HC533 + Rev 5 A500 + 1.3 = No sound?

[chiark]

Well, this is an odd one.

Finally got around to fitting my HC533. Lovely bit of kit, does what I need to do, however... Whenever it's installed, I get no audio.

Remove it and fit 68k? Audio returns.

I've changed Paula. No difference. I've changed the PSU in case something's happening to the -12v line. No difference. I've jumpered for Oktagon controller, no difference.

Anyone got any suggestions before I start digging out the probes? I can't see anyone else having this issue from a search, so I'm stumped. Any suggestions gratefully received!

[Snoopy1234]

I had the first [black pcb] release HC533 which I sold but when I had it on my A500+ it had no problem. I did experience df0: issues but that might have been something else.
Maybe the board is touching some other component or not seated correctly, or even a faulty board?

[chiark]

Thanks! Yes, mine's a black board and is from 2019 or so I think. df0 working fine, in fact everything working fine, which is why I'm so stumped. I haven't checked serial port as I did wonder if something was bringing the -12v line down, but that's not brought out at the CPU.

I've put a plastic sheet underneath to make sure nothing's shorting.

COuld be a faulty board but I am really at a loss as to why only audio would be affected - if paula was being affected then the drive wouldn't work either.

[Jope]

I had a HC533 with a speedy e-clock. Maybe check Amiga Test Kit CIA timer tests to see what they think.

[chiark]

Good point, will try that - thanks Jope. I've checked voltages and it's all good. The only thing I can think is that the interrupt for sound isn't being generated. But interrupts for everything else is!