Switch mode PA Amp PSU fault

[Yorkie]

David,

Might I respectfully say 'Pillock'.

Many moons ago the Company I was working for had supplied some gear to another Company who we didn't normally deal with. The gear included a NiCad battery which was float charged from the supply. After a couple of Months they complained that all the Batteries were dead. At the time we were having some problems with supplies of Cells, so we sent new Batteries. After another couple of Months they complained again. It turned out that they ran the gear for a few days then turned the power off and went away for a couple of weeks to do some more design. Put simply that was not, and never was, what it was designed to do.

I would suggest that you are/were in a similar situation.

Alan

None of the above has any relevance. The instructions clearly state: "While charging, the unit may be operated simultaneously". There are no cautionary notes about only using the unit when the battery is fully charged. All of the equipment - projectors, lathe, PA system, projectors, screens etc, is stored in a village hall. It's used once a month for two hours. We would have preferred a small PA system which is simply mains powered, but at the time of purchase (when we consulted a national audio visual equipment sales and hire company), no suitable alternative equipment was available. The SLA battery isn't fully discharged when we set the equipment up, but only lasts for about half an hour, so we plug in the PSU at the outset. Short of someone (ie me,) taking it home to store and re-charge it each month is readiness for use, we use it in accordance with the instructions - 'simultaneously using and charging'. (The PSU is rated at 4 AMPS).

(It is jiggered by the way, so I'll be sourcing a replacement).

Thanks guys for all the advice and guidance, but having checked the bridge and replaced the el cap, there is still no output, and as both sides of the PCB, with a high component density, is peppered with SMDs, I have neither the time, expertise nor inclination to furtle about with it any further. IMHO, five years for a PSU from China sounds about par for the course, albeit it looks well constructed, and I don't label everything that comes out of China as tat).