ZED 6 power supply issue

[simi]

ZED 6 is nice compact mixer, but its switching power supply contains few design flaws. These results in psu fail after not so long runtime. If somebody has this problem, I can share solution.

[bjornvla]

Hello,

I got a zed-6 which i use on my desk to control different inputs.
it has never been outside and all of sudden it doesn’t turn on anymore.
i think i have the power supply issue.
do you think you can help me?

Thanks

Bjorn

[Pete Alcock]

Hi Simi,

You say you have a solution to the SMPS problem. Might you be able to share it with me? I’ve seen a couple of small ZED mixers with failed SMPS now.

Many thanks,

Pete.

[jimbob]

Ive had 4 of these mixers die now, would love to know what the fix is please!

[pedromrquez]

Still no answers on this chat. I hope Simi could answer us someday. Isn’t the point of a forum to help each other with knowledge and experience?
Did you guys take it for repair, or change the PSU yourselves? wondering if someone did eventually solve the problem. I have a ZEDi8 but I believe they share the same PSU.
Thanks!

[ANH]

I am just in the process of repairing a Zedi-8 mixer with a bad power supply. Diode D7 is shorted. The same fault is mentioned here https://www.eevblog.com/forum/repair/smps-repair-allen-and-heath-6-channel-mixer/ Diode is an SB1100

[pedromrquez]

ANH, Thank you!
That’s the spirit! This is extremely helpful. I’ve done some soldering in the past so might give this a go.
Thanks a lot,
P.

[ANH]

No problem! You might need to use SR1100 as a replacement, I think it’s easier to find. You might like to check the 7912 -12v regulator is not shorted. Mine seems ok. I will change both SB1100 diodes for new in case they were a bad run, and I think SR1100 is slightly better rated. Let me know if you need any help at all 🙂

[ernestoR]

Hi, thanks to ANH for sharing the images; the same PCB seems to be used in ZED6. I had to remove it from my recently bought ZED6 mixer because U1 (is it a TNY 187?) was exploded. Now I wanted to apply external power supply. Unfortunately I did not note down all connections between the PSU PCB and the Master PCB. IIRC there were only three connections from P1 (+48V), P6 (+12V) and P12 (-12V) on the PSU to the Master PCB’s P7, P10, P14. Can anyone help me with the correct cabling? May be with the Master PCB schematic or so?
Thanks a lot in advance!
Bets regards
Ernesto

[ANH]

Can anyone help me with the correct cabling?

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[ANH]

Hopefully these images point you in the right direction.

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[ernestoR]

Hm, thanks for sharing this. At least in my case it looks a bit different. The orange wire (in zedb.jpg and zedc.jpg) seems to be Ground — but in my ZED6 there was no separate Ground wire, I’m quite sure. Is it possible that Ground connection is realized differently in ZED6? Master PCB had only three wires connected: red, blue and pink as in zedg.jpg, but not the orange one.
Is it possible to make a direct Ground connection from my new PSU to the so far unused P13 on Master PCB? I’m hesitating a bit to just try it because I do not want to blow up my nice ZED6 …

Thanks for any further help!

p.s.: attached the blown up IC

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[ANH]

The orange wire doesn’t connect to the power pcb. It’s just those 3 small wires.

[KeithJ A&H]

Please note that user ‘ANH’ is not an official representative from A&H.

Although we don’t like waste, and of course it’s completely up to the individual what they wish to do with any product of ours which has an issue outside of the warranty period – we really REALLY recommend that repairs are only carried out by experienced service technicians, especially those at or working with our distribution partners.

This ensures that your A&H product performs to spec, but far more importantly there are dangerously high DC voltages which will kill you if you don’t know what you’re doing.

Thanks,
Keith.

[ernestoR]

Hi Keith, thanks for this information, I understand. But just because of safety issues my plan is to apply power from an external unit instead of repairing the original one. I only want to make sure where and how to apply ground wire. I’m an engineer in electronics; I understand the risks and love my life!
It’s a pity that my original PSU unit just had the exploded IC (please refer to image above); the ZED6 is a quite good device IMHO.
Best regards!

[Author]

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