HELP!! No power to desk

[leonidspaul]

I was ready to mix the final track before sending it off to the pressing plant and this happens. Just as i go to power on my Allen and Heath GL2200, there is no life in her. If there are any people with electrical knowledge please please i need your help. Is this likely to be something i could fix myself or does it sound more serious?? Thanks... Paul

[Maschinengeist]

First, check the fuse. A visual inspection may reveal the problem, especially if the glass is spotted. Replace by the same value (printed on the metal cap). Otherwise, use a multimeter and set it to OHM. If your fuse offers resistance, it is blown.

If the fuse is ok, it may be the switch or the power supply. Then it might take a tech to inspect it. It could be a lot of things from defective transformer, diode, voltage regulator, etc.

I don't currently have the service manual nor the schematics. But I've just my suppliers and they can find me one.

[leonidspaul]

Thanks a lot Maschinengeist. I took the fuse out and it was blown. i feel very relieved. Appreciate the advice!!! Paul

[OriginalJambo]

Isn't it great when it's just something that simple?

[Maschinengeist]

Thanks a lot Maschinengeist. I took the fuse out and it was blown. i feel very relieved. Appreciate the advice!!! Paul

My pleasure Paul.

Funny story: some of my customers took their gear to a tech (hey, the damn thing no longer work!) and they had one big bill (hey, the techs have all their policy, like 1 hour min.more or less). Not to say that they are dishonest (hey, I am a tech!). Myself had a problem at my house and had to call a professional. Cost me $85 + taxes for less than 15 m work (and it turned out to be a little stupid thing... but I didn't know what the h**l was wrong).

[leonidspaul]

Well do i feel stupid?!! I was a bit hasty in my reply, yes the fuse was blown but i just replaced the old fuse with exact same new fuse and the same thing just happened. Thinking it might be the IEC lead i switched that replaced the fuse again and the same. The green led power light turns on, then there's an audible hum and then lights out. I'm thinking i will have to get a service no?? Frustrated...

[Maschinengeist]

You don't have to feel stupid. Sometimes, just changing the fuse once is enough.

But if your hear a hum + multiple fuse blow, the power supply is to be verified by a professional. Chances are that the transformer and possibly a power transformer are problematic (to name just those two).

Don't venture there if you have no electronic knowledge. There is high voltage there which could harm if not kill you.

Oh, I just received the service manual with schematics too (if in case your tech doesn't have it already).

[leonidspaul]

Yeah i'm going to send her off, i'd probably end up causing more damage if i went messing around with it. On the plus side though, i'll be getting a loan of a Midas Venice so it's not all bad news! I'll find out if he has the schematics and if he doesn't i'll grab them from you. Thanks very much. Paul

[cornutt]

My guess is that a filter cap in the power supply is shorted. If that's what it is, it's not a hard thing to fix; however, if you aren't familiar with working with line-voltage circuits, it's not a good thing to mess with. Assuming that the PS isn't hard to get to, it should be fairly straightforward for a tech to fix it.