QU32 dead?

[WiltsParticipant]

Just before the midnight service last night, our QU32 suddenly started producing what sounded like square waves on all the output channels. I tried the obvious things (cycling the power, disconnecting everything but the mains, hard reset) but it still powers up in that state. The touchscreen does respond though.

I’m guessing it is a repair centre job but in the off chance it might be something I’ve overlooked I thought I would ask here first if anyone has had this problem and what they did about about.

Sadly it is out of warranty so I will be will be looking for a UK repairer. Any recommendations? Do any of these have loan items? Failing that, any cost effective hire companies in the UK where I can hire a replacement – a quick look indicated costs of £300 per week!

Alternatively, I don’t suppose anyone has a service manual do they?

Thanks

Paul

[ddff_lvParticipant]

Depending on how qualified you are, you might want to open the desk and check all the supply voltages (I’d start with +15 and -15 VDC that are feeding opamp buffers).

ddff

[MarkPAmanParticipant]

If it will let you, re-installing the firmware has to be worth a try.

As to a replacement desk, where in the UK are you?

[WiltsParticipant]

Mark
Thanks – wiill try a reinstall.

I’m based near Southampton.

[Dick ReesParticipant]

Just to be 100% sure…

You disconnected everything BUT THE MAINS. Before proceeding, I’d do two things:

1. Check to make sure the signal generator has not accidentally been engaged.

2. Disconnect the mains as well and listen to the board on headphones to see if it is “full of noise”. If you get no noise on the headphones, start re-connecting things one at a time until the noise returns.

Good luck, and remember what Douglas Adams advised: DON’T PANIC.

[WiltsParticipant]

Sadly a reinstall didn’t work. I put a scope on an output and got 50Hz square waves at +10 to -4v, even with the desk shutdown prior to mains off. Sounds like a PSU problem to me……

[WiltsParticipant]

For completeness, it was PSU failure. A capacitor had gone short circuit on the -15v analogue rail. Not exactly a cheap repair……

[Author]

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