and see what you can find.

I would not know where to start. Could some sort of ground issue do this? Also, I tore off one of the pads. Maybe my patch is incorrect?

ElectricDruid

Quote from: broomhandle on June 14, 2024, 02:43:17 PMI would not know where to start.
That's ok, we can guide you.

QuoteCould some sort of ground issue do this?
It doesn't *sound* like a ground problem.

QuoteAlso, I tore off one of the pads. Maybe my patch is incorrect?
No, you're just worrying. Your patch was fine.

I'll post some test points for you to try, but it's friday night, so I've got some fun to have first!

broomhandle

Here is the bottom of the board. And my repair because I lifted the pad. It is possible that I connected some points that are not supposed to be connected.






ElectricDruid

Here's some points to test to see how far the audio gets before it goes bad.





It's not the easiest board to debug because it's so dense, but if you can narrow it down a bit, we can probably find what's wrong.

Good luck and let us know what you find!

broomhandle

This is great. So how would I test? Audio probe? We know the board has power. So I am not sure what I am testing. I would think 1st and 2nd stages..but how to test that..

bluebunny

Yes, audio probe.  Follow Tom's test points in order.
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